TY - JOUR

T1 - Deep Sourced Fluids for Peridotite Carbonation in the Shallow Mantle Wedge of a Fossil Subduction Zone

T2 - Sr and C Isotope Profiles of OmanDP Hole BT1B

AU - Oman Drilling Project Phase 1 Science Party

AU - de Obeso, Juan Carlos

AU - Kelemen, Peter B.

AU - Leong, James M.

AU - Menzel, Manuel D.

AU - Manning, Craig E.

AU - Godard, Marguerite

AU - Cai, Yue

AU - Bolge, Louise

AU - Matter, Jürg

AU - Teagle, Damon

AU - Coggon, Jude

AU - Harris, Michelle

AU - Bennett, Emma

AU - Bompard, Nico

AU - Boulanger, Marine

AU - France, Lyderic

AU - Früh-Green, Gretchen

AU - Garbe-Schönberg, Dieter

AU - Ildefonse, Benoit

AU - Jesus, Ana

AU - Koepke, Jürgen

AU - Koornneef, Louise

AU - Lafay, Romain

AU - Lissenberg, Johan

AU - MacLeod, Chris

AU - Mock, Dominik

AU - Morris, Tony

AU - Müller, Samuel

AU - Noël, Julie

AU - Nothaft, Daniel

AU - Perez, Americus

AU - Pezard, Philippe

AU - Warsi, Nehal

AU - Zeko, David

AU - Zihlmann, Barbara

AU - Bechkit, Mohamed Amine

AU - Brun, Laurent

AU - Célérier, Bernard

AU - Henry, Gilles

AU - Paris, Jehanne

AU - Lods, Gérard

AU - Robert, Pascal

AU - Al Amri, Salim

AU - Al Shukaili, Mohsin

AU - Al Qassabi, Ali

AU - Moe, Kyaw

AU - Yamada, Yasu

AU - Takazawa, Eiichi

AU - Michibayashi, Katsuyoshi

AU - Abe, Natsue

N1 - Funding Information: JCO wants to thank Steven Goldstein for allowing early access to the laboratories in LDEO to complete isotope work soon after partial reopening following the first wave of the COVID-19 pandemic in New York. Wei Huang is thanked for help with measurements of carbon concentrations and δ13C. The authors thank Mark Dekkers for editorial handling. Constructive comments from an anonymous Associate Editor, Arman Boskabadi, and an anonymous reviewer helped to improve earlier versions of this manuscript. This research used samples and/or data provided by the Oman Drilling Project. The Oman Drilling Project (OmanDP) has been possible through co-mingled funds from the International Continental Scientific Drilling Project (ICDP; Kelemen, Matter, Teagle Lead PIs), the Sloan Foundation–Deep Carbon Observatory (Grant 2014-3-01, Kelemen PI), the National Science Foundation (NSF-EAR-1516300, Kelemen lead PI), NASA–Astrobiology Institute (NNA15BB02 A, Templeton PI), the German Research Foundation (DFG: KO 1723/21-1, Koepke PI), the Japanese Society for the Promotion of Science (JSPS no:16H06347, Michibayashi PI; and KAKENHI 16H02742, Takazawa PI), the European Research Council (Adv: no.669972; Jamveit PI), the Swiss National Science Foundation (SNF:20FI21_163073, Früh-Green PI), JAMSTEC, the TAMU-JR Science Operator, and contributions from the Sultanate of Oman Ministry of Regional Municipalities and Water Resources, the Oman Public Authority of Mining, Sultan Qaboos University, CNRS-Univ. Montpellier, Columbia University of New York, and the University of Southampton. This research was undertaken thanks in part to funding from the Canada First Research Excellence Fund for JCO.

PY - 2022/1/12

Y1 - 2022/1/12

N2 - Completely carbonated peridotites represent a window to study reactions of carbon-rich fluids with mantle rocks. Here, we present details on the carbonation history of listvenites close to the basal thrust in the Samail ophiolite. We use samples from Oman Drilling Project Hole BT1B, which provides a continuous record of lithologic transitions, as well as outcrop samples from listvenites, metasediments, and metamafics below the basal thrust of the ophiolite. 87Sr/86Sr of listvenites and serpentinites, ranging from 0.7090 to 0.7145, are significantly more radiogenic than mantle values, Cretaceous seawater, and other peridotite hosted carbonates in Oman. The Hawasina sediments that underlie the ophiolite, on the other hand, show higher 87Sr/86Sr values of up to 0.7241. δ13C values of total carbon in the listvenites and serpentinites range from −10.6‰ to 1.92‰. We also identified a small organic carbon component with δ13C as low as −27‰. Based on these results, we propose that during subduction at temperatures above >400°C, carbon-rich fluids derived from decarbonation of the underlying sediments migrated updip and generated the radiogenic 87Sr/86Sr signature and the fractionated δ13C values of the serpentinites and listvenites in core BT1B.

AB - Completely carbonated peridotites represent a window to study reactions of carbon-rich fluids with mantle rocks. Here, we present details on the carbonation history of listvenites close to the basal thrust in the Samail ophiolite. We use samples from Oman Drilling Project Hole BT1B, which provides a continuous record of lithologic transitions, as well as outcrop samples from listvenites, metasediments, and metamafics below the basal thrust of the ophiolite. 87Sr/86Sr of listvenites and serpentinites, ranging from 0.7090 to 0.7145, are significantly more radiogenic than mantle values, Cretaceous seawater, and other peridotite hosted carbonates in Oman. The Hawasina sediments that underlie the ophiolite, on the other hand, show higher 87Sr/86Sr values of up to 0.7241. δ13C values of total carbon in the listvenites and serpentinites range from −10.6‰ to 1.92‰. We also identified a small organic carbon component with δ13C as low as −27‰. Based on these results, we propose that during subduction at temperatures above >400°C, carbon-rich fluids derived from decarbonation of the underlying sediments migrated updip and generated the radiogenic 87Sr/86Sr signature and the fractionated δ13C values of the serpentinites and listvenites in core BT1B.

KW - listvenite

KW - Oman

KW - Oman Drilling Project

KW - ophiolite

KW - peridotite

KW - serpentinization

UR - http://www.scopus.com/inward/record.url?scp=85131386836&partnerID=8YFLogxK

U2 - 10.1029/2021JB022704

DO - 10.1029/2021JB022704

M3 - Article

AN - SCOPUS:85131386836

VL - 127

JO - Journal of Geophysical Research: Solid Earth

JF - Journal of Geophysical Research: Solid Earth

SN - 2169-9313

IS - 1

M1 - e2021JB022704

ER -