He was employed at Caltech's Division of Geological & Planetary Sciences at the time of writing the first edition.
He is presently employed in the Space & Atmospheric Sciences Group at the Los Alamos National Laboratory.
by Tas Walker A geologist works out the relative age of a rock by carefully studying where the rock is found in the field.
In a separate article (Radiometric dating), we sketched in some technical detail how these dates are calculated using radiometric dating techniques. Its crust is continually being created, modified, and destroyed.As a result, rocks that record its earliest history have not been found and probably no longer exist.It has become increasingly clear that these radiometric dating techniques agree with each other and as a whole, present a coherent picture in which the Earth was created a very long time ago.Further evidence comes from the complete agreement between radiometric dates and other dating methods such as counting tree rings or glacier ice core layers. Wiens has a Ph D in Physics, with a minor in Geology.