Rhenium isotopes reveal enhanced rock organic carbon oxidation over the Toarcian Oceanic Anoxic Event.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41991920.
- Also identified by DOI 10.1038/s41467-026-71533-6.
- No licence information is recorded for this record.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
Weathering plays a central role in the geological carbon cycle. Silicate mineral weathering is invoked as a stabilizing feedback on CO<sub>2</sub> emissions, for example from volcanism during the emplacement of Large Igneous Provinces. However, modern-day studies show weathering can emit CO<sub>2</sub> during oxidation of rock organic carbon (OC<sub>petro</sub>) in sedimentary rocks and function as a positive feedback on climate warming. Here we measure the rhenium isotope composition (δ<sup>187</sup>Re) of Early Jurassic marine sediments to explore how OC<sub>petro</sub> oxidation rates changed during warming across the Toarcian Ocean Anoxic Event (T-OAE). We find a 0.22 ± 0.10‰ decrease in δ<sup>187</sup>Re values during the T-OAE, with mass balance modeling showing this can be explained by increased OC<sub>petro</sub> weathering intensity on land associated with 6-7 °C of global warming. We estimate this could have delivered 7600-20,490 PgC to the oceans and atmosphere, demonstrating that chemical weathering does not simply act as a stabilizing feedback during hyperthermal events.