Listvenite Formation During Mass Transfer into the Leading Edge of the Mantle Wedge: Initial Results from Oman Drilling Project Hole BT1B

PB Kelemen, de Obeso J Carlos, James A. Leong, Marguerite Godard, Keishi Okazaki, Alissa J. Kotowski, CE Manning, Eric T. Ellison, Manuel D. Menzel, Janos L. Urai, Greg Hirth, Matthew Rioux, Daniel F. Stockli, Romain Lafay, Andreas M. Beinlich, JA Coggon, NH Warsi, Jürg M. Matter, DAH Teagle, M HarrisKatsuyoshi Michibayashi, Eiichi Takazawa, Sulaimani Z Al

Research output: Contribution to journalArticlepeer-review

Abstract

<jats:title>Abstract</jats:title><jats:p>This paper provides an overview of research on core from Oman Drilling Project Hole BT1B and the surrounding area, plus new data and calculations, constraining processes in the Tethyan subduction zone beneath the Samail ophiolite. The area is underlain by gently dipping, broadly folded layers of allochthonous Hawasina pelagic sediments, the metamorphic sole of the Samail ophiolite, and Banded Unit peridotites at the base of the Samail mantle section. Despite reactivation of some faults during uplift of the Jebel Akdar and Saih Hatat domes, the area preserves the tectonic “stratigraphy” of the Cretaceous subduction zone. Gently dipping listvenite bands, parallel to peridotite banding and to contacts between the peridotite and the metamorphic sole, replace peridotite at and near the basal thrust. Listvenites formed at less than 200°C and (poorly constrained) depths of 25–40 km by reaction with CO<jats:sub>2</jats:sub>‐rich, aqueous fluids migrating from greater depths, derived from devolatilization of subducting sediments analogous to clastic sediments in the Hawasina Formation, at 400°–500°. Such processes could form important reservoirs for subducted CO<jats:sub>2</jats:sub>. Listvenite formation was accompanied by ductile deformation of serpentinites and listvenites—perhaps facilitated by fluid‐rock reaction—in a process that could lead to aseismic subduction in some regions. Addition of H<jats:sub>2</jats:sub>O and CO<jats:sub>2</jats:sub>to the mantle wedge, forming serpentinites and listvenites, caused large increases in the solid mass and volume of the rocks. This may have been accommodated by fractures formed as a result of volume changes, mainly at a serpentinization front.</jats:p>
Original languageEnglish
Number of pages0
JournalJournal of Geophysical Research: Solid Earth
Volume127
Issue number2
Early online date28 Jan 2022
DOIs
Publication statusPublished - Feb 2022

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