Tostevin, R;
He, T;
Turchyn, AV;
Wood, RA;
Penny, AM;
Bowyer, F;
Antler, G;
(2017)
Constraints on the late Ediacaran sulfur cycle from carbonate associated sulfate.
Precambrian Research
, 290
pp. 113-125.
10.1016/j.precamres.2017.01.004.
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Abstract
We report new sulfur isotope compositions (δ34S) in carbonate associated sulfate (CAS) and pyrite from the lower Nama Group, Namibia (∼550 to <547 Ma), and use these data to interrogate terminal Ediacaran sulfur cycle dynamics. Our extraction method utilizes an improved pre-leaching procedure that reduces the likelihood of contamination from matrix-bound sulfur. Data generated with the improved extraction method show CAS δ34S as much as 12‰ higher (34S-enriched) than previously reported which suggests a reevaluation of the phenomenon of ‘superheavy’ pyrite. The average δ34S of seawater sulfate increases from 30 to 38‰ in the lower Nama Group, and we correlate this rise in δ34S among contemporaneous marine basins. Global seawater sulfate δ34S >35‰ is highly unusual in Earth history, and in the terminal Ediacaran is best explained by a high pyrite burial flux. Pyrite in the Nama Group is close in isotopic composition to coeval sulfate, but the sulfur isotope fractionation between sulfate and pyrite varies widely among different studied basins, suggesting highly heterogeneous redox and depositional conditions.
| Type: | Article |
|---|---|
| Title: | Constraints on the late Ediacaran sulfur cycle from carbonate associated sulfate |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.precamres.2017.01.004 |
| Publisher version: | https://doi.org/10.1016/j.precamres.2017.01.004 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Science & Technology, Physical Sciences, Geosciences, Multidisciplinary, Geology, Sulfur isotopes, Neoproterozoic, Ediacaran, Superheavy pyrite, Method development, Carbonate-associated sulfate, PROTEROZOIC NAMA GROUP, LOW MARINE SULFATE, ISOTOPE FRACTIONATION, SEAWATER CHEMISTRY, GEOCHRONOLOGICAL CONSTRAINTS, NATURAL-POPULATIONS, CAMBRIAN SEAWATER, SECULAR VARIATION, HUQF SUPERGROUP, TRACE-ELEMENTS |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10074311 |
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