"Subsurface Landscapes of Oxidation and Reaction in the Critical Zone"
Presented by Susan Brantley, Pennsylvania State University, PA
Thursday, February 13, 2020, 4:00 pm — Large Seminar Room, Bldg. 510
The globally ubiquitous mineral pyrite oxidizes even at low oxygen concentrations. As the most common crustal sulfide, pyrite reactivity impacts sulfur, iron, oxygen, and carbon budgets globally. We discovered that pyrite oxidizes completely at tens of meters depth even in low-porosity rocks in catchments in humid climates. As erosion exposes the pyrite to near-surface conditions in low porosity rocks, pore and fracture development is the main control on the rate of oxidative weathering. Between fractures, oxygen diffusion limits the weathering and oxidation is inferred to be largely abiotic because bacteria cannot enter rock matrix pores. Oxygen concentrations and erosion rates together can explain pyrite-derived sulfate fluxes in rivers to the ocean and may account for the presence or absence of pyrite in detrital sediments over Earth history.
Hosted by: John Hill
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