Age of Grand Canyon and Cave Speleothems

I have a friend to thank for originally bringing this information to my attention.From Just a moment...Science 7 March 2008:
Vol. 319 no. 5868 pp. 1377-1380
DOI: 10.1126/science.1151248Age and Evolution of the Grand Canyon Revealed by U-Pb Dating of Water Table-Type Speleothems^(a)by Victor Polyak*, Carol Hill and Yemane Asmerom

quote:

---

Abstract

​

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.

---

(Note that they are not talking about biological evolution, but the gradual development of the canyon by geological processes.)AlsoHow to Date the Grand Canyon: Go With the Flow | WIRED

quote:

---

It turns out that the time stamps were there all along. They were just hidden away inside the hundreds of caves inside the Grand Canyon's walls. Strange formations known as mammilary coatings -- named for their vague resemblance to breasts -- line some of the cave walls. Mammilary coatings form on the walls of caves that are submerged just below the water table. As the Colorado River sliced deeper down into the Colorado Plateau, the water table gradually dropped. Mammilary coatings marked the river's fall. And as mammilary coatings form, they also happen to trap a lot of uranium. By measuring their age, scientists can measure how long ago they were near the water table.

​

Three geologists from the University of New Mexico have explored caves along the Grand Canyon, ranging from the very bottom to the rim. In this week's issue of Science, they report that the highest caves have mammilary coatings dating back about 17 million years, and the lowest ones date to about 800,000 years. And all the caves between the top and bottom have the intermediate ages you’d expect. By measuring the distance from the rim to the caves, the geologists were then able to estimate how fast the Colorado River carved the canyon. The downstream end of the canyon formed first, and only later did the upstream end catch up. These new measurements show that even as the river sank down into the earth, the earth itself rose, lifted by hot rock welling up through the crust

---

Here is creationist Kent Hovind and his (bad) argument^(b) for how the Grand Canyon was made:
https://www.youtube.com/watch?v=ze5A2pua1E4The dating information above says two things that invalidate the creationist concept that the canyon was formed by flood waters in a few days or weeks as they drained away, slicing into and through the ridge:

1. The canyon formed from west to east, while the creationist model would form from east to west (eroding the top of the barrier to the drainage flow first), and
2. The canyon took at least 16 million years to form according to radiometric dating (17x10^{^6} - 8x10^{^5}).

The evidence that the canyon formed from west to east is independent of the validity of Uranium-Lead dating, it just depends on the measured levels of Uranium and Lead without any age calculation:

• soluble Uranium is captured in the formation of the speleotherm\mammilaries,
• Lead is not soluble in water and so would not be deposited in the speleotherm\mammilaries
• Uranium turns into lead, not vice-versa
• The speleotherm\mammilaries form after the caves have been formed as they are deposits on the cave walls
• Higher ratios of Lead/Uranium therefore are due to greater age of the speleotherm\mammilaries, and thus so are the locations where they are found.

We can also discuss the validity of Uranium-Lead dating with reference to:
Are Uranium Halos the best evidence of (a) an old earth AND (b) constant physics?Enjoy^(a) - Speleothem Definition & Meaning | Dictionary.com ^(b) - Note that I have shown in previous threads why Hovind's explanation is bogus and doesn't work by his own argument that water does not flow uphill -- where the Grand Canyon crosses the ridge is not the lowest point of the ridge, but up on a slope between two lower points, so if he was correct then the canyon would be in a different location.Edited by RAZD, : linkEdited by RAZD, : x10Edited by RAZD, : titleEdited by RAZD, : added definition for speleothem

quote:

---

Where I am starting is from Dr Wiens:
Radiometric Dating

​

quote:

---

13. "Radiation halos" in rocks prove that the Earth was young.

​

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.

---

(bold added for empHASis, part deleted not about uranium halos)

​

Thus when you have isotopes decaying into other isotopes by alpha decay, 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.

​

Very simply put, if you change the decay rate, you change the decay energy, and the diameter of the halo changes.

​

The existence of (common) uranium halos then 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.

---

And in relation to the OP we can also focus on the accuracy of Uranium-Lead dating techniques:From Radiometric DatingRadiometric Dating
A Christian Perspectiveby Dr. Roger C. Wiens

quote:

---

Uranium-Lead and related techniques. The uranium-lead method is the longest-used dating method. It was first used in 1907, about a century ago. The uranium-lead system is more complicated than other parent-daughter systems; it is actually several dating methods put together. Natural uranium consists primarily of two isotopes, U-235 and U-238, and these isotopes decay with different half-lives to produce lead-207 and lead-206, respectively. In addition, lead-208 is produced by thorium-232. Only one isotope of lead, lead-204, is not radiogenic. The uranium-lead system has an interesting complication: none of the lead isotopes is produced directly from the uranium and thorium. Each decays through a series of relatively short-lived radioactive elements that each decay to a lighter element, finally ending up at lead. Since these half-lives are so short compared to U-238, U-235, and thorium-232, they generally do not affect the overall dating scheme. The result is that one can obtain three independent estimates of the age of a rock by measuring the lead isotopes and their parent isotopes. Long-term dating based on the U-238, U-235, and thorium-232 will be discussed briefly here; dating based on some of the shorter-lived intermediate isotopes is discussed later.

​

The uranium-lead system in its simpler forms, using U-238, U-235, and thorium-232, has proved to be less reliable than many of the other dating systems. This is because both uranium and lead are less easily retained in many of the minerals in which they are found. Yet the fact that there are three dating systems all in one allows scientists to easily determine whether the system has been disturbed or not. Using slightly more complicated mathematics, different combinations of the lead isotopes and parent isotopes can be plotted in such a way as to minimize the effects of lead loss. One of these techniques is called the lead-lead technique because it determines the ages from the lead isotopes alone. Some of these techniques allow scientists to chart at what points in time metamorphic heating events have occurred, which is also of significant interest to geologists.

---

Note that lead loss from the speleothems would result in younger age errors, so the corrected results would be older.Enjoy.

The reason is simple: the ridge that is supposedly breached during run-off from the flood is LOWER to the south and the north of the canyon location.Here is the objective empirical data that you can see with your own eyes: Google Maps (Linking to the map does not work, so you will need to click on the link above. Make sure it shows "Terrain" to indicate the topology.)The dark areas are higher than the lighter areas. According to Hovind (and physics) water does not willingly flow uphill, so it would have flowed over one of the lower sections of the ridge (north or south) and the canyon would be in a different location.Enjoy.

From Speleothems - DesertUSA

quote:

---

Slightly acidic groundwater in limestone regions gradually dissolves passages and caverns in the underground rock. Geologists call this karst topography.

​

Speleothems are cave features created after the underground chamber has been formed. They are a result of slow-moving water, usually containing calcium carbonate, which has been dissolved from the limestone where the cave was formed. When this water enters the cave, a chemical change causes the calcium carbonate to precipitate (harden), creating all manner of cave formations and features -- speleothems.

​

Calcite is the stable form of the widely distributed mineral calcium carbonate (CaCO3). Calcite is the primary mineral component of speleothems as well as limestone, the sedimentary rock in which most caves are formed.

​

Mammilary or Cloud: Carbonate coatings that form underwater in cave pools, around projections and rocks lining the pool, whose water is super-saturated with calcium carbonate.

---

From Paleoclimatology: Speleothems

quote:

---

Paleoclimatology: Written in the Earth
by Holli Riebeek design by Robert Simmon June 28, 2005

​

Speleothems: Cave rocks

​

A deep cavern dips into the New Mexico desert, shielding spiky icicle-like rocks that hang from the ceiling and the rounded columns that grow from the floor in a myriad of shapes. One of the world’s largest underground chambers, the Carlsbad Cavern is resplendent in the intricate finery of the rock formations that form there. Beyond their breath-taking beauty, the formations in Carlsbad and the more than 100 other caves in the area provide a record of rainfall in the southwestern United States.

​

Tucked away inside the Earth, the rocks are protected from the weathering and large-scale erosion that taints other land-based climate records. As water runs through the ground, it picks up minerals, the most common of which is calcium carbonate. When the mineral-rich water drips into caves, it leaves behind solid mineral depositsthe same solid material that forms white spots on water faucets or glass dishes. The mineral deposits accumulate in the well-known icicle-shaped rock on the ceiling, a stalactite, and in a mound on the floor where the drip lands, a stalagmite. Less well known, water deposits can also dry in a flat slab called a flowstone.

​

Geologists refer to the mineral formations in caves as speleothems. While the water flows, the speleothems grow in thin, shiny layers. The amount of growth is an indicator of how much ground water dripped into the cave. Little growth might indicate a drought, just as rapid growth could point to heavy precipitation. When the speleothems stop growing, the outside becomes dirty and eroded in places, giving it a dull appearance. A growing speleothem looks smooth and wet.

​

​

Scientists can date the layers in the speleothem by measuring how much uranium, a radioactive element, has decayed. Uranium from the surrounding bedrock seeps into the water and forms a carbonate that becomes part of each layer of the speleothem as it forms. Uranium decays into thorium, which sticks to the clay in the bedrock instead of seeping into ground water and from there into the speleothem. As a result, the newest layers of a growing speleothem typically contain no thorium.

​

Over time uranium predictably turns into thorium, so scientists can tell how old a layer is by measuring the ratio of uranium to thorium. ...

---

And, as we have seen in the OP, the thorium decays into lead, so Uranium-Lead dating can also be used.The Uranium inclusion can thus be used to accurately date when any particular layer of the speleothem was formed.Enjoy.

Thread copied to the Age of Grand Canyon and Cave Speleothems thread in the Geology and the Great Flood forum, this copy of the thread has been closed.