| Title | Evaporite deposition in the mid-Neoproterozoic as a driver for changes in seawater chemistry and the biogeochemical cycle of sulfur |
| |
| Author | Prince, J K G; Rainbird, R H ; Wing, B A |
| Source | Geology 2019 p. 1-5, https://doi.org/10.1130/G45464.1 |
| Image |  |
| Year | 2019 |
| Alt Series | Natural Resources Canada, Contribution Series 20180383 |
| Publisher | Geological Society of America |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf (Adobe® Reader®) |
| Province | Northwest Territories |
| NTS | 78B/04; 78B/05; 87G/01; 87G/02; 87G/07; 87G/08; 87G/09; 87G/10; 87G/15; 87G/16; 87H; 88A/01; 88A/02; 88A/07; 88A/08 |
| Area | Victoria Island; Minto Inlet; Wynniatt Bay |
| Lat/Long WENS | -117.1667 -111.1667 72.5000 71.0000 |
| Subjects | sedimentology; geochemistry; bedrock geology; lithology; sedimentary rocks; evaporites; gypsum; anhydrite; calcite; dolomites; limestones; shales; mudstones; grainstones; siltstones; claystones;
arenites; sulphates; depositional history; depositional environment; paleoenvironment; sea water geochemistry; sulphur geochemistry; isotopic studies; atmospheric geochemistry; oxygen geochemistry; biogeochemistry; modelling; basins; tectonic
setting; paleoclimates; Neoproterozoic; Tonian; Minto Inlet Formation; Shaler Supergroup; Rodinia; Precambrian; Proterozoic |
| Illustrations | time series; bar graphs; location maps; geoscientific sketch maps; lithologic sections; geochemical profiles; graphs |
| Program | GEM: Geo-mapping for Energy and Minerals PGE/Base Metals - Victoria Island (NWT and Nunavut) |
| Released | 2019 02 26 |
| Abstract | We utilized a novel approach to modeling the oceanic sulfur cycle by combining delta-34S and delta-33S curves from sulfate evaporite minerals in order to investigate redox conditions during the
mid-Neoproterozoic. This technique allowed us to estimate the oxidized and reduced proportions of the total oceanic sulfur sink. Isotopic data from the mid-Neoproterozoic Minto Inlet Formation (Victoria Island, Northwest Territories, Canada; ca. 850
Ma) show a limited range (16.8 per mille ± 1.4 per mille) in delta-34S of seawater sulfate and a sulfur cycle that is strongly shifted toward the sulfate sink (pyrite burial fraction, fp, = 0.2), suggesting oxidizing conditions in the ocean and
atmosphere at the time of deposition. These evaporites and others, which were deposited contemporaneously within a huge intracontinental basin, acted as a chemical pump, removing sulfate from the oceans and oxygen from the atmosphere to be buried as
sulfate evaporites. |
| Summary | (Plain Language Summary, not published)
We analyzed sulphur isotopes from sulfate evaporite minerals from the Minto Inlet Formation (Shaler Supergroup)in order to investigate redox conditions
in the ocean approximately 850 million years ago. The isotopic data show a limited range in d34S of seawater sulfate and a sulfur cycle that is strongly shifted toward the sulfate sink, suggesting oxidizing conditions in the ocean and atmosphere at
the time of deposition. These evaporites and others, which were deposited contemporaneously within a huge intracontinental basin, acted as a chemical pump, removing sulfate from the oceans and oxygen from the atmosphere to be buried as sulfate
evaporites. |
| GEOSCAN ID | 313580 |
|
|