The Archean‐Proterozoic Boundary and the Great Oxidation Event

Abstract

INDEX Acidithiobacillus, 132 Amazon Craton biostratigraphy of, 102-4, 103f, 105f cap carbonate in southern, 98 contact between glacial deposits and cap carbonate in, 94, 97f Cryogenian-Ediacaran boundary in southern, 89-108, 90f, 92f, 95f-97f, 98f, 100f, 103f, 105f, 106f geological-structural setting of southern, 95f geologic map of southwestern, 90f global correlations with, 104-7, 105f, 106f insertion of post-Marinoan carbonates of, 106f lithostratigraphy and major geologic events of, 92f Marinoan cap carbonate in southern cap carbonate, 98-102, 98f, 100f cap dolostone, 99-101, 100f cap limestone cementstone, 101-2 Marinoan glacial deposits, 93-94, 95f, 96f paleobiology of, 102-4, 103f, 105f paleogeographic map for, 74f representative fossils of, 103f simplified stratigraphic section of glacial deposits with, 96f Ammonoids, 166 Angara Craton, 74f Anomaly, 29 Anticosti Island, 147f Apennines, 186f Araras Group acritarch specimens in, 104 carbon isotope chemostratigraphy for, 105f insertion of post-Marinoan carbonates of, 106f lithostratigraphy of, 105f microbial laminites in, 103 Aravalli-Bundelkhand Craton, 54-55, 54f, 59-60 Archean-Proterozoic boundary banded iron formation in, 35 BIF with, 42f chromium isotopes in, 39-40, 39f global change from, 35 Great Oxidation Event with, 9, 35-43, 36f, 38f, 39f, 41f, 42f molybdenum isotopes in, 40-41, 41f placement of, 42-43, 42f present atmospheric level exceeded by, 35, 37, 40-43 sulfur isotopes in, 36-38, 38f Arequipa Massif, 74f Argana Basin, 186f Argillaceous red, nodular, bioturbated wackestone, 166, 167f, 171f Aspidella, 131f Astartekløft, 192 Asteroid impact event, 224-25 Atar Group carbon isotope chemostratigraphy of, 80f Calcario Tangará quarry, 98f Calcium isotopes, 9-10 Calymmian period, 48, 51f, 52-53, 59, 64 depositional age for Dongchuan Group, 56 deposition of large red beds during, 61 sedimentary rocks of, 63 Calymmian rift, 47 Cambrian explosion, 123-24 CAMP. See Central Atlantic magmatic province Canada Ordovician paleogeographic position in, 147f Truro Island, Arctic in, 147f, 150-51, 152f Carbonate-associated sulfate (CAS) analyses in transitional Ediacaran to Cambrian successions, 123 composition of, 60 isotopic compositions of, 121-22 measurements of sulfur isotopes on, 8 Carbonate microfacies argillaceous red, nodular, bioturbated wackestone, 166, 167f, 171f gray/yellow nodular sponge wackestone, 166, 168f, 171f laminated bindstone, 166, 169f, 171f, 172f oncoid wackestone/floatstone, 166, 168, 170f, 172f Carbon isotopes, 5-6. See also Jurassic-Cretaceous carbon isotope geochemistry analysis and sampling strategies with, 165-66 Araras Group in chemostratigraphy with, 105f carbonate sequences data for, 58f, 59, 59f, 60 chemostratigraphy, 75f, 76f, 79f, 80f, 81f, 105f, 193, 194f-95f composition analysis results with, 172-74, 173f, 173t compositions in Mesoproterozoic-Neoproterozoic transition of, 81, 82f curves coupled with δ 53 Cr, 10, 12 Ediacaran-Cambrian transition, trends leading up to, 122 Permian-Triassic boundary with composition of, 160-62, ...

Unconformities and Gold in New Zealand: Potential Analogues for the Archean Witwatersrand of South Africa

“…Two younger units, the Ventersdorp Contact Reef of ~2780 Ma and the Black Reef of ~2640 Ma, also contain significant gold. All these units precede the end of the global gold event of 2700 to 2600 Ma (Figure 2a) [37], the suggested global oxidation event at approximately 2450 to 2300 Ma [41], and the defined Archean-Proterozoic boundary of 2500 Ma. The significance of these ages is that several of the Archean basins, including the Witwatersrand, were already in place before the major global gold event.…”

The supercontinent cycle and Earth's long‐term climate

“…The Huronian glaciations accompanying Kenorland/Lauroscandia also coincide with the Great Oxidation Event (c. 2.43–2.25 Ga 178 ), during which biologically produced O 2 first started to accumulate in the atmosphere, 179 perhaps as a result of the breakup‐related evolution of the first oxygen‐requiring cyanobacteria, 180 or a LIP‐generated pulse of sulphate to the oceans, the reduction of which liberated oxygen. 181 The rise in atmospheric oxygen, evident in the loss of Fe‐poor paleosols, detrital pyrite, and detrital uraninite, 182 , 183 , 184 in the first appearance of redbeds, 185 and in the loss of mass‐independent fractionation of sulfur isotopes in sedimentary rocks, 186 , 187 likely led to the demise of atmospheric methane, the most powerful of the greenhouse gases, thereby providing an alternative mechanism for dramatic climatic cooling. 188 , 189 , 190 …”