GSC 110 Lecture Notes - Lecture 9: James Hutton, Erosion Surface, Absolute Dating
2 Jan 2020
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Document Summary
Lecture 9: geologic time & the rock record. Introduction: the concept that most geologic processes happen very slowly was proposed by james. Reading the record of layered rocks: layered sedimentary or volcanic rocks contain important clues about past environments at. & near earth"s surface: cold, hot, vegetation, animals, rocks on top are younger, on bottom older, their sequence & relative ages provide the basis for reconstructing much of earth"s history, the study of strata is called stratigraphy. It must be assumed that rate of sedimentation was constant throughout time of sediment accumulation. Rocks can be tilted, eroded, folded : so struggled with age of earth for a long time, erosion happens, need to look at & understand gaps in accumulation of sediment. If a distinctive index fossil is recognizable at an outcrop, a rapid & reliable means of correlation is available. Mammals first appeared during mesozoic era as did flowering plants: mammals dominated cenozoic era.
