Brittle Deformation of Carbonated Peridotite – Insights from Listvenites of the Samail Ophiolite (Oman Drilling Project Hole BT1B)
- Autor(en)
- , Manuel D. Menzel, Janos L. Urai, Juan Carlos de Obeso, Alissa Kotowski, Craig E. Manning, Peter B. Kelemen, Michael Kettermann, Ana P. Jesus, Yumiko Harigane
- Abstrakt
Hole BT1B of the Oman Drilling Project provides a continuous sampling from listvenite into the metamorphic sole that preserves the deformation, hydration and carbonation processes of oceanic mantle peridotite at the base of the Samail ophiolite, Oman. We present evidence of multistage brittle deformation in listvenites and serpentinites based on field observations, visual core logging and petrography. About 10 vol% of listvenite and serpentinite in Hole BT1B is composed of cataclasite bands. Cataclasites contain lithic clasts of listvenite with spheroidal, zoned magnesite and quartz, and fragments of chalcedony‐carbonate veins that elsewhere crosscut listvenite — showing that cataclasis post‐dates listvenite formation. Locally the cataclasites are reworked and cut by thin, sharp faults, pointing to repeated reactivation of brittle structures. SEM‐EDS mapping shows that cataclasis was related to dissolution of carbonate and/or silica cementation. Dolomite veins crosscut cataclasites and breccias, suggesting that part of the Ca gain in BT1B is related to late fluids after listvenite formation. These results indicate a multistage tectonic overprint after peridotite carbonation and listvenite formation, which may be related to the tectonic history of the deformed continental margin under the ophiolite. These relatively late brittle structures should be excluded when trying to understand the carbonation of peridotite to listvenite.
- Organisation(en)
- Institut für Geologie
- Externe Organisation(en)
- Rheinisch-Westfälische Technische Hochschule Aachen, German University of Technology in Oman, Columbia University in the City of New York, University of Texas, Austin, McGill University, University of California, Los Angeles, Universidade de Lisboa, National Institute of Advanced Industrial Science and Technology (AIST)
- Journal
- Journal of Geophysical Research: Solid Earth
- Band
- 125
- Anzahl der Seiten
- 19
- ISSN
- 2169-9313
- DOI
- https://doi.org/10.1029/2020JB020199
- Publikationsdatum
- 10-2020
- Peer-reviewed
- Ja
- ÖFOS 2012
- 105106 Geodynamik, 105101 Allgemeine Geologie
- Schlagwörter
- ASJC Scopus Sachgebiete
- Geochemistry and Petrology, Geophysics, Earth and Planetary Sciences (miscellaneous), Space and Planetary Science
- Link zum Portal
- https://ucrisportal.univie.ac.at/de/publications/c81f35f3-69e9-4115-b4e1-aa6e79547673