GEOL 101 Study Guide - Quiz Guide: Unconformity, Stratigraphic Column, Closure Temperature
Document Summary
Once a species becomes extinct, it never reappears higher in the sequence: strata are not necessarily deposited continuously at a location. An interval of nondeposition and/or erosion produces an unconformity. Geologists recognize three kinds: angular unconformity, nonconformity, and disconformity: a stratigraphic column shows the succession of strata in a region. A given succession of strata that can be traced over a fairly broad region is called a stratigraphic formation: the process of determining the relationship between strata at one location and strata at another is called correlation. A geologic map shows the distribution of formations, as well as of geologic structures: a composite chart that represents the entirety of geologic time is called the geologic column. Eons are subdivided into eras, eras into periods, and periods into epochs: the numerical age of rocks can be determined by isotopic (radiometric) dating.
