# Tag Info

Accepted

### How old is the Earth?

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 ...
• 5,896

### Do lead 206 and other daughter isotopes occur naturally?

While lead 206 does occur naturally, unless a zircon (a zirconium silicate crystal) is contaminated with lead or has been around a long time, it will contain no lead. Zirconium, uranium, and thorium ...
• 20k
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### What is the oldest fossil on Earth?

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 ...
• 6,465

### Do lead 206 and other daughter isotopes occur naturally?

The four stable isotopes of lead and their relative abundance on Earth are: 204Pb (1.4%), 206Pb (24.1%), 207Pb (22.1%) and 208Pb (52.4%). Lead-204 is a primordial nuclide and is not a radiogenic ...
• 12.7k

### Has there ever been a case where we have found what appears to be a prehistoric fossil but have no way of dating it?

The short answer is no, because we always have some constraint of how old something is. Sometimes we have fossils with large date error bars, and often we do not know for how long that species ...
• 1,015
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### How does argon-argon dating work - need a simple but not-wrong explanation

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 ...
• 4,319
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### Why is ocean salinity not a good chronometer?

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 ...
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### Giem's article on carbon dating

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 ...
• 20k
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### In radiometric isochron dating why is at t=0 D*/Dref=const but P/Dref not?

1) D* (radiogenic isotope) and Dref (stable reference isotope) are two isotopes of the same element. P is the radioactive parent of D*, and is a different element. Chemical fractionation between P and ...
• 771
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### How to sample for K-Ar dating?

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 ...
• 771
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### Relative dating of intrusion

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 ...
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### How do we know the rate of decay for radiometric dating is constant?

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 ...
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### How was the onset of the Cambrian period dated?

Fossils are only in very rare cases dated directly, because they do not contain sufficient radioactive isotopes for dating. Most geological periods are first and foremost defined by biostratigraphy- ...
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### Why does radioactive dating work on specific rocks?

There are other, mostly chemical processes which alter the isotope ratios. Isotope dating uses a combination of them. This is why it can not be used always, for any radioactive isotopes, only in ...
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### Did geologists determine the age of rocks and fossils before the advent of modern scientific dating methods?

The approach adopted by Charles Lyell (and other writers in a similar timeframe), in his book 'Principles of Geology' which was first published in the 1830s was to look at processes in the modern ...
• 1,206

### Has there ever been a case where we have found what appears to be a prehistoric fossil but have no way of dating it?

Yes it does happen, and we know when and why it happens. The most common reason is because of bad collection methods. Some times laypeople collect fossils without recording where or when the collected ...
• 6,465
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### Why does radioactive dating work on specific rocks?

Weren't all the natural radioactive isotopes created during the formation of the solar system? The half life of carbon 14 is 5730 years, orders of magnitude less than the age of the solar system. ...
• 20k
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### Does the heat of reentry affect the reliability of radiometric dating of meteorites?

Current consensus says heat does not affect the rate of radioactive decay and if it does it is due to time dilation, the effect of whihc is very small. Thus the heating of meteorites as they enter ...
• 20.3k
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### Source of Dresser Formation 3.5 Ga dating

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 ...
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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 ...
• 22.2k
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### Why can isotopes reflect the age of the Earth rather than the age of the supernova that created them?

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/...
• 20k

### How good is K-Ar dating?

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). ...
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### Does water affect radiometric dating?

No, not really. In simple terms, to be soluble in water, Pb must be in contact with it. But most of Pb is stored within the Zircon lattice, where water cannot diffuse through. For example, many ...
• 31

### Relative dating of granite pluton

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 ...
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### How can radiometric dating of meteorites determine the age of the earth? Wouldn't this only determine the age of the decaying nuclide in each rock?

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: ...
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### Can we carbon-date the remains of homo floresiensis found in 2003?

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 ...
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### Why does radioactive dating work on specific rocks?

Radioactive dating works on specific isotopes we use for specific time frames. Rubidium–strontium dating methods (because this substance has a half life of 50 billion years) to date extremely old ...
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### What methods do geologists employ to detemine the age of a petroleum deposit?

Crude oil is a product of partial degradation of organic matter, e.g. of plants that lived long time ago. During photosynthesis, they constantly incorporate carbon (from $\ce{CO2}$) to accumulate ...
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1 vote
Accepted

### Why are thrust faults older than normal faults in the Himalayan-Tibetan plateau?

In line with what strawberry-sunshine has answered, and to put it into more layman terms, after a compressive episode there's a distensive one. Imagine you have a volume of sand, and you are ...
1 vote

### Has there ever been a case where we have found what appears to be a prehistoric fossil but have no way of dating it?

To answer your question, "...surely there have been cases where we have found new fossils that we have no way of knowing the age?", the short answer is yes. Prior to modern radiometric ...
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