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Tracking Subsurface Active Weathering Processes in Serpentinite
Author(s) -
Tominaga Masako,
Ortiz Estefania,
Einsle Joshua Franz,
Ryoichi Vento Noah Francis,
Schrenk Matthew O,
Buisman Iris,
Ezad Isra S.,
Cardace Dawn
Publication year - 2021
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl088472
Subject(s) - weathering , magnetite , geology , peridotite , geochemistry , mineralogy , rock magnetism , mineral , mantle (geology) , materials science , magnetization , metallurgy , paleontology , physics , quantum mechanics , magnetic field , remanence
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.