GEOLOGY 105 Chapter 12: GEOLOGY 105 Chapter 11-12: GEOLOGY 105 Chapter 11-1: GEOLOGY 105 Chapter 11-: GEOLOGY 105 Lecture : geology

• School: UMASS-Amherst
• Department: Geology
• Course: GEOLOGY 105
• Professor: Stephen Burns

Document Summary

Numerical age= age of a feature given in years. Relative age= the age of one feature with respect to another in a sequence: describe the principles that allows us to determine relative age of geologic events. Species originate within geologically brief time frames, few species persist for more than a few million years, and extinction is permanent. Fossils that are, for example, uniquely found within maastrichtian rocks can be used to illustrate temporal equivalence of isolated strata that bear these same fossil assemblages. Thus, physically isolated sedimentary sequences can be temporally correlated in the absence of datable igneous intrusions. Describe the differences between the 3 kinds of unconformities An unconformity occurs when sedimentary layers are deposited on top of a surface of erosion or nondeposition. Three kinds of unconformities are recognized: unconformities, disconformities, and angular unconformities. Nonconformities arise when sedimentary strata are deposited on top of crystalline (metamorphic or igneous) rock.