EARTH121 Lecture Notes - Lecture 7: Quantitative Research, Absolute Dating, Facies

• School: University of Waterloo
• Department: Earth Sciences
• Course: EARTH121
• Professor: John Johnston

Document Summary

Lecture 7: grade, increasing crystal size, foliation coarseness, cleavage schistosity banding. Vertical facies contacts: conformable and unconformable sequences, unconformity. Nature of underlying rocks determines which kind of unconformity is present. Angular: parallel strata of sedimentary rock are deposited on tilted and eroded layers of sedimentary rock. Disconformity: between parallel layers of sedimentary rocks. Nonconformity: when sedimentary rocks lie above eroded metamorphic or igneous rocks. Look at underlying and rocks above and the relationship between them. Unconformities do not represent the same amount of missing time at all locations. Variations in deposition/erosion cause different types of unconformities. The geologic column: a composite stratigraphic column can be constructed, assembled from incomplete sections across the globe. Dating of rocks in different sections across earth are used to complete gaps. Age determination: relative ages: based upon order of formation. Principle of superposition: in an undisturbed succession of sedimentary rock layers, the youngest layer is at the top.