Abstract
Manganese oxides are ubiquitous marine minerals which are redox sensitive. As major components of manganese nodules found on the ocean floor, birnessite and buserite have been known to be two distinct water-containing minerals with manganese octahedral interlayer separations of ~7 Å and ~10 Å, respectively. We show here that buserite is a super-hydrated birnessite formed near 5 km depth conditions. As one of the most hydrous minerals containing ca. 34.5 wt. % water, super-hydrated birnessite, i.e., buserite, remains stable up to ca. 70 km depth conditions, where it transforms into manganite by releasing ca. 24.3 wt. % water. Subsequent transformations to hausmannite and pyrochroite occur near 100 km and 120 km depths, respectively, concomitant with a progressive reduction of Mn4+ to Mn2+. Our work forwards an abiotic geochemical cycle of manganese minerals in subduction and/or other aqueous terrestrial environments, with implications for water storage and cycling, and the redox capacity of the region.
Original language | English |
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Article number | 1942 |
Journal | Nature communications |
Volume | 13 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2022 Dec |
Bibliographical note
Funding Information:This work was supported by the Leader Researcher program (NRF-2018R1A3B1052042) of the Korean Ministry of Science and ICT. Ex-situ synchrotron experiments were performed at the 3D and 6D beamlines at the Pohang Light Source II (PLS II) at the Pohang Accelerator Laboratory (PAL) with support in part by MSIP, POSTECH, and UNIST Central Research facilities, and BL-18C beamline at Photon Factory (PF). In-situ synchrotron experiments were performed 13-BM-C beamline at Advanced Photon Source (APS), which is supported by GSECARS (NSF EAR-1634415 and DOE DE-FG02-94ER14466) and COMPRES (NSF EAR-1606856).
Funding Information:
This work was supported by the Leader Researcher program (NRF-2018R1A3B1052042) of the Korean Ministry of Science and ICT. Ex-situ synchrotron experiments were performed at the 3D and 6D beamlines at the Pohang Light Source II (PLS II) at the Pohang Accelerator Laboratory (PAL) with support in part by MSIP, POSTECH, and UNIST Central Research facilities, and BL-18C beamline at Photon Factory (PF). In-situ synchrotron experiments were performed 13-BM-C beamline at Advanced Photon Source (APS), which is supported by GSECARS (NSF EAR-1634415 and DOE DE-FG02-94ER14466) and COMPRES (NSF EAR-1606856).
Publisher Copyright:
© 2022, The Author(s).
All Science Journal Classification (ASJC) codes
- Chemistry(all)
- Biochemistry, Genetics and Molecular Biology(all)
- General
- Physics and Astronomy(all)