Ar (argon), the atom typically remains trapped within the lattice because it is larger than the spaces between the other atoms in a mineral crystal.
But it can escape into the surrounding region when the right conditions are met, such as change in pressure and/or temperature.
When an organism dies, if the conditions are right, it becomes covered in sediments, which, after being subjected to pressure, becomes rock.
This takes a very long time, and the actual organism decomposes by then.
A soft organism like a worm or jellyfish usually does not get fossilized because it decomposes too fast.
Only the hard parts like skeletons and teeth remain long enough to keep the imprint in the rock while the rock is forming.
Fossils is an identification event which rotates with Rocks and Minerals every two years.
It is based on measurement of the product of the radioactive decay of an isotope of potassium (K) into argon (Ar).In 1859, the German-American Jacob Kuechler (1823–1893) used crossdating to examine oaks (Quercus stellata) in order to study the record of climate in western Texas.During the first half of the 20th century, the astronomer A. Douglass founded the Laboratory of Tree-Ring Research at the University of Arizona.It is also used in radiocarbon dating to calibrate radiocarbon ages.New growth in trees occurs in a layer of cells near the bark.