EAE1011 Lecture Notes - Lecture 26: Proterozoic, Stromatolite, Precambrian
10 Aug 2018
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Fossils now at surface -> lost -not collected or is actively destroyed. Fossil assemblage -> lost to s(cid:272)ie(cid:374)(cid:272)e i(cid:374) private (cid:272)olle(cid:272)tio(cid:374)s, or kids" (cid:271)edroo(cid:373)s. What is life: replicating molecule, respires, organic (carbon based, e(cid:374)ergy tra(cid:374)sfer (cid:373)e(cid:272)ha(cid:374)is(cid:373) . What we (cid:862)know(cid:863: evidence of life and sedimentary rocks from 3. 8by, actual life found as fossils from ~3. 6by life started in the pre-cambrian, precambrian, = hadean(4. 6by -3. 8by, archaean(3. 8by-2. 5by, proterozoic(2. 5by -542my) Chemosynthesis: hydrothermal vent systems, bacteria use free electrons from sulphur to power their metabolism, oxidize hydrogen sulphide, add carbon dioxide and oxygen, and produce sugar, sulphur, and water, 6co (cid:1006)+ (cid:1006)4h(cid:1006) + 6o(cid:1006) c6h(cid:1005)(cid:1006)o6+ (cid:1006)4 + (cid:1005)8h(cid:1006)o. Early life: pre-cambrian was originally thought to be lifeless, since 1834, fossils have been found in archaean, the cambrian:pre-cboundary does show an explosion of life in the fossil record. Found in stromatolites in cherts (si), and dolomites (c: evidence in wa of hot spring deposits with cell-like structures and biominerals, accepted archaean microfossils are:
