A process-based geochemical framework for carbonate sediments during marine diagenesis

MS Hashim, SE Kaczmarek, GW Naa, DL Bish… - … et Cosmochimica Acta, 2024 - Elsevier
A significant proportion of marine calcium carbonate sediments are comprised of metastable
minerals that are susceptible to diagenetic alterations during burial. These reactions can …

Effects of sodium and potassium concentrations on dolomite formation rate, stoichiometry and crystallographic characteristics

MS Hashim, KG Rose, HF Cohen… - …, 2023 - Wiley Online Library
This study uses high temperature (215° C) dolomitization experiments to explore the effects
of sodium (Na) and potassium (K), two common constituents of natural fluids, on dolomite …

Characterizing the marine iodine cycle and its relationship to ocean deoxygenation in an Earth system model

K Cheng, A Ridgwell, DS Hardisty - Biogeosciences, 2024 - bg.copernicus.org
Iodine (I) abundance in marine carbonates (measured as an elemental ratio with calcium,
I/Ca) is of broad interest as a proxy for local/regional ocean redox. This connection arises …

Iodine-to-calcium ratios in deep-sea scleractinian and bamboo corals

YJ Sun, LF Robinson, IJ Parkinson… - Frontiers in Marine …, 2023 - frontiersin.org
The distribution of dissolved iodine in seawater is sensitive to multiple biogeochemical
cycles, including those of nitrogen and oxygen. The iodine-to-calcium ratio (I/Ca) of marine …

[HTML][HTML] Refining the carbonate-associated iodine redox proxy with leaching experiments

K Zhang, G Tarbuck, GA Shields - Chemical Geology, 2024 - Elsevier
Iodate ions can substitute for carbonate in crystal lattices, which is why carbonate-
associated iodine (CAI) is increasingly being used to track redox-sensitive iodine species …

Dynamic redox conditions in Mesoproterozoic shallow seawater: Constraints from carbonate fabrics and geochemistry

L Sun, X Shi, X Zhou, L Zhou… - Geological …, 2025 - pubs.geoscienceworld.org
The delayed eukaryote evolution during the mid-Proterozoic may have been linked to
prolonged low oxygen levels during this period. Two short oxygenation events have recently …

Mineralogy-based stepwise dissolution of dolomitic limestone reveals high iodine content in water-column precipitated calcite and well‑oxygenated shallow seawater …

H Fang, D Tang, L Zhou, G Jiang, X Shi, L Liang… - Chemical …, 2024 - Elsevier
Abstract Carbonate I/(Ca+ Mg) has been used as a proxy to track shallow-seawater oxygen
levels through Earth's history. However, due to diagenetic alteration and homogenization of …

Calcium isotopes support spatial redox gradients on the Tethys European margin across the Triassic-Jurassic boundary

AN Prow-Fleischer, Z Lu, CL Blättler, T He, P Singh… - Chemical …, 2025 - Elsevier
The end-Triassic mass extinction was among the most severe biotic crises of the
Phanerozoic. It has been linked with the global expansion of marine anoxia, and the …

More than deoxygenation: Linking iodate reduction to nitrogen, iron, and sulfur chemistry in reducing regimes

N Evans, E Johnson, A Taing… - Journal of …, 2024 - Wiley Online Library
A striking feature of Oxygen Deficient Zones (ODZs) on the eastern boundary of the Pacific
Ocean are large subsurface plumes of iodide. Throughout the oceans, iodate is the …

A prominent oxygenation event in the late Mesoproterozoic broke the calm of the second half of the “Boring Billion”

L Meng, X Shi, L Zhou, J Li, W Liu, B **e, L Sun… - Palaeogeography …, 2025 - Elsevier
The redox conditions on Earth's surface during the so-called “Boring Billion”(ca. 1.8–0.8 Ga)
were characterized by an overall low-oxygen background punctuated by pulsed …