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Subarctic weathering of mineral wastes provides a sink for atmospheric CO2
journal contribution
posted on 2023-05-19, 23:01 authored by Wilson, SA, Dipple, GM, Power, IM, Shaun BarkerShaun Barker, Fallon, SJ, Southam, GThe mineral waste from some mines has the capacity to trap and store CO2 within secondary carbonate minerals via the process of silicate weathering. Nesquehonite [MgCO3·3H2O] forms by weathering of Mg-silicate minerals in kimberlitic mine tailings at the Diavik Diamond Mine, Northwest Territories, Canada. Less abundant Na- and Ca-carbonate minerals precipitate from sewage treatment effluent deposited in the tailings storage facility. Radiocarbon and stable carbon and oxygen isotopes are used to assess the ability of mine tailings to trap and store modern CO2 within these minerals in the arid, subarctic climate at Diavik. Stable isotopic data cannot always uniquely identify the source of carbon stored within minerals in this setting; however, radiocarbon isotopic data provide a reliable quantitative estimate for sequestration of modern carbon. At least 89% of the carbon trapped within secondary carbonate minerals at Diavik is derived from a modern source, either by direct uptake of atmospheric CO2 or indirect uptake though the biosphere. Silicate weathering at Diavik is trapping 102-114 g C/m2/y within nesquehonite, which corresponds to a 2 orders of magnitude increase over the background rate of CO2 uptake predicted from arctic and subarctic river catchment data.
History
Publication title
Environmental Science and TechnologyVolume
45Issue
18Pagination
7727-7736ISSN
0013-936XDepartment/School
School of Natural SciencesPublisher
Amer Chemical SocPlace of publication
1155 16Th St, Nw, Washington, USA, Dc, 20036Rights statement
Copyright 2011 American Chemical SocietyRepository Status
- Restricted