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25

Yes, the age of the Earth is about 4.5 billion years (4,500 million years). Your linked articles describes well how it was formed and how we know about it. The uncertainty is less than 1% and depends partly on the radiometric dating methods and partly on the definitions. Sometimes the age is said to be 4.567 Ga, that might be a little too exact number to ...


9

The oldest undisputed fossil are Stromatolites, bacterial mats, the oldest of which are dated ay 3.7 billion years ago. The key term here is undisputed, there are other possible fossils but it is very hard to have certainty with chemical or cellular fossils. The oldest uncertain fossils trace back to 4.28 billion years and are possible bacteria trapped in ...


8

As noted in the comments the wikipedia articles (at the time this question was submitted) are contradictory. There are quite a few steps to the logic of how argon-argon dating works but none are too complicated, although I won't go into all of the possible interferences. One thing to keep in mind is that high-precision isotope measurements always measure ...


7

A good chronometer is one that satisfies the following conditions: We know exactly how much it had of something when it began We know exactly the rate of the accumulation of the thing, and the rate is constant. For example, U-Pb dating in zircon is an excellent chronometer. We know exactly how much Pb is in zircon when it crystallises (= none) and we know ...


6

The cited paper, and ones like it, are young earth creationist nonsense. The Geoscience Research Institute is an arm of the Seventh Day Adventists, whose official position is that "in a recent six-day creation the Lord made “the heavens and the earth, the sea, and all that is in them” and rested on the seventh day." This is a central tenet of Seventh Day ...


4

It does seem like it's impossible to know unless you have additional information. However, I think there is a hint in there. See this white halo around the intrusion? My guess (and I could be wrong here) is that it's not there for artistic reasons but rather it's there to provide a very strong hint. My feeling that this is some kind of metamorphosed contact ...


4

First of all, you shouldn't take creationists seriously; like flat earthists, their views are totally out of touch with reality. Rates of radioactive decay have been tested many times in the laboratory and found to be accurate. However, there have been some instances where a substantial change of temperature or the formation of a chemical compound involving ...


4

I run an argon lab which does also K-Ar measurements. The sample amount depends on the age because you need enough signal strength to measure the radiogenic argon component precisely. Young rocks have very low 40Ar* and to get enough volts on the detector you need more sample. Having the incorrect amount is akin to trying to measure micrometers with a ...


3

From Australian Government- Geoscience AustraliaAustralian Stratigraphic Units Database: Panorama Formation: Paleoarchean min age: 3427 MA Age method: isotopic, U/Pb-Pb/Pb ion probe Dresser Formation: Min Age: Ma: 3477 Age method: inferred, overlying unit McPhee Formation: Min Age: 3477 Age method: isotopic, U/Pb-Pb/Pb ion probe


3

It sounds like there are two primary ones: No, these are not the two "primary ones". The method used depends on what you are dating, and what age you expect it to be. Radiocarbon dating is relevant to things younger than a few tens of thousands of years, and it's only relevant for things that were living (or growing), and incorporated atmospheric carbon. ...


3

Suppose you purify a sample of uranium 238, removing all of the lead. Half of those U-238 atoms will have decayed into lead 4.468 billion years from now. If the lead is removed from that half-uranium/half-lead sample 4.468 billion years from now, half of the U-238 atoms in that purified sample will have decayed into lead in yet another 4.468 billion years. ...


3

The reliability is dependent on the quality, (for instance is the mineral reworked or porous and thus prone to contamination), and size of the sample, (small samples result in poorer measurement). There is also of course the date range issue, use a sample that is too old or too new and the amount of each element is so tiny it can't accurately be measured. ...


2

What exactly are you trying to measure? some of the great North American and Andean batholiths have cooling histories of at least 20 million years, and maybe more than 50 million years. It is perhaps inappropriate to think of the crystallization process as having a single date. Phenocrysts near the top of the pluton are cooler, but may sink to deeper levels ...


1

Many of your questions are answered in this question and associated answers: Why is Earth's age given by dating meteorites rather than its own rocks? To add to some of your other questions: Wouldn't radioactive decay have already been occurring in all of those meteorites long before they hit earth or our moon? Yes. We have an assumption that the ...


1

ScienceMag says: Rather than damaging the fossils by dating them directly, the team looked to the sediments in which they were found. They discovered pieces of charcoal in sediments at similar depths, and considered those to be proxies for the ages of the fossils themselves. The charcoal bits were dated to around 19,000 and 13,000 to 11,000 years before ...


1

If the fossils, or some of them, were as you describe them with no mineral replacement of the original material, then it would seem that C14 dating would be relevant for the youngest bones at least. If they had original material with adequate carbon in it,C14 is such an obvious method that they must have tried it, or had some very good reason not to. C14 is, ...


1

Firstly, there are simplified analytical cases that even undergrad students are able to master that inform us how decay rates generally depend on other natural constants and available energy levels. Those cases, while not describing full reality, give us important information, namely that if a decay constant would not be constant, then either other ...


1

Potassium 40 has a half life of 1,300,000,000 years, which means that within that time half of the 11 percent which you refer to will have decayed to form Argon 40. Potassium 40 has two modes of decay, which is unusual for a radioactive isotope. Only 11 percent of it becomes argon 40, the remaining 89 percent decays by a different mode and becomes Calcium ...


1

There are huge datasets of geochronology available in the published literature. Unfortunately there is not one single database because the task is daunting (there are several thousand geochronology labs in the world which typically produce hundreds of ages per year). Some papers discussing how data should be (and often are) reported are these, for example : ...


1

How many have been validated by historic calibration, and what proportion (if any) yielded inconsistent results? Often with an item that they want tested, a specific date isn't available so calibration isn't possible, but calibration can be done when dates are known. Tree rings are most common and (though I've not read of this being done), samples from ...


1

The better site for sample collection would be the accessible site where it's possible to pick up a sample. Unless you have a drill rig or an excavator, you are limited to what's exposed. If you still have access to several zones of the pluton, take all of them. The more samples you have, the better it is. By choosing not to sample a certain zone you might ...


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