Summations Only

Playing devil's advocate, don't these assumptions completely undermine radiometric dating? If most of the daughter element dissipates, won't samples date much older than they should? And isn't it impossible to determine that hasn't happened?And even if that problem were solved, if decay rates were greater in the past, won't samples again date much older than they should? And isn't it impossible to know past decay rates?Given this, isn't it appropriate to ignore radiometric dates?

If they are not controlled. Possible. But if we see patterns developing, we start to find ways to avoid problems. For instance, we know that pyroxene retains argon from the magma, based on experience. So, what do we do? We avoid pyroxene in sampling of the material. Of course, YECs don't do this. Do you mean, 'do we have absolute certainty?' Of course not.But we do have very precise measurements repeated time after time which give us confidence that the numbers are pretty much correct.We also have data on trapping temperatures for daughter isotopes in certain minerals and other support for a lack of daughter isotopes in some minerals at formation.Basically, if there were significant discrepancies, there would be no patterns in the data. We would have just a random set of numbers.The fact that we have corroborating data from different, independent methods is about the best confirmation available. No. If decay rates were different, we wouldn't have the ratios that exist in the Oklo natural reactor. This goes beyond my expertise, but someone here has explained it before.Essentially, we know of no crustal conditions that would change the decay rate of a radionuclide. If there were such, we would see something amiss in the data. And does any YEC think about the consequences of rapid decay that would be millions of times faster than what we know in order to get billions or years down to thousands? A nuclear physicist could explain it, but I'd say that the earth would be little more than a slag heap drifting through space. I think there is ample evidence that this is not the case. If one has no curiosity or desire to understand the patterns, sure.The fact that old ages explain a lot of what we see in the geological record is a pretty good indicator that it is as accurate as we can expect from any analytical procedure.Add all this up and it's pretty clear that radiometric dating is a valid method for determining the absolute timing of geological events.If anyone has specific examples, we could discuss them.

Just to help out, I will mention that there is independent evidence that decay rates were not greater in the past along several lines on inquiry.1) Direct observation of decay rates from at least 170,000 years ago via observation of distant supernova.2) Experimental results indicating that decay rates are essentially unaffected by extreme heat, pressure, magnetism etc.3) Quantum mechanical modeling of atom which relates decay rates to things like the speed of light which is also verified to be constant over time based on a number of lines of inquiry, including the fact that such things affect processes like nuclear reactions. See cited results discussed by edge on natural nuclear reactors.4) Formation of halos which require a very specific energy level of the alpha particle emitted by polonium. A changed decay rate would directly affect the energy level. This particular method provides verification of constant decay rates over millions of years.5) RATE study conducted by YEC folks which raised the issue of the effect of the release of heat at rates large enough to reduce dating from billions of years even into the 100 thousand year range. No such heat effects exist. The effect on speeding up the decay rate of potassium would have produced radiation that killed all of life. So this rapid rate would have to have preceded life on earth making it a useless argument for someone who believes all life was created in just two-three days.I assume that it was okay to respond to your message. I'll also point out that there is an entire thread devoted to this particular question. That thread has had one creationist since it opened six weeks ago, and that post did not deal with the topic. Edited by NoNukes, : No reason given.Edited by Adminnemooseus, : Added some blank lines.

Shouldn't they date much younger than they actually are? Daughter isotopes build up over time. If they dissipate, then this would result in an underestimate of age. As mentioned above, we have direct observations of past decay rates in cosmological events. The decay rates are governed by the fundamental nuclear forces (weak and strong). Changes in these fundamental forces would have far ranging consequences, including fusion rates in stars, power output from stars, changes in the ratio of ring radii within uranium radiohalos, changes in the ratio of products in naturally occurring nuclear reactors (e.g. Oklo), differences in dates using different types of decay and different isotope pairs, and a whole host of other easily observable and testable consequences.As it is, we can find thousands and thousands of observations supporting constant decay rates in the past. For example, we can consistently get the same date for the same geologic feature using K/Ar, U/Pb, and Rb/Sr dating, even though all three use different types of decay mechanisms. Such a thing wouldn't be possible if decay rates were different in the past because they would alter rates different for different types of decay and isotopes.

The Hawaiian-Emperor seamounts and other seamount chains show an increase in dates as you go from one end to the other, consistent with what would be expected from the rate of tectonic movement over a hot spot. This would seem to be strong evidence of RMD accuracy.Further, ash from the eruption of Toba is dated around 74,000 years ago, and it is found at the correct area in ice cores.
In a core from the bed of Lake Malawi, it is found at 28 metres, about 50% further than where C14 runs out at 50,000 years.Then there are tree rings and Lake Suigetsu to support C14 dating.So far I have not seen any Creation "Science" attempt to explain these consistencies.

In addition to the heat and lethal radiation problem, AND has to say why it affected the moon, because the moon rocks all date old, and the Sun, because spectroscopic studies show it does not have short lived radio-isotopes, and ditto for most stars.
After they explain that, YEC can then tell us why the Moon, Mercury, Mars etc are covered in craters.

And am trying to minimize the "Dates and Dating" forum type stuff.Adminnemooseus

So we have YECs claiming that the earth's rocks are all the same age; c6000 years.But we have multiple, different and independent dating methods which says that they are not, all of which must be wrong in different ways for their daft ideas to be true.And the different dating methods all corroborate each other, which would be impossible if they were all broken.This just piles impossibilities upon each other.And it ignores other evidence - lack of genetic bottleneck in all living species, lack of fossil sorting mechanism, lack of flood evidence etc etc.The human mind's ability to deceive itself is quite extraordinary.

You should also add that we have evidence for the assumptions used.Unlike what happens in Creationism, those assumptions in science are not wild guesses being pulled out of some random anus.Edited by Pressie, : No reason given.

No, in the rarely-used-today simplistic methods such as K-Ar, they will date much younger than they really are. In the more sophisticated methods either no date will be produced or the correct date will be produced. No, the most widely used methods such as Ar-Ar and U-Pb detect that occurrence and often produce a valid date anyway. It is not impossible to know past decay rates. Radiometric decay depends on the most fundamental properties of the Universe, and any significant change at any time after the first microsecond or so after the big bang would be detectable in other measurements.If decay were accelerated enough to fit a YEC time frame there would be subtle traces left. There would be no water left, the surface of the Earth would be molten, and there would be no life other than possible some thermophilic bacteria.Edited by JonF, : No reason given.

Thank you for the clarifications about assumptions used in radiometric dating. Trying to summarize

• Assumption 1: The sample has not been compromised in a way that has altered the concentrations of parent and daughter elements.
  ​
  The most common risk is probably escape of daughter element, which as someone noted causes younger, not older, dates. Where sample integrity is in question other dating methods can be employed and the correspondence between methods checked. So while a scientist *could* merely assume his sample's parent/daughter concentrations haven't been compromised, in reality that assumption is only made when warranted, and over the course of decades so many radiometric measurements using so many different methods have been made of so many samples from so many regions as to leave no doubt of the world's great antiquity, especially when considering whether the world is hundreds of millions of years old or just thousands.
  ​
• Assumption 2: The rates of radiometric decay have not changed.
  ​
  This might properly have been labeled an assumption a century ago, but not for a very long time since. It's been verified nine ways from Sunday.

Arguments based upon radiometric dating that "The Geologic Timescale is Fiction" should at this point, 1200 messages into the discussion, be specific and fact based.

There's something important missing from #1.U-Pb and Ar-Ar include an internal check on the premise of no significant material lost or gained by taking multiple measurements on one sample. Ar-Ar heats the sample to progressively higher temperature until it's vaporized, measuring the argon released at each step. U-Pb measures the isotopic ratios at different places even on a weentsy sample (measurement volume as low as 10μm diameter and 1μm deep). Different "dates" from these individual measurements indicate the system has not been closed or there was extra daughter isotope at solidification.Even when the system is not closed or, U-Pb and Ar-Ar often produce a valid date. E.g. in the tour-de-force dating of the eruption of Vesuvius in 79 AD by Ar-Ar at the Berkeley Geochronological Laboratory they detected the presence of "excess argon"; argon that was trapped at solidification. They got the correct date. Plain K-Ar would have produced a date that was too old.Edited by JonF, : No reason given.

I'm not too sure what you mean by the word "dissipates". Could you explain what you mean with the word "dissipates"?

Not really. Crystals at formation under conditions on earth can't incorporate inert gases into the crystal lattices. Basic chemistry.Edited by Pressie, : No reason given.Edited by Pressie, : No reason given.

True but misleading. Inert gases can be physically trapped at solidification, e.g. pillow lava which forms an impermeable shell almost immediately after contacting water.