GEOL 1003 Chapter : Ch12 Proterozoic Eon
Document Summary
Australia has remarkably preserved fossils of the earliest animals lacking skeletons (ediacaran fauna) Introduction (cid:149) proterozoic eon is divided into 3 eras based on fossil records (cid:149) neoproterozoic (cid:149) mesoproterozoic (cid:149) Paleo & meso - litho (cid:149) cratons grew in size during. Younger rocks become welded onto borders of preexisting old rocks: sediment accretion shelf sediments compressed and metamorphosed, thickens and hardens the crust, accretion through orogeny. Paleo & meso - litho (cid:149) wopmay orogen oldest well-displayed remains of a mountain system (thoroughly modern in character) formed 2ga ago. Orogen any body of rocks deformed by an orogeny. Succeeded by flysch (cid:149) marine (such as shale) Paleo & meso - bio (cid:149) cyanobacteria flourished in the oceans (cid:149) Stromatolites more abundant than in archean (cid:149) habitat: shallow-marine & continental shelves, so their proliferation resulted in part from an increase in the size of continents, also from lack of grazers. (cid:149) reached greatest diversity ~ 1. 2 ga.
