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Author Topic:   The Age of the Earth (version 3 no 1 part 3)
RAZD
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Posts: 18867
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Joined: 03-14-2004
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(1)
Message 1 of 9 (816566)
08-06-2017 11:51 AM


Age of the Earth
Part 3 - Radiometric and Cosmogenic Measuring Systems

Correlations, Calibrations and Consilience

As noted in both Part 1 (Biological Counting Systems) and Part 2 (Physical/Chemical Counting Systems), we see many age deniers saying that dating methods are not accurate and are prone to errors. We saw from both the Biological Counting Systems and the Physical/Chemical Counting Systems that several methods and independent data sets all correlated with each other and showed remarkable consilience in several rather astounding ways, especially given that they are based on different mechanisms -- unless they are indeed accurate and precise records of actual age.

Once again, to address this issue of correlations, and the consilience of different systems, we now extend the measurement systems into the radiometric and cosmological methods used to measure age. We will start with systems that correlate directly with the previous systems. As we move through different methods, we will discusses how those methods corroborate and agree with each other and how they corroborate and agree with both the Biological Counting Systems and Physical/Chemical Counting Systems.

In addition, we will discuss correlations and consilience not just with different age measuring mechanisms, but with past climate changes and certain known cyclic patterns, things that show up in multiple records just the way they should if the age measurements are accurate.

Again, I do not ask you to discard your skepticism, I just ask that you temper it with an open mind.

The challenge for the age deniers is not just to describe how a single method can be wrong, but how they can all be wrong at the same time and in the same way to produce virtually identical results (within the margins of error) - when random results or systematic errors in different methods should produce notably different results:

The challenge for old age deniers (especially young earth proponents) is to explain why the same basic results occur from different measurement systems if they are not measuring actual age?

Additional information has become available since the last version of this topic, and I felt it should be combined with the previous version in a new revised and updated thread because it is important to understand the kind of work scientists do to validate their methods. In addition, there are a couple of corrections that I need to make for scientific accuracy, some assertions of a dubious nature have been dropped, and (finally), I will continue using a slightly different format from previous threads (and I'll continue using the Definitions of Some Terms Used from Part 1 (Message 2)):

  • Accuracy
  • Precision
  • Concordance
  • Correlation
  • Calibration
  • Consilience
  • Confidence

This part covers:

Message 2, Tick Tock Solar Clock, the "11-year Schwabe solar cycle,"
Message 3, Devil's in the Details, a calcite vein in Nevada, the earth is at least 567.7 thousand years old.
Message 4, Thorium-230 and Protactinium-231, validating radiometric dating methods
Message 5, Uranium Halos, the constancy of physical decay constants for millions of years
[msg=6], The Ages of the Grand Canyon, dating mammillies shows it took over 14 million years to reach its current form, and the earth is at least 17 million years old
[msg=7], Talking Coral Heads, lunar orbital interactions, the earth is at least 600 million years old.
[msg=8], The Oklo Reactors, an extinct natural nuclear reactor, age of the earth is at least 1.74 billion years old.
[msg=9], A String of Pearls, a chain of meteor craters, further validating radiometric dating methods
*[msg=10], The Radiometric Age of the Earth, f 4.5 billion years old.
*[msg=11], Accuracy and Precision of Radiometric Methods
*[msg=12], Carbon-14 Decay Revisited, consilience with radiometric measurements
*[msg=13], Climate Correlations, how climate data provides further validation of age measurements.
*[msg=14], Summary, correlations, consilience and confidence: the earth is very, very, very old, get used to it.

* in progress

Again, people who want to review the earlier versions of this work can do so at:

  1. Age Correlations and an Old Earth Version 1 number 1 (297 posts)
  2. Age Correlations and an Old Earth: Part II. Version 1 number 2 (306 posts)
  3. Age Correlations and an Old Earth: Version 1 No 3 (formerly Part III) (357 posts)
  4. Age Correlations and An Old Earth, Version 2 No 1 (currently 578 posts)

As yet, even though several attempts have been made to question individual methods, the consilience of the different methods arriving at the same basic results has not yet been explained or even attempted.

Enjoy.

Note: all images used on this thread, and subsequent posts that this one refers to with links, may be copied to a mirror site - without any modification or any intent to take credit for them. In every case I reference the original site where they can be viewed in context and verified as needed. The only purposes to copying the images is (a) to include PDF images, (b) to reduce band-width traffic on the original websites when these images are accessed, and (c) to ensure that the images are available in these post should the original sources be changed or removed from the web.

Where possible, I have tried to follow standard procedures for citing online publications, where if I had accessedAge Correlations and An Old Earth, Version 2 No 1 on 29May2014, I would cite this as:

Smith, P., Age Correlations and An Old Earth, Ver 2 no 1, EvC Forum, [2014, May 29], 2010 May 12 update http://www.evcforum.net/cgi-bin/dm.cgi?action=msg&t=6288.

Where websites are used instead of scientific articles they will be identified similar to this:

Anon, Dictionary.com (website), confidence, [2015, March 01]: http://dictionary.reference.com/browse/confidence?s=t

Where the date in brackets is the date the website was accessed.

Edited by RAZD, : .

Edited by RAZD, : restructured


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Replies to this message:
 Message 2 by RAZD, posted 08-06-2017 5:28 PM RAZD has responded

  
RAZD
Member
Posts: 18867
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.6


Message 2 of 9 (816581)
08-06-2017 5:28 PM
Reply to: Message 1 by RAZD
08-06-2017 11:51 AM


Tick Tock Solar Clock

Tick Tock Solar Clock

As mentioned in Part 2, (Physical/Chemical Counting Systems), (Ice Cores, 14C and 10Be, the Berillium-10 (10Be) levels tracked the "11-year Schwabe solar cycle," a pattern that also shows up in the Carbon-14 (14C) tree ring and lake varve chronologies.

Solar cycle(1)

quote:
The solar cycle or solar magnetic activity cycle is the nearly periodic 11-year change in the Sun's activity (including changes in the levels of solar radiation and ejection of solar material) and appearance (changes in the number and size of sunspots, flares, and other manifestations).

They have been observed (by changes in the sun's appearance and by changes seen on Earth, such as auroras) for centuries.

The changes on the sun cause effects in space, in the atmosphere, and on Earth's surface. While it is the dominant variable in solar activity, aperiodic fluctuations also occur.

The solar cycle was discovered in 1843 by Samuel Heinrich Schwabe, who after 17 years of observations noticed a periodic variation in the average number of sunspots.[2] Rudolf Wolf compiled and studied these and other observations, reconstructing the cycle back to 1745, eventually pushing these reconstructions to the earliest observations of sunspots by Galileo and contemporaries in the early seventeenth century. ...The cycle's physical basis was elucidated by Hale and collaborators, who in 1908 showed that sunspots were strongly magnetized (the first detection of magnetic fields beyond the Earth). In 1919 they showed that the magnetic polarity of sunspot pairs:

  • Is constant throughout a cycle;
  • Is opposite across the equator throughout a cycle;
  • Reverses itself from one cycle to the next.

Hale's observations revealed that the complete magnetic cycle spans two solar cycles, or 22 years, before returning to its original state. However, because nearly all manifestations are insensitive to polarity, the "11-year solar cycle" remains the focus of research.

Sunspot numbers over the past 11,400 years have been reconstructed using Carbon-14-based dendroclimatology.

The Sun's apparent surface, the photosphere, radiates more actively when there are more sunspots. Satellite monitoring of solar luminosity revealed a direct relationship between the Schwabe cycle and luminosity with a peak-to-peak amplitude of about 0.1%.[21] Luminosity decreases by as much as 0.3% on a 10-day timescale when large groups of sunspots rotate across the Earth's view and increase by as much as 0.05% for up to 6 months due to faculae associated with large sunspot groups.[22]

The best information today comes from SOHO (a cooperative project of the European Space Agency and NASA), such as the MDI magnetogram, where the solar "surface" magnetic field can be seen.

The outward expansion of solar ejecta into interplanetary space provides overdensities of plasma that are efficient at scattering high-energy cosmic rays entering the solar system from elsewhere in the galaxy. The frequency of solar eruptive events is modulated by the cycle, changing the degree of cosmic ray scattering in the outer solar system accordingly. As a consequence, the cosmic ray flux in the inner solar system is anticorrelated with the overall level of solar activity. This anticorrelation is clearly detected in cosmic ray flux measurements at the Earth's surface. The effect amounts to several percent variation over the solar cycle, greater than the typically 0.1% variation in total solar irradiance.[40][41]

Some high-energy cosmic rays entering Earth's atmosphere collide hard enough with molecular atmospheric constituents to cause occasionally nuclear spallation reactions. Fission products include radionuclides such as 14C and 10Be that settle on the Earth's surface. Their concentration can be measured in ice cores, allowing a reconstruction of solar activity levels into the distant past.[42] Such reconstructions indicate that the overall level of solar activity since the middle of the twentieth century stands amongst the highest of the past 10,000 years, and that epochs of suppressed activity, of varying durations have occurred repeatedly over that time span.

Solar maxima and minima also exhibit fluctuations at time scales greater than solar cycles. Increasing and decreasing trends can continue for periods of a century or more.

The 87 year (70–100 year) Gleissberg cycle, named after Wolfgang Gleißberg, is thought to be an amplitude modulation of the Schwabe Cycle,[5][27][28]


While these aren't annual events, they are periodic, and the cyclic effect on the generation of 14C and 10Be are recorded in tree rings and lake varves and ice cores, as peaks and valleys in the data record.

This "ticking of the solar clock" then provides another check on the accuracy and precision of the tree ring, lake varve, and ice core chronologies, and the consilience of all these systems agreeing with each other and the 11-year cyclic (Schwabe) pattern show a very high degree of accuracy and precision.

But that's not all:

Milankovitch cycles(2)

quote:
Milankovitch cycles describe the collective effects of changes in the Earth's movements on its climate over thousands of years. The term is named after Serbian geophysicist and astronomer Milutin Milanković. In the 1920s, he theorized that variations in eccentricity, axial tilt, and precession of the Earth's orbit resulted in cyclical variation in the solar radiation reaching the Earth, and that this orbital forcing strongly influenced climatic patterns on Earth.

Now, materials on Earth that have been unchanged for millennia are being studied to indicate the history of Earth's climate. Though they are consistent with the Milankovitch hypothesis, there are still several observations that the hypothesis does not explain.


These cycles are also visible in the 14C and 10Be, in fact it is this data that has confirmed the Melankovitch cycles are valid hypothesis. That the patterns in 14C and 10Be variations match with age is another piece of consilience, separate from the 11-year cyclic (Schwabe) pattern, and further evidence of the accuracy and precision of the tree ring, lake varve, ice core chronologies, and the Schwabe cycle, and the consilience of all these systems agreeing with each other show a very high degree of accuracy and precision.

Remember: The challenge for old age deniers (especially young earth proponents) is to explain why the same basic results occur from different measurement systems if they are not measuring actual age?

The earth is very, very, very old. Get used to it.

Enjoy

References

  1. Anon, "Solar cycle," Wikipedia.com (website), [2017] https://en.wikipedia.org/wiki/Solar_cycle
  2. Anon, "Milankovitch cycles," Wikipedia.com (website), [2017] https://en.wikipedia.org/wiki/Milankovitch_cycles

we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
to share.


• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

This message is a reply to:
 Message 1 by RAZD, posted 08-06-2017 11:51 AM RAZD has responded

Replies to this message:
 Message 3 by RAZD, posted 08-07-2017 3:55 PM RAZD has responded

  
RAZD
Member
Posts: 18867
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.6


Message 3 of 9 (816597)
08-07-2017 3:55 PM
Reply to: Message 2 by RAZD
08-06-2017 5:28 PM


Devil's in the Details

Devil's in the Details

Now we have reached back over 800,000 years for the age of the earth by methods that count annual layers (see Part 1 and Part 2), with each step along the way validating the method and age that was arrived at with the previous step. We are way past any age that can possibly be called a "young" earth concept, but we have not yet reached beyond the age of hominid fossils (although we are beyond the fossil record for Homo sapiens), and we still have a ways to go to get to billions of years.

We may, however, have reached the limits of annual counting systems to measure the age of the earth, but there are other ways to measure age.

To discuss radioactive decay and the validity of the dating systems that are based on this concept we need a system not subject to the kind of variation in Carbon-14 (due to variations in initial levels in the atmosphere). We also need one that can be correlated over substantial time to validate the system.

Data for Devil's Hole Core DH-11(1)

quote:
Devils Hole is a tectonically formed cave developed in the discharge zone of a regional aquifer in south-central Nevada. (See Riggs, et al., 1994.) The walls of this subaqueous cavern are coated with dense vein calcite which provides an ideal material for precise uranium-series dating via thermal ionization mass spectrometry (TIMS). Devils Hole Core DH-11 is a 36-cm-long core of vein calcite from which we obtained an approximately 500,000-year-long continuous record of paleotemperature and other climatic proxies. Data from this core were recently used by Winograd and others (1997) to discuss the length and stability of the last four interglaciations. These data are given in table 1.

Carbon and oxygen stable isotopic ratios were measured on 285 samples cut at regular intervals inward from the free face of the core (as reported in Winograd et al. ,1992, and in Coplen et al., 1994). Table 1 lists only 284 samples because a sample taken at 114.28 mm was eliminated when post-1994 reanalysis of its delta 18O value indicated an error in the earlier determination. Carbon isotopic ratios are reported in per mill (footnote #1) relative to VPDB, defined by assigning a delta 13C of +1.95 per mill to the reference material NBS 19 calcite. Oxygen isotopic ratios are reported relative to VSMOW reference water on a scale normalized such that SLAP reference water is -55.5 per mill relative to VSMOW reference water. The oxygen isotopic fractionation factors employed in this determination are those listed in Coplen and others (1983). The delta 18O value of the isotopic reference material NBS 19 on this scale is +28.65 per mill. The ± 1 sd (standard deviation) error for the delta 18O and delta 13C analyses is ±0.07 and 0.05 per mill, respectively.

Ages were estimated by linear interpolation between age control points taken at key intervals in the core and analyzed by TIMS 230Th-234U-238U dating. The age estimates in Table 1 are based on the original 21 control points (see Table 2 in Ludwig, et al., 1992, and Figure 2 in Winograd, et al., 1992) as well as for the recently obtained TIMS age of 143.8±0.9 ka (2 sd analytical error) at 51.5 mm (Winograd, et al., 1997). The later sample was taken specifically for additional control in a critical portion of the core. Errors in the ages vary but are bounded by the errors in the appropriate control points. (See Table 2 in Ludwig, et al., 1992.)


Once again we have correlations between age, climate and temperatures. They measured the age with a radiometric decay system at 21 control points, and interpelated between them for samples where δ18O and δ13C were measured as indicators of climate. There is a table with the 284 samples by age with d18O and d13C values. For a correlation of that data to the age and climate information we have already see in Part 2), Message 9 (Antarctic Ice Cores, we turn to:

Devils Hole, Nevada—A Primer(2)

quote:
Devils Hole is a subaqueous cavern in south-central Nevada within a geographically detached unit of Death Valley National Park (fig. 1). The cavern is tectonic in origin and has developed in Cambrian carbonate rocks bordering the Ash Meadows oasis (Carr, 1988). The open fault zone comprising the cave extends to a depth of at least 130 meters below the water table, which is about 15 meters below land surface (Riggs and others, 1994). The primary source of groundwater flowing through Devils Hole, and discharging from the major springs within the oasis, is precipitation on the Spring Mountains to the east of the cavern ...

The importance of Devils Hole to paleoclimatologists is twofold. Below the water table, the near-vertical walls of Devils Hole are coated with up to 40 centimeters of vein calcite that precipitated from groundwater moving through the cavern (fig. 2). The calcite can be accurately and precisely dated with radiometric methods, such that the depth-varying sequences of oxygen and carbon stable isotopes in the calcite provide a record of climatic variations spanning more than 500,000 years (Winograd and others, 1988, 1992, 2006). Additionally, subhorizontal cave deposits, called folia, record variations of the water table during the past 120,000 years (Szabo and others, 1994).

Since 1992, vein calcite samples have been uranium-series dated using thermal ionization mass spectrometric (TIMS) methodology (Ludwig and others, 1992). In 1997, the Devils Hole thorium-230 ages were independently confirmed by non-U.S. Geological Survey (USGS) investigators using protactinium-231 (Edwards and others, 1997).

The Devils Hole oxygen-18 (δ18O) time series (fig. 3) is primarily a proxy indicator of paleotemperatures. Unlike oxygen isotopes in deep-sea cores, it is not a record of past global ice accumulation in terrestrial systems. Rather, the time series appears to correspond, both in timing and relative magnitude, to variations in paleo-sea-surface temperature (SST) recorded in Pacific Ocean sediments off the west coast of North America, from Oregon to California, and as far south as the equatorial eastern Pacific (fig. 4) (Winograd and others, 1996, 1997, 2006; Lea and others, 2000; Herbert and others, 2001; Winograd, 2002). The Devils Hole δ18O record is also highly correlated with major variations in paleotemperatures recorded in the Vostok ice core from the East Antarctic Plateau (Landwehr and Winograd, 2001; Landwehr, 2002). ...



Note - "highly correlated" with climatological data from the Vostok ice core data, which "matches almost perfectly" the climatological data from the Greenland ice core data. Corroborated by two independent radiometric methods. The oldest date in the data table is 567,700 years ago (2005).

So what exactly do we have here? Ground water (acquifer discharge) flowing slowly through a cave formed tectonically in carbonate rock, depositing calcite and various other minerals and impurities on the wall, elements that are soluble in water, including trace levels of radioactive isotopes of uranium. Material that gets deposited as the calcite forms, layer after layer of similar deposits, each one trapping the impurities and other material in their respective layers. The calcite forms a matrix that holds the impurities, minerals and trace elements in a position related to the time the calcite was deposited.

Calcite(3)

quote:
Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). The Mohs scale of mineral hardness, based on scratch hardness comparison, defines value 3 as "calcite".

Calcite, like most carbonates, will dissolve with most forms of acid. Calcite can be either dissolved by groundwater or precipitated by groundwater, depending on several factors including the water temperature, pH, and dissolved ion concentrations. Although calcite is fairly insoluble in cold water, acidity can cause dissolution of calcite and release of carbon dioxide gas. Ambient carbon dioxide, due to its acidity, has a slight solubilizing effect on calcite. Calcite exhibits an unusual characteristic called retrograde solubility in which it becomes less soluble in water as the temperature increases. When conditions are right for precipitation, calcite forms mineral coatings that cement the existing rock grains together or it can fill fractures. ....


Because of the conditions of the formation of this cave in carbonate rock we know that this is a deposition/persipitation condition as the rock would have disolved if it were otherwise. There are also two newer cores taken in other caves in the same acquifer:

The Chronology for the δ18O Record from Devils Hole, Nevada, Extended Into the Mid-Holocene(4)

quote:
As discussed in Winograd and others (2006), after the DH–11 analysis had been published (Winograd and others, 1992), two additional calcite specimens were obtained from Devils Hole Cave no. 2 (DHC2), a similar cave approximately 200 m north of Devils Hole, but in portions of DHC2 that are up the hydraulic gradient (that is, upstream in the aquifer) from the near-surface DH–11 core site. Specimen DHC2–3, which was precipitated from 80,000 to 19,000 years before present, provided 41,000 years of new record plus a 20,000-year overlap with core DH–11 (Winograd and others, 1996). Specimen DHC2–8, which precipitated between 30,000 and 4,500 years before present, provided 14,500 years of new record plus an 11,000-year overlap with specimen DHC2–3 (Winograd and others, 2006). The overlapping DH–11, DHC2–3, and DHC2–8 time series of the ratios of stable oxygen isotopes (δ18O) were spliced together at 78,500 years before present (for the overlap between DH–11 and DHC2–3) and 24,500 years before present (for the overlap between DHC2–3 and DHC2–8), at points chosen to minimize any small chronological offsets in the overlapping time series.

Ages for the intervals sampled for oxygen isotopemeasurements in all three specimens were estimated by linear interpolation between age control points obtained with 230Th-234U-238U TIMS dating. Errors in the interpolated age estimates are bounded by the errors in the relevant control points for each interval (Ludwig and others, 1992; Winograd and others, 1997, 2006).

The δ18O time series for the extended Devils Hole chronology up to 160,000 years before present was illustrated in figure 2 of Winograd and others (2006). Note that because the specimens DHC2–3 and DHC2–8 were micromilled to obtain samples every 0.25 millimeter, the time intervals are finer in the more recent portion of the chronology (younger than 78,500 years before present) than in the older portions of Devils Hole core DH–11. Table 1 presents the values for the full record of the Devils Hole δ18O chronology, that is, from 567,700 to 4,500 years before present.


The consilience of the three cores for the same δ18O levels at the same measured ages shows this process is both accurate and precise, and the match of the overall chronology age vs climate marker δ18O to the same values and ages in the ice cores (see Part 2), Message 9 (Antarctic Ice Cores), again shows a consilience of results from different measuring systems that would not be expeceted unless they are all measuring the same thing: age. This consilience then confirms the dates of the ice cores to 567,700 years before present (1950), or to 567,767 years ago (2017), or back to 565,751 BCE. Well before all YECie "calculations" for the age of the earth combined.

The earth is at least 567.7 thousand years old by this precise and accurate data.

With this data we can now look further at the accuracy, precision and validity of thorium-230 and protactinium-231 dating in the next post, Message 4.

Remember: The challenge for old age deniers (especially young earth proponents) is to explain why there is so much consilience from different measurement systems, from different sets of data and from different sources of information ... if the earth is not old?

The earth is very, very, very old. Get used to it.

Enjoy

References

  1. Landwehr, J.M., Coplen, T.B., Ludwig, K. R., Winograd, I.J., and Riggs, A.C., "Data for Devil's Hole Core DH-11," Department of the Interior, US Geological Survey National Research Program. updated 1 Sep 2005. [2017] http://pubs.usgs.gov/of/1997/ofr97-792/
  2. Anon, "A Devil's Hole Primer" Department of the Interior, US Geological Survey National Research Program updated: 29 Dec 2004. [2017] http://water.usgs.gov/nrp/devilshole.html
  3. Anon "Calcite" Wikipedia.com (website), last edited 30 July 2017 [2017] http://en.wikipedia.org/wiki/Calcite
  4. Landwehr, J.M., Sharp, W.D., Coplen, T.B., Ludwig, K.R., and Winograd, I.J., "The Chronology for the δ18O Record from Devils Hole, Nevada, Extended Into the Mid-Holocene," Department of the Interior, U.S. Geological Survey Open-File Report 2011–1082, 5 p. 2011 (Available online only.) [2017] https://pubs.usgs.gov/of/2011/1082/pdf/ofr2011-1082.pdf

Edited by RAZD, : .

Edited by RAZD, : .


we are limited in our ability to understand
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... to learn ... to think ... to live ... to laugh ...
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• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

This message is a reply to:
 Message 2 by RAZD, posted 08-06-2017 5:28 PM RAZD has responded

Replies to this message:
 Message 4 by RAZD, posted 08-07-2017 4:05 PM RAZD has responded

  
RAZD
Member
Posts: 18867
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.6


Message 4 of 9 (816598)
08-07-2017 4:05 PM
Reply to: Message 3 by RAZD
08-07-2017 3:55 PM


Thorium-230 and Protactinium-231

Thorium-230 and Protactinium-231

Because the δ18O Record from Devil's Hole, Nevada is so highly correlated with the δ18O variations recorded in the Vostok ice core from the East Antarctic Plateau, we can use this data not as an extension of the measurements of age of the earth, but as validation for the radiometric age calculations used. Correlations work both ways, the one validating the other.

In other words we "wiggle-match" (see Message 17 of Part 1 -Biological Counting Systems) the δ18O Records and then compare the age data from the ice cores to the remaining isotope levels in the Devil's Hole calcite vein to then compare that data to the predicted decay curves.

Radioactive elements like Uranium-234, Uranium-235 and Uranium-238, which are all soluble in water, decay into daughter elements, and some of these are not soluble, such as thorium-230 (230Th) and protactinium-231 (231Pa). Thus the presence of these insoluble daughter elements is evidence of decay of the soluble parent elements. These daughter elements become trapped in the layers of calcite as it is deposited as the parent elements decay, and then they start to decay: their depth in the calcite, and their level of decay relates directly to the age of the calcite layers where they are embedded.

We are interested in two such radioactive isotopes of these matrix constrained elements -- thorium-230 and protactinium-231 -- and what they can tell us about radiometric age measurements.

Radiometric Dating A Christian Perspective: Radiometric Dating of Geologically Young Samples (<100,000 Years) (page 15)(1)

quote:
There are other ways to date some geologically young samples. Besides the cosmogenic radionuclides discussed above, there is one other class of short-lived radionuclides on Earth. These are ones produced by decay of the long-lived radionuclides given in the upper part of Table 1. As mentioned in the Uranium-Lead section, uranium does not decay immediately to a stable isotope, but decays through a number of shorter-lived radioisotopes until it ends up as lead. While the uranium-lead system can measure intervals in the millions of years generally without problems from the intermediate isotopes, those intermediate isotopes with the longest half-lives span long enough time intervals for dating events less than several hundred thousand years ago. (Note that these intervals are well under a tenth of a percent of the half-lives of the long-lived parent uranium and thorium isotopes discussed earlier.) Two of the most frequently-used of these "uranium-series" systems are uranium-234 and thorium-230. These are listed as the last two entries in Table 1, and are illustrated in Figure 10.

Like carbon-14, the shorter-lived uranium-series isotopes are constantly being replenished, in this case, by decaying uranium-238 supplied to the Earth during its original creation. Following the example of carbon-14, you may guess that one way to use these isotopes for dating is to remove them from their source of replenishment. This starts the dating clock. In carbon-14 this happens when a living thing (like a tree) dies and no longer takes in carbon-14 laden CO2. For the shorter-lived uranium-series radionuclides, there needs to be a physical removal from uranium. The chemistry of uranium and thorium are such that they are in fact easily removed from each other. Uranium tends to stay dissolved in water, but thorium is insoluble in water. So a number of applications of the thorium-230 method are based on this chemical partition between uranium and thorium.

On the other hand, calcium carbonates produced biologically (such as in corals, shells, teeth, and bones) take in small amounts of uranium, but essentially no thorium (because of its much lower concentrations in the water). This allows the dating of these materials by their lack of thorium. A brand-new coral reef will have essentially no thorium-230. As it ages, some of its uranium decays to thorium-230. While the thorium-230 itself is radioactive, this can be corrected for. The equations are more complex than for the simple systems described earlier, but the uranium-234 / thorium-230 method has been used to date corals now for several decades. Comparison of uranium-234 ages with ages obtained by counting annual growth bands of corals proves that the technique is highly accurate when properly used (Edwards et al., Earth Planet. Sci. Lett. 90, 371, 1988). The method has also been used to date stalactites and stalagmites from caves, already mentioned in connection with long-term calibration of the radiocarbon method. In fact, tens of thousands of uranium-series dates have been performed on cave formations around the world.

As with all dating, the agreement of two or more methods is highly recommended for confirmation of a measurement.


So soluble 238U decays to soluble 234U which decays to insoluble 230Th.

At the Devil's Hole we are essentially dealing with one very large stalactite. As the calcite precipitates out of the water and is deposited on the calcite vein, so too is the 230Th deposited on the calcite, and it could only come from the decay of the parent 234U, with older layers containing less and less Th-230 as it decays after being deposited.

Note this mentions dating marine corals by the same method, and we saw this noted with the Lake Suigetsu data. We will talk more about coral heads later in [msg=7], Talking Coral Heads.

Thorium: Isotopes(2)

quote:
Thirty radioisotopes have been characterised, which range in mass number from 209[19] to 238.[17] The most stable of them (after 232Th) are 230Th with a half-life of 75,380 years, ...

In deep seawaters the isotope 230Th becomes significant enough that the International Union of Pure and Applied Chemistry reclassified thorium as a binuclidic element in 2013, as it can then make up to 0.04% of natural thorium.[1] The reason for this is that while its parent 238U is soluble in water, 230Th is insoluble and thus precipitates to form part of the sediment, and may be observed doing so. Uranium ores with low thorium concentrations can be purified to produce gram-sized thorium samples of which over a quarter is the 230Th isotope, since 230Th is one of the daughters of 238U.[17]


So the Thorium-230 precipitates out as the calcite precipitates out, forming a layer with the Thorium-230 trapped inside as the layer forms. It decays with a half-life of 75,380 years, and as seen in Message 3, Devil's in the Details, this can be used to date the layers and then, through the "highly correlated" δ18O record in the calcite vein with the δ18O record in the Vostock ice cores for those dates, validate the ice core dates ... so we can turn this around and say that the strong δ18O correlation validates the Thorium-230 radiometric ages, being "highly correlated" with the Vostock ice core layer ages.

Note that in reference (1) quoted above, Dr Weins said:

quote:
As with all dating, the agreement of two or more methods is highly recommended for confirmation of a measurement.

And we have that with the other radioactive isotope found in the calcite vein, protactinium-231.

Protactinium: Isotopes(3)

quote:
Twenty-nine radioisotopes of protactinium have been discovered, the most stable being 231Pa with a half-life of 32,760 years, ...

Protactinium is one of the rarest and most expensive naturally occurring elements. It is found in the form of two isotopes – 231Pa and 234Pa, ... Nearly all natural protactinium is protactinium-231. It is an alpha emitter and is formed by the decay of uranium-235, ... Protactinium is homogeneously dispersed in most natural materials and in water, but at much lower concentrations on the order of one part per trillion, that corresponds to the radioactivity of 0.1 picocuries (pCi)/g. There is about 500 times more protactinium in sandy soil particles than in water, even the water present in the same sample of soil. ...


So the Protactinium-231 is also deposited as the calcite precipitates out, forming a layer with the Protactinium-231 trapped inside as the layer forms. It decays with a half-life of 32,760 years. As seen above, this too can be used to date the layers and then, through the "highly correlated" δ18O record in the calcite vein with the δ18O record in the Vostock ice cores for those dates, validate the ice core dates ... and we can turn this around as well and say that the δ18O correlation validates the Protactinium-231 radiometric ages, being "highly correlated" with the Vostock ice core layer ages ... and with the Thorium-230 radiometric ages, forming a 3-way consilient correlation, with the added confidence in the accuracy and precision such consiliences provide.

As noted above Thorium-230 is formed from 234U decay which is formed from 238U decay, and Protactinium-231 is formed from 235U decay, and these are two different decay sequences with different daughter element isotopes.

Decay chain: Actinide alpha decay chains(4)

quote:
The three naturally-occurring actinide alpha decay chains given below—thorium, uranium/radium (from U-238), and actinium (from U-235)—each ends with its own specific lead isotope (Pb-208, Pb-206, and Pb-207 respectively). ...

The 4n+2 chain of U-238 is called the "uranium series" or "radium series". Beginning with naturally occurring uranium-238, this series includes the following elements: astatine, bismuth, lead, polonium, protactinium, radium, radon, thallium, and thorium. All are present, at least transiently, in any natural uranium-containing sample, whether metal, compound, or mineral. The series terminates with lead-206.

The 4n+3 chain of uranium-235 is commonly called the "actinium series" or "plutonium cascade". Beginning with the naturally-occurring isotope U-235, this decay series includes the following elements: actinium, astatine, bismuth, francium, lead, polonium, protactinium, radium, radon, thallium, and thorium. All are present, at least transiently, in any sample containing uranium-235, whether metal, compound, ore, or mineral. This series terminates with the stable isotope lead-207.


Radiation decay curves are exponential, with different results for different decay constants - the half-lives of the radioactive isotopes.

Exponential decay(5)

quote:
A quantity is subject to exponential decay if it decreases at a rate proportional to its current value. Symbolically, this process can be expressed by the following differential equation, where N is the quantity and λ (lambda) is a positive rate called the exponential decay constant:

N(t) = N0et

Here N(t) is the quantity at time t, and N0 = N(0) is the (initial) quantity, at time t=0.

A more intuitive characteristic of exponential decay for many people is the time required for the decaying quantity to fall to one half of its initial value. This time is called the half-life, and often denoted by the symbol t1/2. The half-life can be written in terms of the decay constant, or the mean lifetime, as:

t1/2 = ln2/λ = Tln2

When this expression is inserted for T in the exponential equation above, and ln2 is absorbed into the base, this equation becomes:

N(t) = N02-t/t1/2

Thus, the amount of material left is 2−1 = 1/2 raised to the (whole or fractional) number of half-lives that have passed. Thus, after 3 half-lives there will be (1/2)3 = 1/8 of the original material left.


Using the half-lives of thorium-230 (75,380 years) and protactinium-231 (32,760 years), we can now draw the exponential curves for these isotopes (with % on the y-axis and time in k-yrs on the x axis, thorium in blue and protactinium in red):

This means we have a series of data with three different pieces of information: calcite layer age, Thorium-230 content and Protactinium-231 content. We also note that Thorium-230 has a half-life of 75,380 years, while Protactinium-231 has a half-life of 32,760 years - less than half the half-life of Thorium-230. This means that layer by layer the ratio of Thorium-230 to Protactinium-231 is different:

AgeδTh=Tht/ThoδPa=Tht/PaoδTh/δPa
75,380 0.5000 0.2029 2.46
150,760 0.2500 0.0412 6.07
226,140 0.1250 0.0084 14.96
301,520 0.0625 0.0017 36.86
376,900 0.0313 0.0003 90.82
452,280 0.0156 0.0001 223.77
527,660 0.0078 0.00001 551.35

So for these dates to be invalid there would have to be a mechanism that can layer by layer preferentially change the ratio of these two {elements\isotopes} within the solid calcite vein. No such mechanism is known to exist within the realms of reality.

The precise and accurate measurements for Thorium-230 levels in the calcite vein correlating with the accurate and precise Vostok ice core layer ages show that the decay predicted by the half-life of 75,380 years is also accurate and precise.

The precise and accurate measurements for Protactinium-231 levels in the calcite vein correlating with the accurate and precise Vostok ice core layer ages show that the decay predicted by the half-life of 32,760 years is also accurate and precise.

The precise and accurate measurements for Protactinium-231 levels in the calcite vein correlating with the accurate and precise measurements for Thorium-230 levels in the calcite vein also show that the decay predicted by the half-lives is accurate and precise.

This 3-way consilient correlation, gives us very high confidence in the accuracy and precision of these radiometric methods for measuring age.

Based on this information alone we can conclude:

  • The theoretical basis for radiometric dating is precise, accurate and valid.
  • The two different radiometric methods are equally valid - at least as far back as 567,700 yr BP.
  • That there was no magical change in the behavior of radioactive materials in the last 567,700 years.

Simply put, radiometric age measurement is an accurate, precise and valid method for determining the age of objects.

Remember: The challenge for old age deniers (especially young earth proponents) is to explain why there is so much consilience from different measurement systems, from different sets of data and from different sources of information ... if the earth is not old?

The earth is very, very, very old. Get used to it.

Enjoy

References

  1. Weins, R.C., "Radiometric Dating A Christian Perspective: Radiometric Dating of Geologically Young Samples (<100,000 Years)," (page 15), The American Scientific Affiliation: A Fellowship of Christians in Scientists. First edition 1994; revised version 2002. [2017] http://www.asa3.org/ASA/resources/Wiens.html#page%2015
  2. Anon "Thorium: Isotopes," Wikipedia.com (website), last edited 18 August 2017 [2017] https://en.wikipedia.org/wiki/Thorium#Isotopes
  3. Anon "Protactinium: Isotopes," Wikipedia.com (website), last edited 25 June 2017 [2017]
    https://en.wikipedia.org/wiki/Protactinium#Isotopes
  4. Anon "Decay chain: Actinide alpha decay chains," Wikipedia.com (website), last edited 22 July 2017 [2017] https://en.wikipedia.org/...hain#Actinide_alpha_decay_chains
  5. Anon "Exponential decay," Wikipedia.com (website), last edited 31 July 2017 [2017] https://en.wikipedia.org/wiki/Exponential_decay

Edited by RAZD, : .


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 Message 5 by RAZD, posted 08-12-2017 6:39 AM RAZD has responded

  
RAZD
Member
Posts: 18867
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.6


Message 5 of 9 (816857)
08-12-2017 6:39 AM
Reply to: Message 4 by RAZD
08-07-2017 4:05 PM


Uranium Halos

Uranium Halos

We saw in Message 4, Thorium-230 and Protactinium-231, that radiometric dating methods are accurate, precise and valid methods for determining the age of objects. Now we are going to cover the constancy of the decay constants to further validate the radiometric dating methods, and we will do this with the evidence provided by Uranium Halos.

Many YECies are familiar with the claim that Polonium Halos are evidence of a young earth, a common PRATT that has been refuted many times (see PRATT CF201: Polonium Halos).

In 2004 I did some research into this issue (see Are Uranium Halos the best evidence of (a) an old earth AND (b) constant physics?) and I showed that the source of the "Polonium Halos" is Radon-222, (222Rn), a product of Uranium decay, which then decays into the three polonium isotopes (218Po, (214Po and (210Po). This was demonstrated by showing a radon-222 halo on some of Gentry's photographs like this:

Radon is a gas that easily penetrates thin cracks in granite and other rocks, like the gaps between veins of micas and other similar crystal lattice rocks where the halos have been found. When it decays the result is the three polonium isotopes in the halos. The existence of a radon ring then shows that the radon is the source of these halos.

But the real problem for YECies is the existence of Uranium halos, as they take millions of years to form.

Radiometric Dating, A Christian Perspective: Common Misconceptions ... 13. "Radiation halos" in rocks prove that the Earth was young. (page 25)(1)

quote:
This refers to tiny halos of crystal damage surrounding spots where radioactive elements are concentrated in certain rocks. Halos thought to be from polonium, a short-lived element produced from the decay of uranium, have been found in some rocks. ...

At any rate, halos from uranium inclusions are far more common. Because of uranium's long half-lives, these halos take at least several hundred million years to form. Because of this, most people agree that halos provide compelling evidence for a very old Earth.


The stock YECie response is that the decay rates changed, and thus all you are seeing is the result of fast decay rather than long time.

Aside from this being another PRATT (see CF210: Constancy of Radioactive Decay), the Uranium halos are very strong evidence that this did not occur, at least during the several hundred million years while the halos were forming, because physics.

The basic radiohalo principle is simple: radioactivity produces alpha decay, and the alpha particle have a certain energy (usually measured in million electron volts, MeV) based on the familiar e=mc² formula and the conservation of energy/mass:

M1 = M2 + mα + e/c²

Thus when you have one isotope (mass M1( decaying into other isotope (mass M2) by alpha decay (mass m&alpha), the energy of the alpha particle is unique to that decay stage because of the unique before and after mass of the decaying isotope and the constant mass of the alpha particle.

This unique energy then determines how far (on average) an alpha particle will travel before it gets stopped and absorbed into the surrounding material (and causes the ring pattern to be visible) and the result is a halo or a number of halos around decaying inclusions that look like rings, but are actually spherical, and something like this:

The halos require more than one particle to form as each particle only makes a point on the ring. Thus uranium, with it's long half-life, takes "several hundred million years to form."

Now the fun part: this is based on our knowledge of physics and the physical constants that tell us how things behave in the universe, so what happens if you have fast decay instead of old time?

Geiger–Nuttall law(2)

quote:
In nuclear physics, the Geiger–Nuttall law or Geiger–Nuttall rule relates the decay constant of a radioactive isotope with the energy of the alpha particles emitted. Roughly speaking, it states that short-lived isotopes emit more energetic alpha particles than long-lived ones.

The relationship also shows that half-lives are exponentially dependent on decay energy, so that very large changes in half-life make comparatively small differences in decay energy, and thus alpha particle energy. In practice, this means that alpha particles from all alpha-emitting isotopes across many orders of magnitude of difference in half-life, all nevertheless have about the same decay energy.

Formulated in 1911 by Hans Geiger and John Mitchell Nuttall,[1] in its modern form the Geiger–Nuttall law is

where λ is the decay constant (λ = ln2/half-life), Z the atomic number, E the total kinetic energy (of the alpha particle and the daughter nucleus), and a1 and a2 are constants. ...


Simply put, if you change the decay rate you change the energy of the α decay particle, and that changes the radius where the particle ends up. You would not have rings where they are, which are consistent with the decay energies observed today.

Alpha Barrier Penetration(3)

quote:
The energy of emitted alpha particles was a mystery to early investigators because it was evident that they did not have enough energy, according to classical physics, to escape the nucleus. Once an approximate size of the nucleus was obtained by Rutherford scattering, one could calculate the height of the Coulomb barrier at the radius of the nucleus. It was evident that this energy was several times higher than the observed alpha particle energies. There was also an incredible range of half lives for the alpha particle which could not be explained by anything in classical physics.

The resolution of this dilemma came with the realization that there was a finite probability that the alpha particle could penetrate the wall by quantum mechanical tunneling. Using tunneling, Gamow was able to calculate a dependence for the half-life as a function of alpha particle energy which was in agreement with experimental observations.


Why an alpha particle instead of simply a proton emission (like β decay with electrons)?

Alpha Binding Energy(4)

quote:
The nuclear binding energy of the alpha particle is extremely high, 28.3 MeV. It is an exceptionally stable collection of nucleons, and those heavier nuclei which can be viewed as collections of alpha particles (carbon-12, oxygen-16, etc.) are also exceptionally stable. This contrasts with a binding energy of only 8 MeV for helium-3, which forms an intermediate step in the proton-proton fusion cycle.

So I envisage it as a pyramid with each particle in each corner, in contact with each of the other particles, forming a very compact arrangement bound by the strong force. This is why we have alpha;++ particles instead of proton emission (like β- decay, with electrons).

Alpha Tunneling Model(5)

quote:
The illustration represents an attempt to model the alpha decay characteristics of polonium-212, which emits an 8.78 MeV alpha particle with a half-life of 0.3 microseconds. The Coulomb barrier faced by an alpha particle with this energy is about 26 MeV, so by classical physics it cannot escape at all. Quantum mechanical tunneling gives a small probability that the alpha can penetrate the barrier. To evaluate this probability, the alpha particle inside the nucleus is represented by a free-particle wavefunction subject to the nuclear potential. Inside the barrier, the solution to the Schrodinger equation becomes a decaying exponential. Calculating the ratio of the wavefunction outside the barrier and inside and squaring that ratio gives the probability of alpha emission.


The Coulomb barrier varies with each isotope nucleus, the larger the barrier the more the probability function decays and the less energy the particle has when it escapes and the lower probability to escape, and thus the longer the half-life.

And as β- particles don't have to escape the nucleus through the Coulomb barrier, their energy is not related to the half-life of the isotope.

Note, this similar argument is from the Christian Forums website in their Creation & Evolution section:

Uranium Halos--decay constants...constant (6)

quote:
As Uranium 238 decays through alpha-decay, the emitted alpha particles create damage to the surrounding rock, forming a sphere around the inclusion whose radius is dependent on the alpha particle decay energy.

They are called halos because we study them by looking at cross-sections of the sphere.

Now, it takes many decay events to form this visible sphere, since each atom that decays only produces one dot on the sphere. Something like 10^9 atoms of uranium need to decay in order to produce this sphere.

Since the half life of Uranium is about 4.5 billion years, in order for enough atoms to decay to form a halo, it would take hundreds of millions of years.

This is evidence of an old earth.

But there is more, it's also evidence that the decay constant of Uranium 238 has been constant for that time. Why?

Because the decay rate is inversely related to the decay energy. So, if the decay rate was faster in the past, the halo radius would be a different size. So, since the Uranium halos have a radius consistent with the decay energy that we observe today, we know that decay rates have not changed for hundreds of millions of years.


Hundreds of millions of years to form the 238U rings, with the decay rate constant enough that the result is a single ring (at 14.15 microns in photo below).

The existence of (common) uranium halos is evidence that shows the physical constants have not changed while they were formed, and their formation, in turn, is evidence that the earth is old, at least several hundred million years old.

Changes to physical constants need a cause.

Changes to physical constants have an effect.

The conceptual system that best ties all these together in a way that fits the observed evidence, with known cause and effect, is the current scientific system, with constant constants, and an earth with an old age, old enough for the Uranium Halos to form.

Based on this information alone we can conclude:

  • The theoretical basis for radiometric dating is precise, accurate and valid.
  • The two different radiometric methods are equally valid - at least as far back as several hundred million years ago.
  • That there was no magical change in the behavior of radioactive materials in the last several hundred million years.

Simply put, radiometric age measurement is an accurate, precise and valid method for determining the age of objects.

Remember: The challenge for old age deniers (especially young earth proponents) is to explain why there is so much consilience from different measurement systems, from different sets of data and from different sources of information ... if the earth is not old?

The earth is very, very, very old. Get used to it.

Enjoy.

References

  1. Weins, R.C., "Radiometric Dating, A Christian Perspective: Common Misconceptions ... 13. 'Radiation halos' in rocks prove that the Earth was young." (page 25), The American Scientific Affiliation: A Fellowship of Christians in Scientists. First edition 1994; revised version 2002. [2017] http://www.asa3.org/ASA/resources/Wiens.html#page%2025
  2. Anon, "Geiger–Nuttall law," Wikipedia.com (website), last edited 12 August 2017 [2017] https://en.wikipedia.org/wiki/Geiger%E2%80%93Nuttall_law
  3. Nave, P., "Alpha Barrier Penetration," Hyperphysics (website) hosted by Georgia State U. Dept of Astronomy and Physics, [2017] http://hyperphysics.phy-astr.gsu.edu/...clear/radact.html#c3
  4. Nave, P., "Alpha Binding Energy," Hyperphysics (website) hosted by Georgia State U. Dept of Astronomy and Physics, [2017] http://hyperphysics.phy-astr.gsu.edu/...clear/radact.html#c4
  5. Nave, P., "Alpha Tunneling Model," Hyperphysics (website) hosted by Georgia State U. Dept of Astronomy and Physics, [2017] http://hyperphysics.phy-astr.gsu.edu/...clear/alptun.html#c2
  6. 46AND2, "Uranium Halos--decay constants...constant," Christian Forums, Creation & Evolution (website), [2017] https://www.christianforums.com/...onstants-constant.7803853

Edited by RAZD, : .


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This message is a reply to:
 Message 4 by RAZD, posted 08-07-2017 4:05 PM RAZD has responded

Replies to this message:
 Message 6 by RAZD, posted 08-19-2017 5:37 PM RAZD has responded

  
RAZD
Member
Posts: 18867
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.6


Message 6 of 9 (817754)
08-19-2017 5:37 PM
Reply to: Message 5 by RAZD
08-12-2017 6:39 AM


The Ages of the Grand Canyon

The Ages of the Grand Canyon

It seems that YECies are drawn to the Grand Canyon like moths to a flame ... there are several common YECie PRATTs regarding the Grand Canyon, including one on how the canyon was formed (see Claim CH581). The concept of the canyon being formed by drainage overflow over the ridge is falsified by the topography north and south of the canyon.

There are two paths that cross the ridge at lower elevations than where the canyon cut through the ridge, one to the north is >3 times as wide as the canyon and one to the south is >2 times as wide as the current canyon rim to rim even though lower than either rim elevation.

There is no evidence of any mass flow of water over either of these paths, certainly nothing on the scale of the Grand Canyon.

As we shall see here, the actual ages of the Grand Canyon at different stages of formation will tell a different story of the formation of the Grand Canyon, one based on facts and objective empirical evidence.

Age and Evolution of the Grand Canyon Revealed by U-Pb Dating of Water Table-Type Speleothems(1)

quote:
The age and evolution of the Grand Canyon have been subjects of great interest and debate since its discovery. We found that cave mammillaries (water table indicator speleothems) from nine sites in the Grand Canyon showed uranium-lead dating evidence for an old western Grand Canyon on the assumption that groundwater table decline rates are equivalent to incision rates. Samples in the western Grand Canyon yielded apparent water table decline rates of 55 to 123 meters per million years over the past 17 million years, in contrast to eastern Grand Canyon samples that yielded much faster rates (166 to 411 meters per million years). Chronology and inferred incision data indicate that the Grand Canyon evolved via headward erosion from west to east, together with late-stage (∼3.7 million years ago) accelerated incision in the eastern block.

The realization that certain speleothems such as mammillary coatings (Fig. 1) form near ground-water tables [herein referred to as water tables (6)], and the fact that many Grand Canyon caves contain mammillary speleothems (7), has allowed us to take advantage of advances in U-Pb and U-series analytical techniques in an effort to make the long-sought chronology possible. For the Grand Canyon area (Fig. 2), there is no better niche than caves to find both clastic and chemical sediments that were deposited before, during, and after the incision of the canyon. Equally important, these cave deposits are located throughout the canyon. Caves are not only well suited to contain these deposits, they also provide an ideal environment that preserves and protects them from weathering. These mammillary coatings in the Grand Canyon caves contain sufficient uranium-lead ratios and yield U-Pb dates that place the water table within the canyon at a particular place and at an absolute time. This allows for the incision history of the Grand Canyon to be reconstructed on the basis of the premise that the timing of this water table descent is coeval with incision of the Colorado Plateau by the Colorado River system.

Mammillary samples were dated by the U-Pb method (11). U-Pb analyses of relatively young carbonate speleothems have recently been shown to be feasible under certain circumstances (12), and concerns with excess 206Pb from initial 234U - 238U isotopic disequilibrium can be resolved by combining U-Pb data with 234U - 238U chronometer data (12, 13): 206Pb data are corrected for 234U excess and 230Th deficiency, and 207Pb data are corrected for 231Pa deficiency (9) (fig. S2). Where U-Pb and 234U chronologies overlap, the two systems give consistent chronology.

Our core data (57 analyses) come from nine mammillary coatings throughout the canyon, referred to as sites 1 to 9 (Fig. 2). Four of these coatings (sites 1 to 4) for the western Grand Canyon, all within 1200 vertical meters above the Colorado River, yield ages of 17.0, 7.6, 3.9, and 2.2 Ma. Five other coatings (sites 5 to 9) are located in the eastern Grand Canyon, all within 950 vertical meters above the river, and have ages of 3.7, 3.4, 2.7, 2.2, and 0.8 Ma. For simplicity and consistency, all apparent water table descent rates are based on a relatively flat water table over time. Our U-Pb ages (Table 1 and table S1) show water table descent rates of 55 to 123 m per million years (My) in the western Grand Canyon and 166 to 411 m/My in the eastern Grand Canyon.

SiteRegion238U/206Pb
age (Ma)
235U/207Pb
age (Ma)
Concordia-
constrained
linear 3D
age (Ma)
Dist.
above
river
(m)
Dist.
from
river
(m)
RMIR
(m
Ma)

error
Abs.
error
Exten-
ded

error
Exten-
ded
Abs.
error
1Grand
Wash
Cliffs
7.53±0.427.1±1.47.55±0.3493038.6277123+6-5+24-18
2Cave B3.8±0.324.3±0.53.87±0.102900.526675+2-2+35-15
3Dry
Canyon
2.17±0.48.1±9.92.17±0.341201.626555+10-7
4Grand
Canyon
Caverns
17.3±1.6029.0±14.016.96±0.83116028.919068+4-3+4-3
5 Gavain
Abyss
2.39±0.776.2±5.92.19±0.4900 5.593411+112-73
6 Tsean
Bida
3.37±0.501.0±16.03.43±0.437264.680212+30-24+134-59
7Butte
Fault
Cave
2.73±0.633.7±7.92.68±0.494452.657166+37-26
8Bedrock
Canyon
0.8±0.120.7±0.30.83±0.053102.132374+22-20
9Shinumo
Creek
Cave
3.5±1.30-1.0±5.23.72±0.809206.694247+68-44+208-78
10Mother
Cave
234U age
= 1.6±0.5
6052.290>300

Sample sites 1 and 4 are situated 42 and 26 km north and south, respectively, of the Colorado River (Fig. 2) and show water table descent rates that have spatial extent just beyond the canyon itself. Our four western data points support a relatively stable slow drop in the water table in the western Grand Canyon over the past 17 My. In contrast, results from the eastern Grand Canyon show distinctly faster water table descent rates, all having U-Pb ages less than 4 Ma (Fig. 3). In addition, one other site in the eastern Grand Canyon could not be dated by U-Pb (excess common Pb) but has a positive &delta234U value. This sample from Mother Cave near Grand Canyon Village (site 10; Fig. 2 and Table 1) has a 234U - 238U age [based on a δ234U initial value of 3000 ± 2500 per mil (‰)] of 1.6 ± ∼0.5, yielding an apparent water table descent rate of >300 m/My; these data provide further evidence of faster eastern Grand Canyon water table descent rates.

Western Grand Canyon incision rates are well constrained at 50 to 75m/My for the last 0.73 My from basalts located within 60 vertical meters above the river (2). Our incision rates representing 100 to 1200 m of incision (55 to 75 m/My, excepting site 1) compare well with those determined from the near-river basalt flows and fill an incision rate history gap representing millions of years. Canyon incision by a smaller river system is the most likely interpretation for the relatively stable long-lasting rate of apparent water table descent (55 to 123 m/My) for the western Grand Canyon. This suggests that the western Grand Canyon has been forming for the past 17 My and has probably progressed slowly headward to the east over that entire period. An older western Grand Canyon fits nicely with Miocene extension and timing of Grand Wash fault activity that may represent uplift of the western edge of the Colorado Plateau just prior to 20 Ma (14) and filling of the Grand Wash trough with sediment coming from the Virgin Mountains to the north and higher topography just to the east (15). A water table descent to the elevation of site 1 (∼1200 m above sea level) indicates that erosion of trough sediments was taking place as early as 7.6 Ma. Our incision rate data would imply that Grand Canyon incision into the Grand Wash fault cliffs incised into the top of the Redwall-Muav aquifer of the Colorado Plateau some time between 16 and 9 Ma. Initiation of deposition of the Miocene-aged, lacustrine, Hualapai limestone [11 to 6 Ma (16, 17)] may have been coeval with, and the result of, the release of carbonate-rich water from the newly truncated Redwall Limestone (14, 18).

The eastern third of the Grand Canyon appears to have undergone fast incision (>166 m/My) and rapid headward erosion starting before 3.7 Ma and likely at 5 to 6 Ma when the Colorado River became fully integrated and through-flowing (17). A previously reported faster incision rate in the eastern Grand Canyon [150 to 230 m/My for the past 0.5 My; river mile 60 (19)] is consistent with our results in that area (140 to 203 m/My) and was compared and attributed to the Hurricane Fault displacement (2). However, our data suggest accelerated headward erosion in the eastern Grand Canyon—whether from simple knick-point propagation, lake overflow (20), or karst capture (18). Marble Canyon mammillaries also indicate fast incision rates. At river miles 57 (site 7) and 32 (site 8), incision rates are 166 and 374 m/My, respectively, and at river mile 38, a speleogenetic gypsum crust yielded a U-series age of 0.15 Ma at 50 m above the river and an incision rate of ≤330 m/My.

Overall, our data argue for an older Grand Canyon that was modified in the late Miocene by a fully integrated Colorado River that accelerated the headward erosion of the eastern Grand Canyon. We found that mammillary calcite is not restricted to large caves in the Redwall and Muav limestones, but also occurs in small fissure-controlled caves in other units such as the overlying Supai Formation. Hundreds of these deposits probably exist throughout the canyon, offering the potential for a reconstruction of the canyon's history, with a resolution perhaps high enough to explain complexities of the canyon's history related to faults, folds, and volcanic and tectonic activity.


The Grand Canyon is at least 3.7 million years old at the eastern end, and at least 17 million years old at the western end, and it formed by headward erosion from west to east.

Floodplain Management SESSION 7 (PowerPoint PPT Presentation)(2)

quote:
Stream Systems on Dynamic Earth


This slideshow presents typical erosion patterns, with a typical "V" shaped canyon formed as the sides erode and collapse into the stream and are carried away. Bands of harder rock cause headcuts when the rock below erodes faster than the bands. These headcuts migrate upstream as the bands erode.

This reflects how the Grand Canyon formed as shown by the evidence above: when a mammillary forms in a cave under the second headcut surface before the first headcut reaches to top, and a later mammillary forms in a cave under the first headcut surface, it shows that the erosion is a slow process.

Rapid high volume flood discharge flow is quite different: it forms wide flat bottomed channels with very little meandering and very different bottom topography.

Channeled Scablands(3)

quote:
The Channeled Scablands are a relatively barren and soil-free landscape on the eastern side of the U.S. state of Washington that was scoured by a series of up to 40 cataclysmic floods; over a 2,000 year period, which were unleashed when a large glacial lake repeatedly drained.[1] These cataclysmic Missoula Floods swept across eastern Washington and down the Columbia River Plateau during the Pleistocene epoch, occurring about 15,000–13,000 years ago.

There are also immense potholes and ripple marks, much larger than those found on ordinary rivers. When these features were first studied, no known theories could explain their origin. The giant current ripples are between 3.3 and 49.2 feet (1 and 15 m) high and are regularly spaced, relatively uniform hills.[3] Vast volumes of flowing water would be required to produce ripple marks of this magnitude, as they are larger-scale versions of the ripple marks found on streambeds that are typically only centimeters high. Large potholes were formed by swirling vortexes of water called kolks scouring and plucking out the bedrock.[4]


And that is only glacial lake overflow -- not a world wide fantasy flood -- and the geography here is nothing like the spires and other stuctures seen in the Grand Canyon.

This makes the YECie scenarios incompatible with the evidence and basic hydraullics. And because it was not formed by any world wide fantasy flood, it means such a flood did not occur in the last 17 million years (such a flood would have destroyed the canyon walls and spires).

The earth is at least 17 million years old (2017) by this data.

Remember: The challenge for old age deniers (especially young earth proponents) is to explain why there is so much consilience from different measurement systems, from different sets of data and from different sources of information ... if the earth is not old?

The earth is very, very, very old. Get used to it.

Enjoy

References

  1. Polyak, V., Hill, C., and Asmerom, Y., "Age and Evolution of the Grand Canyon Revealed by U-Pb Dating of Water Table-Type Speleothems," Science 07 Mar 2008, Vol. 319, Issue 5868, pp. 1377-1380, DOI: 10.1126/science.1151248 online [2017] http://science.sciencemag.org/content/319/5868/1377.full
  2. Reichmuth, D. R., "Floodplain Management SESSION 7," (PowerPoint PPT Presentation), Geomax, online [2017] http://www.powershow.com/...ON_7_powerpoint_ppt_presentation
  3. Anon, "Channeled Scablands," Wikipedia.com (website), last edited 7 August 2017 [2017] https://en.wikipedia.org/wiki/Channeled_Scablands

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 Message 7 by RAZD, posted 08-19-2017 5:44 PM RAZD has responded

  
RAZD
Member
Posts: 18867
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.6


Message 7 of 9 (817755)
08-19-2017 5:44 PM
Reply to: Message 6 by RAZD
08-19-2017 5:37 PM


Talking Coral Heads

Talking Coral Heads

Now we are going to introduce a twist. We've mentioned coral with previous dating mechanisms and we've now been through thorium dating, a common method for dating coral heads. Coral heads put down growth layers just like trees and other organic systems.

Estimating past sea-surface temperatures from corals(1)

quote:
Corals are animals of the phylum Coelenterata, to which also the jellyfish and sea anemones belong. Some species of corals have stony skeletons, consisting almost entirely of calcium carbonate (CaCO3), and the term coral is often applied to the skeletons themselves. Most atolls are built on thick layers of coral residue that accumulated over millions of years on top of submerging volcanoes. There are three kinds of this skeletal material, i.e. plate-like, branching, and "massive". The last is rounded and bulky and proves to be useful for estimating past sea-surface temperatures (SST) in tropical regions (1).

Tropical coral reefs grow mainly where the SST exceeds 18°C, and optimal growth occurs at about 25°C. At 25°C the growth rate of massive corals is about 50% faster than at 18°C. The dependence on temperature means a variation of growth rate with season. In the past there has been confusion in interpreting coral cross-sections, due to uncertainty about the process of coral growth. Some corals appeared to grow fastest in the warmer wet season and others in the cooler dry season.

X-ray examination reveals that massive coral has layers of different density, due to seasonal variations, like the annual rings of tree trunks. Counting of the density layers in large colonies of coral provides annual dating of the layers for several hundreds of years. Massive coral cores of the Porites type on Australia's Great Barrier Reef (GBR) have been dated back to 1479 AD (1). ...


We saw in Part 1 (Biological Counting Systems), Message 20 (Cariaco Basin Varves), that radiometrically dated coral was used in the carbon-14 calibration data, (and we will revisit this in more detail in [msg=12], Carbon-14 Decay Revisited).

IntCal04 Terrestrial Radiocarbon Age Calibration, 0-26 CAL KYR BP(2)

quote:
This paper focuses on the IntCal04 calibration data set for 14C ages of Northern Hemisphere terrestrial samples. However, because 14C measurements of foraminifera from the Cariaco Basin varved sediments and U-series-dated coral are the basis for the terrestrial calibration data set beyond the beginning of the tree rings at 12.4 kyr, we will discuss marine data in brief. ...

So where's the twist? What else can coral tell us that these other systems and mechanisms can't? Those coral layer dates are pretty insignificant compared to the other data, and the carbon-14 calibration curve is already coverd in Part 1, right?

The twist comes from ancient corals. Sure, one can assemble all the coral cores and align them by seasonal variations and piece together a database similar to the tree ring data bases we started with, but as it sits now there are not enough cores to assemble without significant gaps in between (I fully expect a complete database to be assembled over time).

For now we can assemble the bits and pieces, placing the ancient cores by dates derived from radiometric testing (thorium-230 is used for some), and while we can derive similar dates from two or more tests, this is hardly enough to impress people who still have some doubts about radiometric dating methods. Is there something else that will give us an independent confirmation?

The answer is yes, and it comes from an entirely different system based on the astrophysics of the earth-moon system.

Coral Growth and Geochronometry(3)

quote:
The two chief approaches to geochronometry are based on radioactive isotopes and on astronomical data. The most recent estimates 2 of geological time based on the rates of radioactive decay give the Cenozoic a length of 65 million years, the Mesozoic 165 million years, and Palaeozoic 370 million years, and so on. The beginning of the Cambrian is placed about 600 million years ago. To accept these figures is an act of faith that few would have the temerity to refuse to make. The other approach, radically different, involves the astronomical record. Astronomers seem to be generally agreed that while the period of the Earth's revolution around the Sun has been constant, its period of rotation on its polar axis, at present 24 h, has not been constant throughout Earth's history, and that there has been a deceleration attributable to the dissipation of rotational energy by tidal forces on the surface and in the interior, a slow-down of about 2 sec per 100,000 years according to the most recent estimates. It thus appears that the length of the day has been increasing throughout geological time and that the number of days in the year has been decreasing. At, the beginning of the Cambrian the length of the day would have been 21 h (ref. 1). After the first, a second act of faith is easy, and we can develop a simple relation between the geological time-scale and the number of days per year (Fig. 1)

Accepting this relation, in the absence of evidence to the contrary, it now follows that if we can find some means of determining the number of days per year for the different geological periods, we have a ligation between the results of geophysical and astronomical deductions. If we could determine, for example, that the number of days in the Cambrian year was of the order of 420, it would seem to confirm an indicated age of 600 million years based on tidal friction and in turn that since isotopic methods give the same result they too are in harmony. Is it possible to obtain estimates of the number of days per year from data preserved in recent and fossil organisms ? I would like to think so.

... Physiological studies on calcium carbonate secretion in recent corals, first made some years ago by Kawaguti and Sakumotos 6, and recently and more elegantly by Goreau 7, who used the isotope calcium 45, show that in reef corals the rate of calcium carbonate uptake in coral tissues falls at night or in darkness and rises during the day, but the reflexion of this in the skeleton ton has not yet been investigated. A much less-sophisticated approach would be to compare the number of ridges with the annual growth-rate; but this has not been directly tried on living corals in the field. I have tested it indirectly on one or two recent corals the annual linear growth-rate of which is fairly well known, and to my gratification found that the number of ridges on the epitheca, of the living West Indian scleractinian Manicina areolata (Fig. 5) hovers around 360 in the space of a year's growth. This strongly suggests, subject to experimental confirmation, that the growth-lines are diurnal or circadian in nature. It may be noted in passing that they may provide a much more sensitive caliper for measurement of annual growth-rates than the larger yearly simulations.

The next step, of course, is an attempt to determine, the number of growth-lines per annum in fossil corals. Here, as is usually the case, hypothesis is easier than practice. Few fossil corals are sufficiently well preserved to show clearly the supposed diurnal growth-lines, and it is not easy to determine the annual rate. In epithecate recent corals the growth-lines are commonly abraded or corroded even before death of the polyp. The best of the limited fossil material I have examined so far is from the Middle Devonian. of New York and Ontario, especially specimens of Heliophyllum, Eridophllum .(Fig. 6) and Favosites. Diurnal and annual growth-rates vary in the same individual, adding to the complexity, but in every instance there are more than 365 growth -lines per annum. usually about 400, ranging between extremes of 385 and 410. It is probably too much, considering the crudity of these data, to expect a narrower range of values for the number of days in a year in the Middle Devonian; many more measurements will be necessary to refine them.

A few more data may be mentioned: Lophophllidium from the Pennsylvanian (Conemaugh) of western Pennsylvania gave 390 lines per annum, and Caninia from the Pennsylvanian of Texas, 385. These results imply that the number of days a year has decreased with the passage of time since the Devonian, as postulated by astronomers. and hence that values of the isotopic dates of the geophysicists agree well with the astronomical estimates of the age of the Earth. ...


So these samples with diurnal growth rings showing faster spin and more shorter days per year, right in line with astronomical predictions.

Coral-algae metabolism and diurnal changes in the CO2-carbonate system of bulk sea water(4)

quote:
Abstract

Precise measurements were conducted in continuous flow seawater mesocosms located in full sunlight that compared metabolic response of coral, coral-macroalgae and macroalgae systems over a diurnal cycle. Irradiance controlled net photosynthesis (Pnet), which in turn drove net calcification (Gnet), and altered pH. Pnet exerted the dominant control on [CO32−] and aragonite saturation state (Ωarag) over the diel cycle. Dark calcification rate decreased after sunset, reaching zero near midnight followed by an increasing rate that peaked at 03:00 h. Changes in Ωarag and pH lagged behind Gnet throughout the daily cycle by two or more hours. The flux rate Pnet was the primary driver of calcification. Daytime coral metabolism rapidly removes dissolved inorganic carbon (DIC) from the bulk seawater and photosynthesis provides the energy that drives Gnet while increasing the bulk water pH. These relationships result in a correlation between Gnet and Ωarag, with Ωarag as the dependent variable. ...


This confirms how and why there are diurnal growth rings in corals.

Earth's rotation: Change in rotational velocity(5)

quote:
Over millions of years, the Earth's rotation slowed significantly by tidal acceleration through gravitational interactions with the Moon. In this process, angular momentum is slowly transferred to the Moon at a rate proportional to r-6 , where r is the orbital radius of the Moon. This process gradually increased the length of day to its current value and resulted in the moon's being tidally locked with the Earth.

This gradual rotational deceleration is empirically documented with estimates of day lengths obtained from observations of tidal rhythmites and stromatolites; a compilation of these measurements[41] found the length of day to increase steadily from about 21 hours at 600Myr ago[42] to the current 24 hour value. By counting the microscopic lamina that form at higher tides, tidal frequencies (and thus day lengths) can be estimated, much like counting tree rings, though these estimates can be increasingly unreliable at older ages.[43]


And 21 hour days would mean 24x365.24/21 = 417 days per year.

Radioactive dating correlating with astronomical data on the rotation of the earth over time, something that can only happen if the radiometric dates are correct and the astronomical projections for the earth's rotation are correct.

The earth is at least 600 million years old by this data.

Remember: The challenge for old age deniers (especially young earth proponents) is to explain why there is so much consilience from different measurement systems, from different sets of data and from different sources of information ... if the earth is not old?

The earth is very, very, very old. Get used to it.

Enjoy

References

  1. Linacre, E., and Geerts, B., "Estimating past sea-surface temperatures from corals," 11/'97 [2017] http://www-das.uwyo.edu/~geerts/cwx/notes/chap15/coral.html
  2. Reimer, P. J., Baillie, M.G.L., Bard, E., Bayliss, A., Beck, J. W., Bertrand, C. J. H., Blackwell, P. G., Buck, C. E., Burr, G. S., Cutler, K. B., Damon, P. E., Edwards, R. L., Fairbanks, R. G., Friedrich, M., Guilderson, T. P., Hogg, A. G., Hughen, K. A., Kromer, B., McCormac, G., Manning, S., Ramsey, C. B., Reimer, R. W., Remmele, S., Southon, J. R., Stuiver, M., "IntCal04 Terrestrial Radiocarbon Age Calibration, 0-26 CAL KYR BP," Radiocarbon, Vol 46, Nr 3, 2004, p 1029–1058 https://journals.uair.arizona.edu/...icle/download/4167/3592
  3. Wells, J. W., "Coral Growth and Geochronometry," Nature, March 9, 1963 online at [2017] http://freepages.genealogy.rootsweb.ancestr.../...rowth.html
  4. Jokiel​, P. L., Jury, C. P., Rodgers, K. S., "Coral-algae metabolism and diurnal changes in the CO2-carbonate system of bulk sea water," PeerJv.2; 2014, PMC4034600, Published online 2014 May 22. doi: 10.7717/peerj.378 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4034600/
  5. Anon, "Earth's rotation: Change in rotational velocity," Wikipedia.com (website), last edited 14 August 2017 [2017] https://en.wikipedia.org/...on#Change_in_rotational_velocity

we are limited in our ability to understand
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RebelAmerican☆Zen☯Deist
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This message is a reply to:
 Message 6 by RAZD, posted 08-19-2017 5:37 PM RAZD has responded

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 Message 8 by RAZD, posted 08-19-2017 6:04 PM RAZD has responded

  
RAZD
Member
Posts: 18867
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.6


Message 8 of 9 (817756)
08-19-2017 6:04 PM
Reply to: Message 7 by RAZD
08-19-2017 5:44 PM


Oklo Reactors

Oklo Reactors

One common YECie claim is that radioactive decay occurred at different rates in the (immediate) past, or that physical constants were not constant in the (immediate) past. There is no evidence that either of these occurred, and in fact there is evidence that it did not happen.

The Workings of an Ancient Nuclear Reactor(1)

quote:
In May 1972 a worker at a nuclear fuel–processing plant in France noticed something suspicious. He had been conducting a routine analysis of uranium derived from a seemingly ordinary source of ore. As is the case with all natural uranium, the material under study contained three isotopes— that is to say, three forms with differing atomic masses: uranium 238, the most abundant variety; uranium 234, the rarest; and uranium 235, the isotope that is coveted because it can sustain a nuclear chain reaction. Elsewhere in the earth’s crust, on the moon and even in meteorites, uranium 235 atoms make up 0.720 percent of the total. But in these samples, which came from the Oklo deposit in Gabon (a former French colony in west equatorial Africa), uranium 235 constituted just 0.717 percent. That tiny discrepancy was enough to alert French scientists that something strange had happened. Further analyses showed that ore from at least one part of the mine was far short on uranium 235: some 200 kilograms appeared to be missing— enough to make half a dozen or so nuclear bombs.

... In 1953 George W. Wetherill of the University of California at Los Angeles and Mark G. Inghram of the University of Chicago pointed out that some uranium deposits might have once operated as natural versions of the nuclear fission reactors that were then becoming popular. Shortly thereafter, Paul K. Kuroda, a chemist from the University of Arkansas, calculated what it would take for a uraniumore body spontaneously to undergo selfsustained fission. In this process, a stray neutron causes a uranium 235 nucleus to split, which gives off more neutrons, causing others of these atoms to break apart in a nuclear chain reaction.

Kuroda’s first condition was that the size of the uranium deposit should exceed the average length that fission-inducing neutrons travel, about two thirds of a meter. This requirement helps to ensure that the neutrons given off by one fissioning nucleus are absorbed by another before escaping from the uranium vein.

A second prerequisite is that uranium 235 must be present in sufficient abundance. Today even the most massive and concentrated uranium deposit cannot become a nuclear reactor, because the uranium 235 concentration, at less than 1 percent, is just too low. But this isotope is radioactive and decays about six times faster than does uranium 238, which indicates that the fissile fraction was much higher in the distant past. For example, two billion years ago (about when the Oklo deposit formed) uranium 235 must have constituted approximately 3 percent, which is roughly the level provided artificially in the enriched uranium used to fuel most nuclear power stations.

The third important ingredient is a neutron “moderator,” a substance that can slow the neutrons given off when a uranium nucleus splits so that they are more apt to induce other uranium nuclei to break apart. Finally, there should be no significant amounts of boron, lithium or other so-called poisons, which absorb neutrons and would thus bring any nuclear reaction to a swift halt.

Amazingly, the actual conditions that prevailed two billion years ago in what researchers eventually determined to be 16 separate areas within the Oklo and adjacent Okelobondo uranium mines were very close to what Kuroda outlined. These zones were all identified decades ago. But only recently did my colleagues and I finally clarify major details of what exactly went on inside one of those ancient reactors.

Physicists confirmed the basic idea that natural fission reactions were responsible for the depletion in uranium 235 at Oklo quite soon after the anomalous uranium was discovered. Indisputable proof came from an examination of the new, lighter elements created when a heavy nucleus is broken in two. The abundance of these fission products proved so high that no other conclusion could be drawn. A nuclear chain reaction very much like the one that Enrico Fermi and his colleagues famously demonstrated in 1942 had certainly taken place, all on its own and some two billion years before.

After my colleagues and I had worked out in a general way how the observed set of xenon isotopes was created inside the aluminum phosphate grains, we attempted to model the process mathematically. This exercise revealed much about the timing of reactor operation, with all xenon isotopes providing pretty much the same answer. The Oklo reactor we studied had switched “on” for 30 minutes and “off” for at least 2.5 hours. The pattern is not unlike what one sees in some geysers, which slowly heat up, boil off their supply of groundwater in a spectacular display, refill, and repeat the cycle, day in and day out, year after year. This similarity supports the notion not only that groundwater passing through the Oklo deposit was a neutron moderator but also that its boiling away at times accounted for the self-regulation that protected these natural reactors from destruction. In this regard, it was extremely effective, allowing not a single meltdown or explosion during hundreds of thousands of years.


Note that the existence of natural reactors was predicted in 1953 by George W. Wetherill (of the University of California at Los Angeles) and Mark G. Inghram (of the University of Chicago) and that the conditions for this were described by Paul K. Kuroda (of the University of Arkansas), before the Oklo natural reactors were discovered.

This evidence of the Oklo natural reactors occurring in Gabon (Africa), where 235U spontaneously began to fission, due to the concentration of uranium-235 existing there in the past, is entirely within the processes used today in modern nuclear reactors. When we look at the byproducts we see the same formations that we see today from man-made reactors.

Natural nuclear fission reactor: Relation to the atomic fine-structure constant(2)

quote:
A natural nuclear fission reactor is a uranium deposit where self-sustaining nuclear chain reactions have occurred. This can be examined by analysis of isotope ratios. The existence of this phenomenon was discovered in 1972 at Oklo in Gabon by French physicist Francis Perrin. The conditions under which a natural nuclear reactor could exist had been predicted in 1956 by Paul Kazuo Kuroda.[1] The conditions found were very similar to what was predicted.

Oklo is the only known location for this in the world and consists of 16 sites at which self-sustaining nuclear fission reactions took place approximately 1.7 billion years ago, and ran for a few hundred thousand years, averaging probably less than 100 kW of thermal power during that time.[2][3][4]

The natural reactor of Oklo has been used to check if the atomic fine-structure constant α might have changed over the past 2 billion years. That is because α influences the rate of various nuclear reactions. For example, 149Sm captures a neutron to become 150Sm, and since the rate of neutron capture depends on the value of α, the ratio of the two samarium isotopes in samples from Oklo can be used to calculate the value of α from 2 billion years ago.

Several studies have analysed the relative concentrations of radioactive isotopes left behind at Oklo, and most have concluded that nuclear reactions then were much the same as they are today, which implies α was the same too.[10][11]


This means we can accurately date these reactors.

The Natural Nuclear Reactor at Oklo: a Comparison with Modern Nuclear Reactors (PDF)(3)

quote:
The absence of 236U (t1/2 = 2.342 x l07a) indicates that induced fission stopped at least 108 years ago. Dating of the strata in which the reactor is found indicates an age of approximately 1.8 Gy (Cowan, 1976). At that time, 235U had an abundance of approximately 3%, owing to its shorter half-life relative to 233U (t1/2=7.04 x l08 yrs and 4.468 x l09 yrs, respectively). This paper discusses briefly the geologic setting of the Gabon reactor and compares its nuclear characteristics with those of modern, manmade nuclear reactors in terms of fuel loading, geometry, neutron flux, power, and uranium enrichment.

... The formation in which the deposits reside was deposited about 1.74 (+0.20) billion years ago (Ga). At this time,235U had a relative abundance of approximately 3%.

A total of 16 reactor zones have been found in the primary location, and another reactor zone identified about 20 km away (the Bangombé reactor). Current thinking is that a zone of petroleum formation produced an oxygen-free zone because oxygen in groundwater would have been removed by chemical reactions with the petroleum. Uranium, which is fairly highly soluble in oxygenated waters, is insoluble in anoxic waters, so the uranium precipitated out of solution as it crossed the oxidation/reduction front near the petroleum deposits (Janeszek 1999). This is what formed the reactor zones.

Nuclear reactors produce power by controlled induced splitting (fission) of fissionable atoms. ... The nuclear fission process is more efficient with low energy (thermal) neutrons, although fast fission of both 235U and 238U does occur in the fuel.

Since fission neutrons are produced with high energies, they must be slowed down (thermalized) in a moderator in order to be effective at inducing fission. This moderator is typically normal water, ... Submerging the fuel in the moderator increases reactor efficiency (and decreases required fuel loading) by reflecting escaping neutrons back into the core, allowing them to participate in the fission process.


So these reactors are 1.74x109 years old and operated in similar fashion to modern man-made reactors.

Oklo: natural fission reactor program. Progress report, April 1-June 30, 1979. [U-Ru dating](4)

quote:
nalyses of samples from the Oklo site have shown that 99Tc and fissiogenic ruthenium appear to have migrated upwards with respect to the natural fission reactors. This migration was measured over distances of 2 to 10 meters from the reactor zones. The native material of the basal conglomerate was shown not to be a source of the radiogenic Pb incorporated in the stratum. Thus, the radiogenic Pb must have come from the Oklo uranium ore bodies. A sensitive technique was developed for mass spectrometric analyses of ruthenium at the nanogram level. Measurements with this technique permitted validation of a U-Ru age dating procedure by comparison with U-Pb dates from the same ores. Measured yields of 101Ru, 102Ru, and 104Ru from spontaneous fission 238U were found to agree with previous estimates. Analyses of two samples from the Morro do Ferro thorium deposit in Brazil cannot be used to define a precise time of ore formation. The data can be used to infer relative migration of thorium with respect to lead during the past 290 x 106 years. 2 figures, 5 tables.

A second dating method confirms the first.

Fine-structure constant: Past rate of change(5)

quote:
In physics, the fine-structure constant, also known as Sommerfeld's constant, commonly denoted α (the Greek letter alpha), is a fundamental physical constant characterizing the strength of the electromagnetic interaction between elementary charged particles. It is related to the elementary charge e, which characterizes the strength of the coupling of an elementary charged particle with the electromagnetic field, ...

In electrostatic cgs units, the unit of electric charge, the statcoulomb, is defined so that the Coulomb constant, ke, or the permittivity factor, ... is 1 and dimensionless. Then the expression of the fine-structure constant, as commonly found in older physics literature, becomes

Physicists have pondered whether the fine-structure constant is in fact constant, or whether its value differs by location and over time. A varying α has been proposed as a way of solving problems in cosmology and astrophysics.[13][14][15][16] String theory and other proposals for going beyond the Standard Model of particle physics have led to theoretical interest in whether the accepted physical constants (not just &alpha) actually vary.

In the experiments below, delta-alpha, or Δα, represents the change in alpha over time, which can be computed by αprev − αnow. If the fine-structure constant really is a constant, then any experiment should show that

or be as close to zero as that experiment can measure. Any value far away from zero would indicate that α does change over time. So far, most experimental data is consistent with α being constant.

The first experimenters to test whether the fine-structure constant might actually vary examined the spectral lines of distant astronomical objects and the products of radioactive decay in the Oklo natural nuclear fission reactor. Their findings were consistent with no variation in the fine-structure constant between these two vastly separated locations and times.[17][18][19][20][21][22]

Improved technology at the dawn of the 21st century made it possible to probe the value of α at much larger distances and to a much greater accuracy. In 1999, a team led by John K. Webb of the University of New South Wales claimed the first detection of a variation in α.[23][24][25][26] Using the Keck telescopes and a data set of 128 quasars at redshifts 0.5 < z < 3, Webb et al. found that their spectra were consistent with a slight increase in α over the last 10–12 billion years. Specifically, they found that

In other words, they measured the value to be somewhere between -0.0000047 and -0.0000067. This is a very small value, nearly zero ...


So thus far the most it could have changed is 0.00067%, which is negligable for any effect on the radiometric age dating methods.

This means there has been little change in the way radioactive elements break down in the last 1.74 billion years.

We can also note that just a very small increase in neutron energy would allow 238U to undergo similar spontaneous fission, and that deposits existing today would be sufficient in concentration to allow this to happen. As these concentrations have decreased with the decay that has already occurred, it is evident that no such increase in neutron energy ever occurred in the past.

Changes to physical constants need a cause.

Changes to physical constants have an effect.

The conceptual system that best ties all these together in a way that fits the observed evidence, with known cause and effect, is the current scientific system, with constant constants, and an earth with an old age, old enough for the decay chain byproducts to form and decay.

Based on this information alone we can conclude:

  • The theoretical basis for radiometric dating is precise, accurate and valid.
  • Radiometric methods are valid - at least as far back as 1.74 billion years ago.
  • That there was no magical change in the behavior of radioactive materials in the last 1.74 billion years.

The earth is at least 1.74 billion years old by this precise and accurate data.

Remember: The challenge for old age deniers (especially young earth proponents) is to explain why there is so much consilience from different measurement systems, from different sets of data and from different sources of information ... if the earth is not old?

The earth is very, very, very old. Get used to it.

Enjoy

References

  1. Meshik, A. P., "The Workings of an Ancient Nuclear Reactor," Scientific American, October 2005, online version [2017] https://www.scientificamerican.com/...ncient-nuclear-reactor
  2. Anon, "Natural nuclear fission reactor: Relation to the atomic fine-structure constant," Wikipedia.com (website), last edited 7 July 2017 [2017] https://en.wikipedia.org/...e_atomic_fine-structure_constant
  3. Karam, A., "The Natural Nuclear Reactor at Oklo: a Comparison with Modern Nuclear Reactors," on-line PDF, 1996, Last revised 4/16/05 [2017] http://www.physics.isu.edu/radinf/Files/Okloreactor.pdf
  4. Norris, A.E., "Oklo: natural fission reactor program. Progress report, April 1-June 30, 1979. [U-Ru dating]," United States: N. p., 1979. Print. on-line [2017] https://www.osti.gov/scitech/biblio/5887619
  5. Anon, "Fine-structure constant: Past rate of change," Wikipedia.com (website), last edited 15 August 2017 [2017] https://en.wikipedia.org/...ure_constant#Past_rate_of_change

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This message is a reply to:
 Message 7 by RAZD, posted 08-19-2017 5:44 PM RAZD has responded

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 Message 9 by RAZD, posted 08-20-2017 7:41 AM RAZD has not yet responded

  
RAZD
Member
Posts: 18867
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Joined: 03-14-2004
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Message 9 of 9 (817773)
08-20-2017 7:41 AM
Reply to: Message 8 by RAZD
08-19-2017 6:04 PM


A String of Pearls

A String of Pearls

A string of pearls is made with pearls of a consistency in size and luster. We've touched on radiometric dating methods a couple of times now, in relation to how they correlate with the layer counting systems to show their validity, and we've discussed how the physical constants are valid throughout the various radiometric methods discussed. Now we are going to discuss consistency in radiometric methods.

Radiometric Dating, A Christian Perspective: The Radiometric Clocks (page 3)(1)

quote:
There are now well over forty different radiometric dating techniques, each based on a different radioactive isotope.

The term isotope subdivides elements into groups of atoms that have the same atomic weight. For example carbon has isotopes of weight 12, 13, and 14 times the mass of a nucleon, referred to as carbon-12, carbon-13, or carbon-14 (abbreviated as 12C, 13C, 14C). It is only the carbon-14 isotope that is radioactive. ...

A partial list of the parent and daughter isotopes and the decay half-lives is given in Table I. Notice the large range in the half-lives. Isotopes with long half-lives decay very slowly, and so are useful for dating correspondingly ancient events. ...

Radioactive Isotope (Parent)Product (Daughter)Half-Life (Years)
Samarium-147Neodymium-143106 billion
Rubidium-87Strontium-8748.8 billion
Rhenium-187Osmium-18742 billion
Lutetium-176Hafnium-17638 billion
Thorium-232Lead-20814 billion
Uranium-238Lead-2064.5 billion
Potassium-40Argon-401.26 billion
Uranium-235Lead-2070.7 billion
Beryllium-10Boron-101.52 million
Chlorine-36Argon-36300,000
Carbon-14Nitrogen-145715
Uranium-234Thorium-230248,000
Thorium-230Radium-22675,400

The half-lives have all been measured directly either by using a radiation detector to count the number of atoms decaying in a given amount of time from a known amount of the parent material, or by measuring the ratio of daughter to parent atoms in a sample that originally consisted completely of parent atoms. Work on radiometric dating first started shortly after the turn of the 20th century, but progress was relatively slow before the late forties. However, by now we have had over fifty years to measure and re-measure the half-lives for many of the dating techniques. Very precise counting of the decay events or the daughter atoms can be done, so while the number of, say, rhenium-187 atoms decaying in 50 years is a very small fraction of the total, the resulting osmium-187 atoms can be very precisely counted. For example, recall that only one gram of material contains over 1021 (1 with 21 zeros behind) atoms. Even if only one trillionth of the atoms decay in one year, this is still millions of decays, each of which can be counted by a radiation detector!

The uncertainties on the half-lives given in the table are all very small. All of the half-lives are known to better than about two percent except for rhenium (5%), lutetium (3%), and beryllium (3%). There is no evidence of any of the half-lives changing over time. In fact, as discussed below, they have been observed to not change at all over hundreds of thousands of years.


The amounts of the isotopes are measured by very accurate and precise methods, and this means that the ages calculated are as accurate as the measurements and the half-lives, which means they are precise and accurate within 1% to 5% error.

There are other correlations between radiometric dating methods, all showing broad consistency in results when properly applied:

Are Radioactive Dating Methods Consistent With Each Other?(2)

quote:
To check, we need one single event which has been dated by several methods. A nice example is the Triassic multiple-impact event, which formed a 4500-kilometer-long chain of huge craters. (There must have been a train of big objects from space, which hit the spinning earth, one by one, across several hours. Much like the way comet Shoemaker-Levy hit Jupiter in 1994.)

Here are the five confirmed craters:

CraterCountryDiameterMillion Years AgoDating Method
ManicouaganCanada100 km214±1U-Pb on zircons
Saint MartinCanada40 km219±32 Rb/Sr
RochechouartFrance25 km214±8Ar/Ar laser spot fusion
ObolonUkraine15 km215±25stratigraphic
Red WingUSA9 km200±25stratigraphic

"Stratigraphic" dating means that the crater itself has not been dated. Instead, the rock strata above and below the crater was dated. (By now, the Red Wing crater is under 1.5 kilometers of sediment.)

The table shows five datings that are consistent with each other. However, there is a sixth dating involved: the one for drawing the map.

Today, the continents are moving about one inch a year. This is a simple fact which can be measured by anyone with good GPS equipment. So, in 214 million years, the continents could have moved three thousand miles. To get a map of that past world, geologists did K/Ar datings of ancient lava flows. As the article below shows, the three main craters form a dead straight line on that map.

These dates were obtained by several different radioactive methods, on rocks of several different kinds, by geologists from four different countries. But the dates are consistent. That is the usual case, so the article didn't bother to comment on it.


The ages from this string of pearls all overlap within the margins of error for each method - an actual age of 214x106 years BP (1950 CE) is consistent with each one. This consilience provides strong additional validation for these dating methods. Even the least accurate method (stratigrapic) has an error of ±25 million years in 214 million years is an error of ±11.6%, which is very repeatable and precise, with moderate accuracy.

But that is not all the evidence of accuracy and precision to come from meteorites.

Radiometric Dating Does Work!(3)

quote:
It is rare for a study involving radiometric dating to contain a single determination of age. Usually determinations of age are repeated to avoid laboratory errors, are obtained on more than one rock unit or more than one mineral from a rock unit in order to provide a cross-check, or are evaluated using other geologic information that can be used to test and corroborate the radiometric ages. Scientists who use radiometric dating typically use every means at their disposal to check, recheck, and verify their results, and the more important the results the more they are apt to be checked and rechecked by others. As a result, it is nearly impossible to be completely fooled by a good set of radiometric age data collected as part of a well-designed experiment.

The purpose of this paper is to describe briefly a few typical radiometric dating studies, out of hundreds of possible examples documented in the scientific literature, in which the ages are validated by other available information. I have selected four examples from recent literature, mostly studies involving my work and that of a few close colleagues because it was easy to do so. I could have selected many more examples but then this would have turned into a book rather than the intended short paper.

The Ages of Meteorites

Meteorites, most of which are fragments of asteroids, are very interesting objects to study because they provide important evidence about the age, composition, and history of the early solar system. There are many types of meteorites. Some are from primitive asteroids whose material is little modified since they formed from the early solar nebula. Others are from larger asteroids that got hot enough to melt and send lava flows to the surface. A few are even from the Moon and Mars. The most primitive type of meteorites are called chondrites, because they contain little spheres of olivine crystals known as chondrules. Because of their importance, meteorites have been extensively dated radiometrically; the vast majority appear to be 4.4–4.6 Ga (billion years) old. Some meteorites, because of their mineralogy, can be dated by more than one radiometric dating technique, which provides scientists with a powerful check of the validity of the results. The results from three meteorites are shown in Table 1. Many more, plus a discussion of the different types of meteorites and their origins, can be found in Dalrymple (1991).

There are 3 important things to know about the ages in Table 1. The first is that each meteorite was dated by more than one laboratory — Allende by 2 laboratories, Guarena by 2 laboratories, and St Severin by four laboratories. This pretty much eliminates any significant laboratory biases or any major analytical mistakes. The second thing is that some of the results have been repeated using the same technique, which is another check against analytical errors. The third is that all three meteorites were dated by more than one method — two methods each for Allende and Guarena, and four methods for St Severin. This is extremely powerful verification of the validity of both the theory and practice of radiometric dating. In the case of St Severin, for example, we have 4 different natural clocks (actually 5, for the Pb-Pb method involves 2 different radioactive uranium isotopes), each running at a different rate and each using elements that respond to chemical and physical conditions in much different ways. And yet, they all give the same result to within a few percent. Is this a remarkable coincidence? Scientists have concluded that it is not; it is instead a consequence of the fact that radiometric dating actually works and works quite well. Creationists who wants to dispute the conclusion that primitive meteorites, and therefore the solar system, are about 4.5 Ga old certainly have their work cut out for them!

The K-T Tektites

One of the most exciting and important scientific findings in decades was the 1980 discovery that a large asteroid, about 10 kilometers diameter, struck the earth at the end of the Cretaceous Period. The collision threw many tons of debris into the atmosphere and possibly led to the extinction of the dinosaurs and many other life forms. The fallout from this enormous impact, including shocked quartz and high concentrations of the element iridium, has been found in sedimentary rocks at more than 100 locations worldwide at the precise stratigraphic location of the Cretaceous-Tertiary (K-T) boundary (Alvarez and Asaro 1990; Alvarez 1998). We now know that the impact site is located on the Yucatan Peninsula. Measuring the age of this impact event independently of the stratigraphic evidence is an obvious test for radiometric methods, and a number of scientists in laboratories around the world set to work.

In addition to shocked quartz grains and high concentrations of iridium, the K-T impact produced tektites, which are small glass spherules that form from rock that is instantaneously melted by a large impact. The K-T tektites were ejected into the atmosphere and deposited some distance away. Tektites are easily recognizable and form in no other way, so the discovery of a sedimentary bed (the Beloc Formation) in Haiti that contained tektites and that, from fossil evidence, coincided with the K-T boundary provided an obvious candidate for dating. Scientists from the US Geological Survey were the first to obtain radiometric ages for the tektites and laboratories in Berkeley, Stanford, Canada, and France soon followed suit. The results from all of the laboratories were remarkably consistent with the measured ages ranging only from 64.4 to 65.1 Ma (Table 2). Similar tektites were also found in Mexico, and the Berkeley lab found that they were the same age as the Haiti tektites. But the story doesn’t end there.

The K-T boundary is recorded in numerous sedimentary beds around the world. The Z-coal, the Ferris coal, and the Nevis coal in Montana and Saskatchewan all occur immediately above the K-T boundary. Numerous thin beds of volcanic ash occur within these coals just centimeters above the K-T boundary, and some of these ash beds contain minerals that can be dated radiometrically. Ash beds from each of these coals have been dated by 40Ar/39Ar, K-Ar, Rb-Sr, and U-Pb methods in several laboratories in the US and Canada. Since both the ash beds and the tektites occur either at or very near the K-T boundary, as determined by diagnostic fossils, the tektites and the ash beds should be very nearly the same age, and they are (Table 2).

There are several important things to note about these results. First, the Cretaceous and Tertiary periods were defined by geologists in the early 1800s. The boundary between these periods (the K-T boundary) is marked by an abrupt change in fossils found in sedimentary rocks worldwide. Its exact location in the stratigraphic column at any locality has nothing to do with radiometric dating — it is located by careful study of the fossils and the rocks that contain them, and nothing more. Second, the radiometric age measurements, 187 of them, were made on 3 different minerals and on glass by 3 distinctly different dating methods (K-Ar and 40Ar/39Ar are technical variations that use the same parent-daughter decay scheme), each involving different elements with different half-lives. Furthermore, the dating was done in 6 different laboratories and the materials were collected from 5 different locations in the Western Hemisphere. And yet the results are the same within analytical error. If radiometric dating didn’t work then such beautifully consistent results would not be possible.


Once again the consilience in the results from all these different methods provides very strong validation for these dating methods being both accurate and precise.

Based on this information alone we can conclude:

  • The theoretical basis for radiometric dating is precise, accurate and valid.
  • The half-lives are accurate and precise and give consistent results.
  • The different radiometric methods are all equally valid - at least as far back as 4.5 billion years ago.
  • That there was no magical change in the behavior of radioactive materials in the last 4.5 billion years.

Simply put, radiometric age measurement is an accurate, precise and valid method for determining the age of objects.

Remember: The challenge for old age deniers (especially young earth proponents) is to explain why there is so much consilience from different measurement systems, from different sets of data and from different sources of information ... if the earth is not old?

The earth is very, very, very old. Get used to it.

Enjoy

References

  1. Weins, R.C., "Radiometric Dating A Christian Perspective: The Radiometric Clocks," (page 3), The American Scientific Affiliation: A Fellowship of Christians in Scientists. First edition 1994; revised version 2002. [2017] http://www.asa3.org/ASA/resources/Wiens.html#page%203
  2. Lindsay, D., "Are Radioactive Dating Methods Consistent With Each Other?" Don Lindsay Archive (website). Last modified: 2 April 2000. [2017] http://www.don-lindsay-archive.org/...tion/crater_chain.html
  3. Dalrymple, G. Brent "Radiometeric Dating Does Work!" National Center for Science Education. Originally published in RNCSE 20 (3): 14-19. The version on the web might differ slightly from the print publication. [2017] https://ncse.com/...ry-resource/radiometric-dating-does-work

Edited by RAZD, : .


we are limited in our ability to understand
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... to learn ... to think ... to live ... to laugh ...
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 Message 8 by RAZD, posted 08-19-2017 6:04 PM RAZD has not yet responded

  
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