outline15 - continents? Archean rocks - tonalites (granitic...

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  Outline 15 3/20/03     Important factors for Earth favorable climate      1. distance from Sun      2. nearly constant solar output      3. large moon (vs. Earth)      4. liquid H2O (T , CO2 )      5. life (O2 )      6. large outer planets      7. plate tectonics  Q   crust      \ mantle     density stratified core       / growth of the crust  (curve)       \ growth of the oceans  (curve)       outgassing primitive reducing atmosphere /
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oxidizing atmosphere - growth of O2 in atmosphere (curve)      photodissociation - breakdown of H2O in upper atmosphere      photosynthesis - release of O2 by algae + plants   shields, basement rocks metamorphic rocks granitic intrusions concentric age banding in Precambrian shields - growth of 
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Unformatted text preview: continents? Archean rocks - tonalites (granitic gneisses) - early cont. crust - greenstones with komatiites (high Mg basalts) - early ocean crust Proterozoic rocks - tonalites + greenstones - anorthosites, granodiorites - greywackes - siliceous banded iron ores (chert + Fe2O3) Eocambrian (Vendian) glaciation - tillite (lithified till) "Snowball Earth" hypothesis - whole Earth froze in Latest Proterozoic? Rodinia breakup (L. Protero.), formation of Gondwana (Camb.) Back to Outline Main page...
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This note was uploaded on 05/05/2011 for the course GEO 404c taught by Professor Staff during the Spring '08 term at University of Texas at Austin.

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outline15 - continents? Archean rocks - tonalites (granitic...

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