Cosmogenic isotope surface exposure dating

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Here’s an example: The lines are contours of burial time in Myr. This is the foundation of the method of cosmogenic-nuclide burial dating.

So, basically, in the Al-26/Be-10 two-nuclide diagram (let’s not use “banana diagram” any more…historically, it probably should be called a “Lal-Klein-Nishiizumi diagram,” although that is a bit cumbersome), exposure goes to the right and burial goes down. The problem arises when other nuclides are involved.

This is represented by a trajectory that goes down and to the left, as shown above in the Granger example.

So samples that are “below the banana” have experienced both a period of exposure and a period of burial.

If you are reading this, you are probably familiar with the two-nuclide diagram commonly used to represent paired Be-10 and Al-26 data: This example is from a review article by Darryl Granger from 2006 (in GSA Special Paper 415) that gives a good description of what the diagram is and how it is supposed to work.

cosmogenic isotope surface exposure dating-8

So, again, exposure goes to the right and burial goes down. Although I have not made a systematic historiographic study of this phenomenon, I believe that the European style is largely just due to the fact that the “Cosmo Calc” software put together by Pieter Vermeesch does it this way. Nearly all the two-nuclide diagrams in the existing literature involve the normal implementation of the Al-26/Be-10 diagram, so anyone familiar with this literature expects exposure to go to the right on a tw0-nuclide diagram, and burial to go down.

Here we show how to combine surface-exposure-dating and burial-dating techniques in the same profile to get more accurate age results and to constrain the extent of pre-depositional burial periods.

In one kilogram of soil, the potassium-40 amounts to an average 370 Bq of radiation, with a typical range of 100–700 Bq; the others each contribute some 25 Bq, with typical ranges of 10–50 Bq (7–50 Bq for the It is well known that some plants, called hyperaccumulators, are able to absorb and concentrate metals within their tissues; iodine was first isolated from seaweed in France, which suggests that seaweed is an iodine hyperaccumulator.

A recent paper reports the levels of long-lived radioisotopes in the trinitite.

The trinitite was formed from feldspar and quartz which were melted by the heat.

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