Electron flux is a key determinant of uranium isotope fractionation during bacterial reduction

AR Brown, M Molinas, Y Roebbert, A Sato… - … Earth & Environment, 2023 - nature.com
Uranium isotopic signatures in the rock record are utilized as a proxy for past redox
conditions on Earth. However, these signatures display significant variability that …

Cambrian radiation speciation events driven by sea level and redoxcline changes on the Siberian Craton

AY Zhuravlev, RA Wood, FT Bowyer - Science Advances, 2023 - science.org
The evolutionary processes of speciation during the Cambrian radiation and their potential
extrinsic drivers, such as episodic oceanic oxygenation events, remain unconfirmed. High …

Uranium and molybdenum isotope evidence for globally extensive marine euxinia on continental margins and in epicontinental seas during the Devonian …

S Yang, X Lu, X Chen, W Zheng, JD Owens… - … et Cosmochimica Acta, 2023 - Elsevier
Abstract The end-Devonian Hangenberg Crisis was one of the biggest Phanerozoic mass
extinctions. However, the mechanism (s) that triggered this event is still debated. In this …

Precipitation of CaCO3 in natural and man-made aquatic environments-Mechanisms, analogues, and proxies

M Dietzel, R Boch - Geochemistry, 2024 - Elsevier
Calcium carbonate precipitates occur in diverse and widespread aquatic environments, both
from marine to terrestrial natural surroundings and from anthropogenic to engineered …

Inverse Mo versus U isotope correlation of Early Cambrian highly metalliferous black shales in South China indicates synsedimentary metal enrichment from a near …

L Xu, B Lehmann, S Weyer, H Wen, J Mao… - Mineralium …, 2024 - Springer
The basal unit of the Early Cambrian black shale sequence of South China hosts sulfide-rich
polymetallic units, non-sulfidic vanadium-rich black shales, sapropelic alginite (combustible …

[HTML][HTML] Persistent late Tonian shallow marine anoxia and euxinia

J Stacey, A vS Hood, MW Wallace - Precambrian Research, 2023 - Elsevier
The increase in the complexity of eukaryotic life during the Tonian Period (ca. 1000 to 720
Ma) is commonly associated with the oxygenation of the Earth's ocean–atmosphere system …

[HTML][HTML] Regional conditions cause contrasting behaviour in U-isotope fractionation in black shales: Constraints for global ocean palaeo-redox reconstructions

SK Gangl, CH Stirling, HC Jenkyns, WJ Preston… - Chemical …, 2023 - Elsevier
The U-isotope system is a well-established palaeo-redox proxy that potentially constrains
the global extent of marine anoxia during average as well as extreme redox events …

[HTML][HTML] Source versus weathering processes as controls on the Mackenzie river uranium isotope signature

Q Charbonnier, MO Clarkson, RG Hilton, D Vance - Chemical Geology, 2023 - Elsevier
Uranium (U) isotope signatures (δ 238 U) recorded in sedimentary archives provide insight
into the paleo redox state of the ocean. But the robust interpretation of these sedimentary U …

Comparing thallium isotopes to paleosalinity and Mo-U isotope paleoredox proxies: A case study of the Upper Devonian Kettle Point Formation, Ontario

NC Bell - 2023 - uwspace.uwaterloo.ca
Black shale formations are utilised to reconstruct ancient global ocean redox conditions by
analyzing and inferring their geochemical and isotopic compositions. However, the accuracy …