GEO 110 Lecture Notes - Lecture 13: Silicate Minerals, Oceanic Crust, Radiometric Dating
4 Feb 2020
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Document Summary
4. 5 billion years since the earth formed divided into eons, eras, and periods. Precambrian time: life has early beginnings but absent for geological record. Cambrian period: life on earth became abundant. Cenozoic era: most recent and nearly all landscape features visible today. Radiometric dating is the technique geologists use to determine the age of rocks. Volcanic and tectonic activity that brings fresh rocks to earth"s surface. Forces such as weathering by wind and water that work the earth"s surface. The planet has central core with several layers, or shells, surrounding it. The densest matter is at the center, and each layer above it is increasingly less dense. Crust, mantle, liquid outer core, solid inner core. Lithosphere is the solid, brittle outermost layer of the earth. Includes the crust and the cooler, brittle upper part of the mantle. Earth materials and they cycle of rock change. Asthenosphere lies below the lithosphere, is plastic (moldable)
