Questions tagged [geochronology]
The geochronology tag has no usage guidance.
25
questions
1
vote
1
answer
92
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
5
votes
0
answers
45
views
Why are there unnamed Cambrian Stages?
What is it about Stages 2,3,4, and 10 (as well as Series 2) in the Cambrian Period that has left solely them unnamed? Will this be resolved in time, or is it a relic of the historical naming process, ...
6
votes
1
answer
809
views
How old is Steptoe Butte (WA, USA)?
Steptoe Butte is a quartzite "island" in the sea of loess known as the Palouse Hills, in eastern Washington and western Idaho in the United States. According to Wikipedia:
The rock that ...
- 7,709
2
votes
1
answer
126
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
3
votes
3
answers
388
views
References for Newton's & Kepler's age of the Earth calculations
"Everybody knows" that Newton and Kepler calculated the age of the Earth. My problem is that, whilst "everybody knows" this, no-one gives a reference that I can read for myself.
If,...
- 31
7
votes
2
answers
334
views
Unwarranted claim of higher degree of accuracy in zircon geochronology
The uncertainty in the half life of uranium-238 is stated at 0.05% [1]. The same paper gives the date 251.941 myr ± 31 kyr.
251.941 $\times$ 0.05% = 125 kyr.
How are the authors justified in ...
- 293
3
votes
0
answers
32
views
Ages of the Andean Cordilleras
What is the timing of the rise of the Andes, especially if focused on the chronosequence differences among (Western, Central, Eastern) Cordilleras uplift.
- 83
2
votes
2
answers
287
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 ...
- 269
6
votes
1
answer
159
views
Historically, how did the total amount of salt / NaCl on Earth develop?
After reading this question about the origin of NaCl on Earth, I'm wondering: How did the amount of NaCl develop historically? Is it a more or less linear growth until today? Was it such a linear ...
- 257
1
vote
1
answer
344
views
Is astrochronology a proper method?
Wikipedia's definition of astrochronology is:
"Astrochronology is the dating of sedimentary units by calibration
with astronomically tuned timescales, such as Milankovic cycles,1[2]
or even ...
user12525
3
votes
0
answers
95
views
How exactly did Patterson determine the parameters in his Pb–Pb geochron equations?
In his famous paper Age of meteorites and the earth (1956), Patterson uses the following expressions:
Which I assume are the same as:
$$ \left(\frac{Pb^{206}}{Pb^{204}}\right)_P = \left(\frac{Pb^{...
- 241
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
2
votes
0
answers
129
views
How should core-rim detrital zircon ages be reported in a sedimentary provenance study?
I understand this might be drifting into the black hole of subjectivity but I would like to know if anyone knows if there is a generally accepted practice. If one has a detrital zircon with a core age ...
- 316
1
vote
1
answer
96
views
Would you see a correlation between detrital zircon age and grain shape?
If one was to quantify the shape (particularly roundness) of detrital zircon grains, would there be a correlation between the age of the detrital zircon grains and their shape? For example, if the ...
- 316
2
votes
0
answers
26
views
Can zircons be analysed by the (U+Th)/He after being ablated for analysis of U-Pb?
I have zircons that have been mounted in a resin block. They have been polished to approximately half way through the zircons (as is convention) and they have been ablated to attain the U-Pb or Pb-Pb ...
- 316
4
votes
2
answers
240
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
6
votes
1
answer
1k
views
How do scientists measure the age of old animal remains?
The remains of a mammoth were recently unearthed in a Michigan farmer’s field [1]. This find could provide new information on the activity of early humans in the area, experts at the University of ...
- 153
5
votes
2
answers
634
views
Age of fossils found in rocks
I have heard the claim by creationists that geologists date rocks by the fossils they contain and date fossils by the rocks in which they are found. This supposedly invalidates radiometric ages ...
- 1,952
7
votes
1
answer
4k
views
Newton's estimate of the age of the Earth
I was reading many articles about estimates of the age of the Earth throughout the ages. I was dumbfounded when I read that Newton, arguably one of the greatest scientists ever to have ‘calculated’ ...
- 1,952
12
votes
3
answers
433
views
Nuclear testing and the Anthropocene, a chemostratigraphic link?
The Anthropocene is described by Wikipedia as
an informal geologic chronological term for the proposed epoch that began when human activities had a significant global impact on the Earth's ...
user889
22
votes
2
answers
7k
views
What is the origin of the ocean's salt?
We know we cannot live without salt, but an investigation into the origins of ocean's salt leads one to believe that this issue is not fully resolved yet.
What geological phenomenon caused the earth ...
user1066
36
votes
5
answers
3k
views
How do we know the asteroids formed at the same time as earth?
In continuation of the question Why is Earth's age given by dating meteorites rather than its own rocks?, what evidence do we have that the asteroids indeed formed at the same time as earth? Is there ...
- 827
13
votes
3
answers
459
views
How to determine how long ago a rock was broken?
I know that there are techniques that help scientists determine the age of a rock. But is it also possible to determine how long ago a rock was broken? For example, how could we date the formation of ...
- 231
12
votes
1
answer
282
views
How to interpret the use of late and early Tertiary from older literature?
When reading older papers how should I interpret the use of "Late Tertiary" and "Early Tertiary"? Would these periods equate to Paleogene and Neogene, or was there a different accepted boundary age ...
- 541
9
votes
2
answers
837
views
How do scientists determine the absolute or 'chronometric' date of fossils?
Absolute dating is the process of determining an approximate computed age of something like a fossil. How does that work?
- 2,852