1. The Eras of Geologic Time
... relationships (most commonly, vertical/stratigraphic position). These subdivisions are given names, most of which can be recognized globally, usually on the basis of fossils. • Absolute time ("chronometric") -- numerical ages in "millions of years" or some other measurement. These are most commonly obtained by using radiometric dating methods performed on appropriate rock types. Some of the most important discoveries of ... of geologic time from sixty five to two hundred and twenty five million years ago and is put into three geologic time periods: Triassic, Jurassic, and Cretaceous. T...
- Word Count: 1841
- Approx Pages: 7
- Grade Level: Undergraduate