ABOUT SIMPROP PROJECT. WHAT IS GEOCHRONOLOGY?
One of the
steps that will be studied in this thesis are the temporal relationships
between volcanic and plutonic rocks, but how do you do that? Well, since ancient
times humans have felt the passing of time as something bad in our short lives,
but geology has millions of years behind it and that doesn't worry it.
There is
a branch of geology that is focused to knowing how many years one rocks have
been on the Earth. This discipline is called Geochronology, or the art
(science) of dating the earth. Explaining how you get ages from things that have
lived millions of years is not easy. In general terms, the radioactive isotopes
of the chemical elements are responsible for these results.
Radioactive
isotopes, are elements that are not “emotionally stable” in its original form
and they may change to another -much more stable- during its life on earth.
This change, from one position to another, can be measured and as scientists we
can establish age ranges.
For example,
Uranium 238 (this is how isotopes are recorded) takes 4. 5 Billion years to
move to a more stable stadium called Thorium 324 and an average of 371.000
years to its more stable version: Lead 206. As you have seen there are tons of years
involved, but because of that great faculty of Uranium and its long isotopic
life, it is possible for us to date rocks that fall within that age range. . .
remember that the earth has 4500 Ma.
This is the
context for part of the SIMPROP project. We will date zircon minerals which are
preserved during millions of years in our granite and volcanic rocks. There are
more than 150 samples that will be dated with a machine called LA-ICP-MS and
the U/Pb. We hope to get ages of 300 Ma or so (We’ll see….).
You can
find this post (and others) in Spanish on my website.
by: S. Schamuells
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