Questions tagged [dating]
The dating tag has no usage guidance.
38 questions
2
votes
0
answers
73
views
what is pMC percent modern carbon?
In material about carbon dating I see a lot of results expressed in pMC. For example I saw a 14C/C ratio of .12 pMC. My understanding is that the amount of 14C in carbon is about one trillionth. I'...
- 143
2
votes
1
answer
116
views
creationism and helium
One of the creationist claims for a young Earth is that Helium is found in Zircons, which are dated to be over 100,000 years old. They say no Helium should be left because it would have diffused out ...
- 143
0
votes
3
answers
221
views
How is limestone dated?
I know that limestone is found in a variety of geological formations, and I thought it would be useful if some knowledgeable people weighed in on how the ages of these layers are determined.
- 101
1
vote
1
answer
245
views
How important or necessary are assumptions when it comes to radiometric dating?
So when I say radiometric dating, I'm specifically referring to U-Pb, Ar-K and Rb-SR rather than C14 as I think these are more accurate when it comes to corroborating an older earth. I've heard people ...
- 11
2
votes
1
answer
2k
views
Does anyone know more about Creationist stunts where they get labs to date Triassic Coal with C14 and recent Mt St Helens lava with K-Ar
A Creationists keeps responding to me insisting that radioactive dating is invalid because someone dated a 1986 lava flow from St Helens to 250,000 yrs, and they got a C14 date on Triassic Coal from ...
- 29
2
votes
0
answers
44
views
Variability in 4.5 billion year age of earth based on radioactive dating of meteorites?
Which meteorites in particular give an age of 4.5 billion years and which isotopes are used for radioactive analysis? Is there much variability if different meteorites or isotopes are used?
- 121
6
votes
1
answer
360
views
Did geologists determine the age of rocks and fossils before the advent of modern scientific dating methods?
Did geologists determine the age of rocks and fossils before the advent of modern scientific dating methods such as radiometric, electron spin resonance and thermoluminescence?
If they did, does ...
- 165
2
votes
1
answer
177
views
Does water affect radiometric dating?
When radiometric dating, would water affect the measured age of old rocks ?
Specifically would water affect Uranium-238 to Lead-206 dating of Zircon crystals?
Would it affect the lead since it’s ...
- 211
8
votes
2
answers
2k
views
Do lead 206 and other daughter isotopes occur naturally?
I am reading studies about the age of the earth and U-238 to Pb-206 comes up a lot.
My question is:
In meteorites, or really anywhere, is lead 206 natural or does it always come from radioactive decay?...
- 211
2
votes
2
answers
487
views
What methods do geologists employ to detemine the age of a petroleum deposit?
Petroleum is not considered a rock, but it is formed by a process, so it has an age.
What methods do geologists employ to determine the age of a petroleum deposit?
user20559
1
vote
0
answers
36
views
Dating recent skeletons with radiometric dating techniques
Can we use radiometric dating techniques on recent skeletons from, say, around the year 2000 and so on and get the same result as the recorded date of death of the owner of the skeleton? If yes (or no)...
- 111
1
vote
2
answers
53
views
Why are thrust faults older than normal faults in the Himalayan-Tibetan plateau?
In the Himalayan-Tibetan plateau, both normal and thrust faults are observed. Geological
age dating suggests thrust faults are older (before 18-20 Ma) than the normal faults (after 18-20
Ma). Explain ...
- 113
7
votes
4
answers
587
views
Why does radioactive dating work on specific rocks?
As I understand it, radioactive dating measures time by what portion of a radioactive isotope has decayed. Weren't all the natural radioactive isotopes created during the solar system's formation? So ...
- 173
2
votes
1
answer
91
views
In radiometric isochron dating why is at t=0 D*/Dref=const but P/Dref not?
I am a physics graduate and trying to understand one of the assumptions made for isochron dating of rocks: at crystallization time of the rock, $t=0$, the ratio of the parent isotope to a stable ...
- 173
4
votes
1
answer
72
views
Does the heat of reentry affect the reliability of radiometric dating of meteorites?
This may be more of an age-dating question. When a meteorite travels through the Earth's atmosphere, I assume that it gets really hot. Is the temperature of reentry hot enough to affect the ...
- 1,055
1
vote
2
answers
356
views
How was the onset of the Cambrian period dated?
What dating method was used to determine the beginning of the Cambrian, and what was its margin of error? Was only one fossil dated, or were a number of similar fossils used?
- 4,711
6
votes
4
answers
300
views
Has there ever been a case where we have found what appears to be a prehistoric fossil but have no way of dating it?
I find that when ever I learn of a new fossil, the age of said fossil is always mentioned. This perplexes me given how intuitively rare it seems to have radioactive material to date a formation. I ...
- 179
1
vote
1
answer
991
views
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? [duplicate]
How can the radiometric dating of different meteorites determine the age of the earth? Wouldn't radioactive decay have already been occurring in all of those meteorites long before they hit earth? ...
- 13
3
votes
0
answers
61
views
Calibration of OSL dates to calender year dates
I am trying to utilize a function that uses calibrated $^{14}C$ dates. However, my data consists of OSL dates, not $^{14}C$. Searching google scholars did not provide any useful results. Since OSL ...
- 131
1
vote
2
answers
130
views
Can we carbon-date the remains of homo floresiensis found in 2003?
According to the Wikipedia article on the species Homo floresiensis, the remains discovered in 2003 consist of unfossilized bones. I would assume that means they are still composed of the original ...
- 185
1
vote
2
answers
422
views
How do we know the rate of decay for radiometric dating is constant?
http://www.purdue.edu/newsroom/research/2010/100830FischbachJenkinsDec.html
The link above talks about a research paper from Purdue University that the researchers had detected slight fluctuations in ...
- 169
2
votes
1
answer
202
views
Potassum-Argon Dating and Proportions of Daughter Products in Potassium 40 Decay Channel
So Potassium 40 decays in such a way that roughly 89% of it becomes Calcium 40 and 11% of it becomes Argon 40. When they list these figures are they implying that after 1 half-life, of the 50% of the ...
- 303
5
votes
0
answers
72
views
Age of the Earth without radiometric dating?
It is common knowledge that age of the Earth is roughly 4.5 billion years. Radiometric dating of meteorites (which were formed during the formation of Earth) and earliest rocks on Earth have both ...
- 293
2
votes
2
answers
332
views
Radiometric dating data sets
I am in the process of learning what sort of data is collected with radiometric dating techniques, used for absolute dating. It sounds like there are two primary ones:
Radiocarbon dating (~50k year ...
- 289
7
votes
1
answer
2k
views
What is the oldest fossil on Earth?
What is the oldest fossil ever found on Earth? Where and when was it found? What was the oldest fossil with a brain with 2 hemispheres ever found?
- 1
3
votes
1
answer
481
views
Giem's article on carbon dating
I don't want to start any controversy. I'm just curious about what could professional geologists say about this paper, and what is it's current scientific status, since I couldn't find any serious ...
- 141
4
votes
0
answers
393
views
Puzzle using relative dating principles
This isn't directly looking at a real life ecological example kind of thing, but it requires knowledge of relative dating, so I thought I would come here.
Here is what was told:
-"Worms" (curved ...
3
votes
1
answer
310
views
How to sample for K-Ar dating?
How much sample of volcanic rock is required to undertake a K-Ar date measurement, and does it matter if the rock contains vesicles? Are there tricks of the trade to get a good sample?
- 14.3k
4
votes
2
answers
98
views
Source of Dresser Formation 3.5 Ga dating
I've seen many papers and sites that give the dating of Australia's Dresser Formation as 3.5 Ga (variously 3.48 or 3.49 Ga), but I can't seem to find the source of this.
Where does the dating come ...
- 43
16
votes
1
answer
5k
views
How old is the Earth?
According to most articles I've read online, the estimated age of Earth is 4.5 billion years.
Question: How old is the Earth?
So I actually want to confirm that this is the case. Maybe there are ...
- 263
8
votes
1
answer
887
views
Why is ocean salinity not a good chronometer?
In 1910, George Becker published The Age of the Earth, in which he used the sodium accumulation rate in the ocean to estimate the earth's age as 50 to 70 million years. We now know through various ...
- 183
7
votes
1
answer
207
views
How good is K-Ar dating?
I don't doubt that K-Ar dating of rocks is a sound method, but in discussions with skeptics it would be good to know just how reliable exactly? For example, has K-Ar been cross-checked with other rock ...
- 14.3k
7
votes
1
answer
3k
views
How does argon-argon dating work - need a simple but not-wrong explanation
The Washington Post article Scientists discover hundreds of footprints left at the dawn of modern humanity describes the geological dating of stratified layers of mud by analyzing and dating minerals ...
- 6,904
4
votes
1
answer
526
views
Relative dating of intrusion
I am quite new to geology and have a realtive dating problem which I am a bit unsure of. I know very well the principle of superposition, principle of cross-cutting, etc., but am still a little bit ...
- 143
3
votes
1
answer
289
views
Why can isotopes reflect the age of the Earth rather than the age of the supernova that created them?
Radiometric dating is based on heavier elements decaying into lighter elements, for example uranium decaying to lead. But wasn't all uranium in the Solar System created in one or more supernova? And ...
- 693
6
votes
0
answers
108
views
Dating fluvial terraces with $^{10}\rm{Be}$
I've completed part A of the question below.
Dating fluvial terraces with $^{10}\rm{Be}$
One way to determine the age of an alluvial deposit is to collect a series of samples from a range of depths, ...
- 161
4
votes
2
answers
253
views
Relative dating of granite pluton
In selecting a sample for age-dating of a granite pluton, which site is a better site to collect a sample from, the centre, top or side? Why was this site a better choice? Which dating method would ...
- 41
4
votes
1
answer
141
views
How many $\ce{^{14}C}$ measurements have been made?
I know that the upper limit of radiocarbon dating is typically about 60,000 years, but how many radiocarbon dates have actually been measured? As of October 2015, how many $^{14}\ce C$ (radiocarbon) ...
- 14.3k