Earth Sciences 1022A/B Lecture Notes - Lecture 1: Micrite, Banded Iron Formation, Richter Magnitude Scale

• School: Western University
• Department: Earth Sciences
• Course: Earth Sciences 1022A/B
• Professor: Stephen R Hicock

Document Summary

Uniformitariaism: the present is the key to the past . Our earth is 4. 6 billion years old. Nebular hypothesis- 5 billion years ago. Nebula (cloud) of hydrogen and helium contracted under gravity into the flat disc of our solar system. Earth formed core, mantle, crust crust core mantle. Crust and uppermost mantle formed rigid plates of . Lithosphere that ride on the . Asthenosphere whish moves by convection. Most geologic activity (e. g. earthquakes, volcanoes, landslides) happens at plate. Earth system & rock cycle. Earth is a system of interacting hydrosphere, atmosphere, biosphere, and geosphere. Material is recycled in the rock cycle. A mineral is a solid chemical compound that is found in nature- only mother nature can make a mineral. There are approximately 4,000 minerals discovered to this date- only about 20 are really common in the earth"s crust. Silicon- oxygen tetrahedron (4, pyramid) (sio4) 4- . Olivine: single tetrahedra bonded to fe+2, mg+2 ions (no cleavage)