ERSC 2P03 Final: Exam review- ERSC 2P03

• School: Brock University
• Department: Earth Sciences
• Course: ERSC 2P03
• Professor: Martin J. Head

Document Summary

Formation of large continental plates, most of earth"s crust formed. First oxygen-dependent organisms evolved including first eukaryotes and indeed first metazoans. Tectonic activity slowed down (vast exposures of proterozoic rocks essentially metamorphosed. Ca(cid:373)pbell"s o(cid:374)io(cid:374) soup does make peter pale (cambrian), (ordovician)(silurian)(devonian)(mississippian)(pennsylvanian) (permian) Tillites plus glacially polished and striated bedrock provides evidence of widespread glaciations at several times during proterozoic, and a tillite in ontario"s bruce formation is 2. 7 ga (late archean) Banded iron formations: likely source of iron and silica was volcanism on sea floor. Iron is highly reactive, in an oxidizing environment it forms iron hydroxides that are insoluble in water, and precipitate. So bifs are evidence of early o2 in atmosphere, but oscillating mechanism to provide alternations of red and grey banding is not known. Great oxygenation event- oxygen levels rose to 3 % of todays levels. (2. 4-1. 8 ga) Ba(cid:374)ded iro(cid:374) for(cid:373)atio(cid:374)s did(cid:374)"t for(cid:373) after (cid:1005). 8 ga, o(cid:454)(cid:455)ge(cid:374) le(cid:448)els (cid:449)ere to high.