Biological (Methods for Determining Age)

Biostratigraphy (fossil record):

The approach to stratigraphy that utilizes the distribution of fossils in the stratigraphic record and the organization of strata into units of the basis of their contained fossils

Racemization:

A method of geochronology based on the chemical racemization of amino acids; used to determine the elapsed time since an organism has died

Lichonometry

Measurement of the diameter of lichens growing on exposed rock surfaces as a method of dating geomorphic features

Growth Ring:

a. tree ring:

Layer of wood produced in a tree or woody plant during its annual growth period seen in cross section as a ring and analyzed for chronologic and climatic data based on the number and relative sizes of the rings

b.

Growth rings in corals used to date a reef