GEO 1111 Lecture Notes - Lecture 6: Geologic Time Scale, Radiometric Dating, James Ussher

• School: University of Ottawa
• Department: Geology
• Course: GEO 1111
• Professor: Robert Jack Cornett

Document Summary

The begat statements (said earth is about 6000 yrs old) Jack hills; metaconglomerate (aus), zircons in this rock are over 4 billion yrs. Relative dating + absolute dating = geological time scale. Rockies consist of sedimentary rocks, forces of compression at plate boundary have tilted these strata. Study of large scale patterns in rocks. Principle of superposition: higher rock unit is younger than lower. Fossils used to define geological periods are called index fossils (ex: ammonites), preferably lived for short amount of time in large area. Conformable contacts: the contacts between two rocks is conformable is there is not significant break. Unconformity is due to erosion or non-deposition. Types on unconformity: angular : sedimentary rocks are eroded and tilted, new sedimentary rocks are laid on top, disconformity : sedimentary rocks are eroded, then more are laid on top (same as angular, without tilting)