Acceleration of dolomitization by zinc in saline waters

Vandeginste, Veerle; Snell, Oliver; Hall, Matthew R.; Steer, Elisabeth; Vandeginste, Arne

Abstract

Dolomite (CaMg(CO3)2) plays a key role in the global carbon cycle. Yet, the chemical mechanisms that catalyze its formation remain an enigma. Here, using batch reactor experiments, we demonstrate an unexpected acceleration of dolomite formation by zinc in saline fluids, reflecting a not uncommon spatial association of dolomite with Mississippi Valley-type ores. The acceleration correlates with dissolved zinc concentration, irrespective of the zinc source tested (ZnCl2 and ZnO). Moreover, the addition of dissolved zinc counteracts the inhibiting effect of dissolved sulfate on dolomite formation. Integration with previous studies enables us to develop an understanding of the dolomitization pathway. Our findings suggest that the fluids’ high ionic strength and zinc complexation facilitate magnesium ion dehydration, resulting in a dramatic decrease in induction time. This study establishes a previously unrecognized role of zinc in dolomite formation, and may help explain the changes in dolomite abundance through geological time.

Citation

Vandeginste, V., Snell, O., Hall, M. R., Steer, E., & Vandeginste, A. (2019). Acceleration of dolomitization by zinc in saline waters. Nature Communications, 10, https://doi.org/10.1038/s41467-019-09870-y

• Journal Article Type: Article
• Acceptance Date: Mar 11, 2019
• Online Publication Date: Apr 23, 2019
• Publication Date: Apr 23, 2019
• Deposit Date: Mar 28, 2019
• Publicly Available Date: Apr 24, 2019
• Journal: Nature Communications
• Electronic ISSN: 2041-1723
• Publisher: Nature Publishing Group
• Peer Reviewed: Peer Reviewed
• Volume: 10
• Article Number: 1851
• DOI: https://doi.org/10.1038/s41467-019-09870-y
• Public URL: https://nottingham-repository.worktribe.com/output/1703475
• Publisher URL: https://www.nature.com/articles/s41467-019-09870-y