GEOL 001 Lecture Notes - Lecture 2: Continental Crust, Oceanic Crust, Nebular Hypothesis
19 Dec 2020
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Document Summary
Earth and other planets formed at essentially the same time. Solar system evolved from an enormous rotating cloud called the solar nebula. Nebula began to contract about 5 billion years ago. Assumes a flat, disk shape with the protosun (pre sun) at the center. Inner planted begin to form from metallic and rocky substances. Larger outer planets began forming form fragments of ices (h2o, co2, and others) Molten rock rose to produce a primitive crust. Chemical segregation established the three basic divisions of earth"s. A primitive atmosphere evolved from gases in earth"s interior interior. Less dense continental crust floats on denser mantle. Continental crust is less dense than oceanic crust. Oceanic crust has a higher density (heavier) than continental crust. Also called a craton: composed of shields and stable platforms. Composed of igneous rock that has been fractured and uplifted. Cooling and solidification or magma (molten rock) Sediments are derived from weathering of preexisting rocks.
