Wei, G-Y;
Wei, W;
Wang, D;
Li, T;
Yang, X;
Shields, GA;
Zhang, F;
... Ling, H-F; + view all
(2020)
Enhanced chemical weathering triggered an expansion of euxinic seawater in the aftermath of the Sturtian glaciation.
Earth and Planetary Science Letters
, 539
, Article 116244. 10.1016/j.epsl.2020.116244.
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Abstract
The Cryogenian Period comprised two episodes of global glaciation (Sturtian and Marinoan glaciations) separated by a non-glacial interval, which was characterized by early radiations of eukaryotic algae and putative metazoans. Geochemical data indicate that the non-glacial interval might be marked by a transient marine oxygenation, nevertheless oceanic redox conditions varied both in time and space. Further, the links between non-glacial climate and marine redox variations are not well constrained. Here we present high-resolution lithium isotope (Li), Fe speciation and trace element (Mo and U) data for clastic sedimentary rocks from the Cryogenian interglacial Datangpo Formation, South China, in order to track the evolution of continental chemical silicate weathering and driving factors behind marine redox variability during the Cryogenian non-glacial interval. A significantly negative Li excursion of ‰ is observed in the basal Datangpo Formation, suggesting a dramatic increase in chemical silicate weathering intensity in the aftermath of the Sturtian glaciation. Expansion and contraction of anoxic-sulfidic conditions, as demonstrated by Fe speciation and trace element (Mo and U) data, mirror changes in silicate weathering intensity. Our study provides evidence that greater nutrient and sulfate availability, due to high silicate weathering intensity associated with increased exposure of fresh rocks and a warm climate, facilitated the spread of euxinic waters over the continental margins of the otherwise ferruginous Cryogenian ocean.
| Type: | Article |
|---|---|
| Title: | Enhanced chemical weathering triggered an expansion of euxinic seawater in the aftermath of the Sturtian glaciation |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.epsl.2020.116244 |
| Publisher version: | https://doi.org/10.1016/j.epsl.2020.116244 |
| 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: | Cryogenian ocean; lithium isotopes; silicate weathering; marine redox states; South China |
| 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/10109802 |
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