112-pp18 - UNIVERSITY OF SOUTH ALABAMA Last time we...

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1 GY 112: Earth History Proterozoic Tectonics UNIVERSITY OF SOUTH ALABAMA Last time we covered… 1) The Early Atmosphere 2) The Oceans and Hydrosphere 3) The Change Ozone UV radiation in the upper atmosphere makes ozone 2H 2 O + UV H 2 + O 2 2O 2 + UV O 3 + O Oxygen Cyanobacteria (e.g., the microorganisms comprising stromatolites) and photosynthesis made oxygen starting at least 3.865 GA ago. . 6CO 2 + 6H 2 O C 6 H 12 O 6 (“sugar”) + 6O 2 Photosynthesis Oxygen The atmosphere became oxidizing by 1.8 GA and reached near current levels by the Ordovician. ht p:/ www.biologie.uni-hamburg.de/b-online/ge42/01.jpg Today’s Agenda (long!) Proterozoic Tectonics 1) The Proterozoic time frame 2) Paleogeography 3) Tectonics 1 (Wopmay Orogeny) 4) Other “orogenies” 5) Diamonds (web notes only) (Web Lectures 18, 19)
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2 The Proterozoic Eon 4.6 GA to 4.1 GA Hadean 4.1 GA to 2.5 GA Archean 2.5 GA to 550 MA Proterozoic 550 MA to 0 MA Phanerozoic Time Eon Platform : younger (550 MA-2.5 GA) sedimentary rocks ht p:/ mmsd1.mms.nrcan.gc.ca/efab/images/slide1canMap_e.gif The Proterozoic Eon 4.6 GA to 4.1 GA Hadean 4.1 GA to 2.5 GA Archean 2.5 GA to 550 MA Proterozoic 550 MA to 0 MA Phanerozoic Time Eon 2.5 GA to 1.6 GA Paleoproterozoic 1.6 GA to 900 MA Mesoproterozoic 900 MA to 550 MA Neoproterozoic Age Division (ERA) • Paleo- old • Meso-middle • Neo-new • This is about as far back as we can go with detailed paleogeography Proterozoic Paleogeograpy
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112-pp18 - UNIVERSITY OF SOUTH ALABAMA Last time we...

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