Deep Sourced Fluids for Peridotite Carbonation in the Shallow Mantle Wedge of a Fossil Subduction Zone: Sr and C Isotope Profiles of OmanDP Hole BT1B

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.

[1]  K. Michibayashi,et al.  Geochemical Profiles Across the Listvenite‐Metamorphic Transition in the Basal Megathrust of the Semail Ophiolite: Results From Drilling at OmanDP Hole BT1B , 2021, Journal of Geophysical Research: Solid Earth.

[2]  K. Michibayashi,et al.  Listvenite Formation During Mass Transfer into the Leading Edge of the Mantle Wedge: Initial Results from Oman Drilling Project Hole BT1B , 2022, Journal of Geophysical Research: Solid Earth.

[3]  D. Stockli,et al.  Structural and Thermal Evolution of an Infant Subduction Shear Zone: Insights From Sub‐Ophiolite Metamorphic Rocks Recovered From Oman Drilling Project Site BT‐1B , 2021, Journal of geophysical research. Solid earth.

[4]  D. Zeko.  Carbonation of the Oman Ophiolite during subduction and emplacement , 2021 .

[5]  J. Ague,et al.  Pervasive subduction zone devolatilization recycles CO2 into the forearc , 2020, Nature Communications.

[6]  S. Humphris,et al.  Brucite formation and dissolution in oceanic serpentinite , 2020 .

[7]  P. Kelemen,et al.  Brittle Deformation of Carbonated Peridotite—Insights From Listvenites of the Samail Ophiolite (Oman Drilling Project Hole BT1B) , 2020, Journal of Geophysical Research: Solid Earth.

[8]  P. Kelemen,et al.  A Mg Isotopic Perspective on the Mobility of Magnesium During Serpentinization and Carbonation of the Oman Ophiolite , 2020, Journal of Geophysical Research: Solid Earth.

[9]  P. Kelemen,et al.  Major element mobility during serpentinization, oxidation and weathering of mantle peridotite at low temperatures , 2020, Philosophical Transactions of the Royal Society A.

[10]  M. Leybourne,et al.  Carbonation of ophiolitic ultramafic rocks: Listvenite formation in the Late Cretaceous ophiolites of eastern Iran , 2020 .

[11]  M. Ziegler,et al.  Ultramafic Rock Carbonation: Constraints From Listvenite Core BT1B, Oman Drilling Project , 2019, Journal of Geophysical Research: Solid Earth.

[12]  P. Gouze,et al.  Evidence of polygenetic carbon trapping in the Oman Ophiolite: Petro-structural, geochemical, and carbon and oxygen isotope study of the Wadi Dima harzburgite-hosted carbonates (Wadi Tayin massif, Sultanate of Oman) , 2018, Lithos.

[13]  C. Garrido,et al.  Carbonation of mantle peridotite by CO2-rich fluids: the formation of listvenites in the Advocate ophiolite complex (Newfoundland, Canada) , 2018, Lithos.

[14]  B. Dubacq,et al.  Mantle Wedge (De)formation During Subduction Infancy: Evidence from the Base of the Semail Ophiolitic Mantle , 2018, Journal of Petrology.

[15]  P. Kelemen,et al.  Fluid rock interactions on residual mantle peridotites overlain by shallow oceanic limestones: Insights from Wadi Fins, Sultanate of Oman , 2018, Chemical Geology.

[16]  R. Littke,et al.  Tectono-thermal evolution of Oman's Mesozoic passive continental margin under the obducting Semail Ophiolite: a case study of Jebel Akhdar, Oman , 2018, Solid Earth.

[17]  B. Dubacq,et al.  Petrological evidence for stepwise accretion of metamorphic soles during subduction infancy (Semail ophiolite, Oman and UAE) , 2017 .

[18]  A. Boyce,et al.  Carbonate alteration of ophiolitic rocks in the Arabian–Nubian Shield of Egypt: sources and compositions of the carbonating fluid and implications for the formation of Au deposits , 2017 .

[19]  K. Maher,et al.  Clumped-isotope thermometry of magnesium carbonates in ultramafic rocks , 2016 .

[20]  P. Kelemen,et al.  Synchronous formation of the metamorphic sole and igneous crust of the Semail ophiolite: New constraints on the tectonic evolution during ophiolite formation from high-precision U–Pb zircon geochronology , 2016 .

[21]  M. Cathelineau,et al.  Paired stable isotopes (O, C) and clumped isotope thermometry of magnesite and silica veins in the New Caledonia Peridotite Nappe , 2016 .

[22]  E. Gazel,et al.  Sulfur and carbon geochemistry of the Santa Elena peridotites: Comparing oceanic and continental processes during peridotite alteration , 2016 .

[23]  P. Kelemen,et al.  Geochemistry and petrology of listvenite in the Samail ophiolite, Sultanate of Oman: Complete carbonation of peridotite during ophiolite emplacement , 2015 .

[24]  P. Kelemen,et al.  Reevaluating carbon fluxes in subduction zones, what goes down, mostly comes up , 2015, Proceedings of the National Academy of Sciences.

[25]  A. Ueda,et al.  Melt extraction and metasomatism recorded in basal peridotites above the metamorphic sole of the northern Fizh massif, Oman ophiolite , 2015 .

[26]  A. Tamura,et al.  Chemical variations of abyssal peridotites in the central Oman ophiolite: Evidence of oceanic mantle heterogeneity , 2014 .

[27]  J. Horita.  Oxygen and carbon isotope fractionation in the system dolomite–water–CO2 to elevated temperatures , 2014 .

[28]  M. Searle,et al.  Structure of the metamorphic sole to the Oman Ophiolite, Sumeini Window and Wadi Tayyin: implications for ophiolite obduction processes , 2014 .

[29]  Stefano M. Bernasconi,et al.  Serpentinization and carbon sequestration: A study of two ancient peridotite-hosted hydrothermal systems , 2013 .

[30]  R. Miller,et al.  Tectonic development of the Samail ophiolite: High‐precision U‐Pb zircon geochronology and Sm‐Nd isotopic constraints on crustal growth and emplacement , 2013 .

[31]  Charles H. Langmuir,et al.  The mean composition of ocean ridge basalts , 2013 .

[32]  L. Crispini,et al.  The role of serpentinites in cycling of carbon and sulfur: Seafloor serpentinization and subduction metamorphism , 2012 .

[33]  B. Jamtveit,et al.  Massive serpentinite carbonation at Linnajavri, N–Norway , 2012 .

[34]  M. L. Collier.  Spatial-Statistical Properties of Geochemical Variability as Constraints on Magma Transport and Evolution Processes at Ocean Ridges , 2012 .

[35]  H. Paulick,et al.  Carbonate veins trace seawater circulation during exhumation and uplift of mantle rock: Results from ODP Leg 209 , 2011 .

[36]  C. Garrido,et al.  Thermodynamic constraints on mineral carbonation of serpentinized peridotite , 2011 .

[37]  John Frederick Rudge,et al.  Rates and mechanisms of mineral carbonation in peridotite: natural processes and recipes for enhanced, in situ CO2 capture and storage , 2011 .

[38]  P. Kelemen,et al.  Composition and Genesis of Depleted Mantle Peridotites from the Wadi Tayin Massif, Oman Ophiolite; Major and Trace Element Geochemistry, and Os Isotope and PGE Systematics , 2010 .

[39]  Peter B. Kelemen,et al.  In situ carbonation of peridotite for CO2 storage , 2008, Proceedings of the National Academy of Sciences.

[40]  D. Kelley,et al.  Carbon geochemistry of serpentinites in the Lost City Hydrothermal System (30°N, MAR) , 2008 .

[41]  J. Nakajima,et al.  Tomographic evidence for hydrated oceanic crust of the Pacific slab beneath northeastern Japan: Implications for water transportation in subduction zones , 2008 .

[42]  D. Wiens,et al.  Seismic evidence for widespread serpentinized forearc mantle along the Mariana convergence margin , 2008 .

[43]  S. Nasir,et al.  Mineralogical and geochemical characterization of listwaenite from the Semail Ophiolite, Oman , 2007 .

[44]  H. Paulick,et al.  Geochemistry of abyssal peridotites (Mid-Atlantic Ridge, 15°20'N, ODP Leg 209): Implications for fluid/rock interaction in slow spreading environments , 2006 .

[45]  M. Polvé,et al.  Along‐ridge petrological segmentation of the mantle in the Oman ophiolite , 2006 .

[46]  B. Kieffer,et al.  High‐precision isotopic characterization of USGS reference materials by TIMS and MC‐ICP‐MS , 2006 .

[47]  J. Connolly,et al.  Modeling open system metamorphic decarbonation of subducting slabs , 2006 .

[48]  R. Blakely,et al.  Subduction-zone magnetic anomalies and implications for hydrated forearc mantle , 2005 .

[49]  G. Dipple,et al.  CARBONATED SERPENTINITE (LISTWANITE) AT ATLIN, BRITISH COLUMBIA: A GEOLOGICAL ANALOGUE TO CARBON DIOXIDE SEQUESTRATION , 2005 .

[50]  D. Kelley,et al.  Serpentinization of Oceanic Peridotites: Implications for Geochemical Cycles and Biological Activity , 2013 .

[51]  S. Schwartz,et al.  Evidence for serpentinization of the forearc mantle wedge along the Nicoya Peninsula, Costa Rica , 2004 .

[52]  P. Deines.  Carbon isotope effects in carbonate systems , 2004 .

[53]  A. Hofmann.  Sampling mantle heterogeneity through oceanic basalts: Isotopes and trace elements , 2003 .

[54]  Simon M. Peacock,et al.  Serpentinization of the forearc mantle , 2003 .

[55]  P. Kelemen,et al.  Dunite distribution in the Oman Ophiolite: Implications for melt flux through porous dunite conduits , 2002 .

[56]  P. Deines.  The carbon isotope geochemistry of mantle xenoliths , 2002 .

[57]  M. Searle,et al.  Subduction zone metamorphism during formation and emplacement of the Semail ophiolite in the Oman Mountains , 2002, Geological Magazine.

[58]  Laure Gerbert-Gaillard.  Caractérisation Géochimique des Péridotites de l'ophiolite d'Oman : processus magmatiques aux limites lithosphère/asthenosphère , 2002 .

[59]  A. Wilde,et al.  Preliminary study of Cenozoic hydrothermal alteration and platinum deposition in the Oman Ophiolite , 2002 .

[60]  J. Connolly,et al.  Metamorphic devolatilization of subducted marine sediments and the transport of volatiles into the Earth's mantle , 2001, Nature.

[61]  R. Howarth,et al.  Strontium Isotope Stratigraphy: LOWESS Version 3: Best Fit to the Marine Sr‐Isotope Curve for 0–509 Ma and Accompanying Look‐up Table for Deriving Numerical Age , 2001, The Journal of Geology.

[62]  J. Bodinier,et al.  Relationships between geochemistry and structure beneath a palaeo-spreading centre: a study of the mantle section in the Oman ophiolite , 2000 .

[63]  Shin'ichiro Kamiya,et al.  Seismological evidence for the existence of serpentinized wedge mantle , 2000 .

[64]  E. Gnos,et al.  Rapid emplacement of the Oman ophiolite: Thermal and geochronologic constraints , 1996 .

[65]  B. Hacker,et al.  Metamorphism and deformation along the emplacement thrust of the Samail ophiolite, Oman , 1996 .

[66]  C. Halls,et al.  Listvenite and related rocks: perspectives on terminology and mineralogy with reference to an occurrence at Cregganbaun, Co. Mayo, Republic of Ireland , 1995 .

[67]  B. Hacker.  Rapid Emplacement of Young Oceanic Lithosphere: Argon Geochronology of the Oman Ophiolite , 1994, Science.

[68]  M. Searle,et al.  Structure and metamorphism of blueschist–eclogite facies rocks from the northeastern Oman Mountains , 1994, Journal of the Geological Society.

[69]  R. Clayton,et al.  Oxygen and carbon isotope fractionations between CO2 and calcite , 1991 .

[70]  I. Clark,et al.  Paleoclimatic Reconstruction in Northern Oman Based on Carbonates from Hyperalkaline Groundwaters , 1990, Quaternary Research.

[71]  M. Beurrier,et al.  The Hawasina Nappes: stratigraphy, palaeogeography and structural evolution of a fragment of the south-Tethyan passive continental margin , 1990, Geological Society, London, Special Publications.

[72]  M. Beurrier,et al.  The Hawasina Basin: A fragment of a starved passive continental margin, thrust over the Arabian Platform during obduction of the Sumail Nappe , 1988 .

[73]  F. Boudier,et al.  Shear zones, thrusts and related magmatism in the Oman ophiolite: Initiation of thrusting on an oceanic ridge , 1988 .

[74]  W. Fyfe,et al.  Rate of serpentinization in seafloor environments , 1985 .

[75]  G. Stanger.  Silicified serpentinite in the Semail nappe of Oman , 1985 .

[76]  Robert A. Duncan,et al.  A captured island chain in the coast range of Oregon and Washington , 1982 .

[77]  G. Wasserburg,et al.  Sm‐Nd, Rb‐Sr, and 18O/16O isotopic systematics in an oceanic crustal section: Evidence from the Samail Ophiolite , 1981 .

[78]  R. Coleman,et al.  Sr isotopic tracer study of the Samail ophiolite, Oman. , 1981 .

[79]  J. Malpas,et al.  Structure and metamorphism of rocks beneath the Semail ophiolite of Oman and their significance in ophiolite obduction , 1980, Transactions of the Royal Society of Edinburgh: Earth Sciences.