Tracking subsurface active weathering processes in serpentinite

Tominaga, M., Ortiz, E., Einsle, J. F. , Ryoichi Vento, N. F., Schrenk, M. O., Buisman, I., Ezad, I. S. and Cardace, D. (2021) Tracking subsurface active weathering processes in serpentinite. Geophysical Research Letters, 48(6), e2020GL088472. (doi: 10.1029/2020GL088472)

Abstract

We conducted a novel study to capture the on‐going advancement of mineral weathering within a serpentinite formation by using an integrated approach of multi‐scale quantitative rock magnetic analyses and nano‐resolution geochemical imaging analyses. We studied a suite of rock samples from the Coast Range Ophiolite Microbial Observatory (CROMO) in California to conduct rock magnetic analyses enabling us to determine character of Fe‐bearing minerals and to predict locations of reaction boundaries among various stages of weathering. QEMSCAN® and other electron micro‐imagery analyses highlighted microstructural changes in amorphous minerals, and possible changes in porosity and coincides with the iron‐enrichment region. This iron enrichment indicates initiation of iron (‐oxides) nucleation, resulting in extremely fine gain magnetite formation. This is a newly documented mode of magnetite production in serpentinites and enhances the application of magnetite abundance as a proxy for the degree and extent of water‐rock interaction in mantle peridotite and serpentinite.

• Item Type: Articles
• Additional Information: We thank the Institute of Rock Magnetism of University of Minnesota for Undergraduate Student Fellowships for Ortiz and Vento over two separate award years in supporting the comprehensive rock magnetic analyses, part of which contributed to this funded project. This study was supported by Rock Powered Life grant (NASA Astrobiology Institute) NNA15BB02A. J.F.E. acknowledges funding under ERC Advanced Grant 320750-Nanopaleomagnetism.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Einsle, Dr Joshua Franz
• Authors: Tominaga, M., Ortiz, E., Einsle, J. F., Ryoichi Vento, N. F., Schrenk, M. O., Buisman, I., Ezad, I. S., and Cardace, D.
• College/School: College of Science and Engineering > School of Geographical and Earth Sciences > Earth Sciences
• Journal Name: Geophysical Research Letters
• Publisher: Wiley
• ISSN: 0094-8276
• ISSN (Online): 1944-8007
• Published Online: 19 January 2021
• Copyright Holders: Copyright © 2021 American Geophysical Union
• First Published: First published in Geophysical Research Letters 48(6): e2020GL088472
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher