Mountain glaciation drives rapid oxidation of rock-bound organic carbon

Horan, K; Hilton, RG; Selby, D; Ottley, CJ; Gröcke, DR; Hicks, M; Burton, KW

Abstract

Over millions of years, the oxidation of organic carbon contained within sedimentary rocks is one of the main sources of carbon dioxide to the atmosphere, yet the controls on this emission remain poorly constrained. We use rhenium to track the oxidation of rock-bound organic carbon in the mountain watersheds of New Zealand, where high rates of physical erosion expose rocks to chemical weathering. Oxidative weathering fluxes are two to three times higher in watersheds dominated by valley glaciers and exposed to frost shattering processes, compared to those with less glacial cover; a feature that we also observe in mountain watersheds globally. Consequently, we show that mountain glaciation can result in an atmospheric carbon dioxide source during weathering and erosion, as fresh minerals are exposed for weathering in an environment with high oxygen availability. This provides a counter mechanism against global cooling over geological time scales.

Citation

Horan, K., Hilton, R., Selby, D., Ottley, C., Gröcke, D., Hicks, M., & Burton, K. (2017). Mountain glaciation drives rapid oxidation of rock-bound organic carbon. Science Advances, 3(10), Article e1701107. https://doi.org/10.1126/sciadv.1701107

• Journal Article Type: Article
• Acceptance Date: Sep 12, 2017
• Online Publication Date: Oct 4, 2017
• Publication Date: Oct 4, 2017
• Deposit Date: Sep 13, 2017
• Publicly Available Date: Oct 6, 2017
• Journal: Science Advances
• Electronic ISSN: 2375-2548
• Publisher: American Association for the Advancement of Science
• Peer Reviewed: Peer Reviewed
• Volume: 3
• Issue: 10
• Article Number: e1701107
• DOI: https://doi.org/10.1126/sciadv.1701107
• Public URL: https://durham-repository.worktribe.com/output/1349252