GSC 111 Lecture Notes - Lecture 12: Laurentia, Grenville Orogeny, Orogeny
26 Nov 2017
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Document Summary
Paleogeography and configurations may never be known. Archean metamorphosed volcanic and sedimentary rocks associated with protocontinent. Larger cratons at the end of the archean. Accumulation of sediments along continental margin (subduction zone) 2 billion year old modern mountain building. High heat, high pressure,= metamorphic belt (zone of collision) Fold and thrust belt (thrust fault)0- move away. Transport east to west: weathering of mountain metamorphic belt. Molasse- fills up basin- stuff deposited on it. Keweenawan failed rft (1. 2-1 bya)= basaltic dikes and flows, ceased rifting. Grenville orogeny (1. 1 bya)- mountain building on east coast, stopped rifting. Proterozoi(cid:272): repeated (cid:272)ollisio(cid:374) a(cid:374)d asse(cid:373)(cid:271)ly a(cid:374)d (cid:271)reaki(cid:374)g apart of earth"s growi(cid:374)g (cid:272)o(cid:374)ti(cid:374)e(cid:374)ts. 550 mya- pan african and contemporaneous orogenic belts. 1 bya- grenville and contemporaneous orogenic belts. Aerobic respiration utilizes oxygen- must bury plants/carbon. Remove other inorganic chemicals that will utilize oxygen rust = fe2+ + o2 fe3+ (iron sinks in ocean use up oxygen) Oxygen produced and absorbed by seabed rock and ocean.
