Cosmogenic dating methods
One of them can take drilled rock dust, heat it up until it melts and the smell the molecules that emanate from the melting crystals.
What we learned this week is that some of the molecules that this instrument can measure are the kind that can be used to calculate radiometric ages.
Similarly layers of rock on Mars can be tested and rocks in one area to find out if they might have been exposed longer than in other areas. (1994) A form of this analysis can be done for rocks on Earth as well.
It is called cosmogenic nuclide dating and it allows for rough estimates of the rates of erosion, or exposure times, in different locations (eg.
how fast are rocks eroding in Utah vs deserts in other places in the world).
So what can we learn about erosion on the surface of Mars from this form of analysis?
The 1 meter per million years is a very rough estimate so maybe it is only ½ meter or 2 meters per million years.
The Sheepbed mudstone was drilled and chemically analyzed.
There results of that analysis and others provide strong evidence that this area was a lake.
The precision of this instrument is not like we have in labs here on Earth but nonetheless it’s an impressive achievement and gives us our first direct test of age of rocks and allows to even infer rates of erosion of rocks.
On sol 279 (May 18, 2013), Curiosity drilled this hole at a second site named Cumberland.