discussion-review - Geology types of rocks o igneous- from...

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Geology - types of rocks o igneous- from volcanoes (Mafic, Felsic) o metamorphic- sedimentary rocks cooked by pressure and heat over time o sedimentary- built up over time (Clastic, fossils) - Isostacy - the continental shelves “float” on mantle at an elevation depending on their thickness and weight - S-wave : across earth, P-wave : through earth o Lack of s-waves and p-wave refraction evidence of liquid core of earth - Convection creates rifts (such as the Atlantic Ocean) with hydrothermal vents o Thus, sea floor near rift younger than sea floor away from rift - Magnetic polarity can be measured to understand rate of spreading in continental drift - Plumes and the mantle generate convection o Plume tails can create volcanic islands over time - From eon to period - Sedimentation (Powell) o Accommodation space – space available for sediment to accumulate vertically o Base levels (global base level = sea level) – lowest point water (or sediment) can go o Biases of the fossil record o Relative sea level change- Eustatic (global) sea level + plate tectonics o Transgression – sea level rises o Regression (progredation) filling accommodation space o Fair weather wave base o Storm wave base - How are fossils formed? o Taphonomy – study of decay o Bioturbation - caused by burrowing organisms (trace fossil) o Fossils often deformed by pressure - Hadean and Archean (first two eons of Precambrian) 2500-4600 mya o Earliest continental crust did not form until after bombardment 4bya o Mostly N in atmosphere, no O until photosynthetic organisms
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This note was uploaded on 03/19/2008 for the course EEB 120 taught by Professor Jacobs during the Spring '08 term at UCLA.

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discussion-review - Geology types of rocks o igneous- from...

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