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)

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dc.contributor.authorNoël, J.
dc.contributor.authorGodard, M
dc.contributor.authorOliot, E.
dc.contributor.authorMartinez, I.
dc.contributor.authorWilliams, Morgan
dc.contributor.authorBoudier, F.
dc.contributor.authorRodriguez, O.
dc.contributor.authorChaduteau, Carine
dc.contributor.authorEscario, S.
dc.contributor.authorGouze, P.
dc.date.accessioned2020-02-26T23:18:20Z
dc.date.issued2018
dc.date.updated2019-11-25T07:37:07Z
dc.description.abstractThe Wadi Dima area (Oman Ophiolite) exposes partially altered to highly serpentinized harzburgites that are cross-cut by intense (>20 Vol%) carbonate veining. We identified a sequence of 3 types of carbonate veins with compositions ranging from calcite to dolomite (Mg/Ca = 0-0.85). Type 1 carbonates occur as a fine diffuse vein network, locally replacing olivine cores, penetrative into the serpentinized harzburgites. They have depleted trace elements abundances (e.g., Yb < 0.2 × C1-chondrite) relative to other Wadi Dima carbonates, exhibit negative Ce and positive Y, U anomalies and a broad range in δ13CV-PDB (-5 to -15‰) and δ18OSMOW (18 to 31‰). These compositions are consistent with precipitation after seawater-derived fluids and/or fluids in equilibrium with mantle rocks and serpentines during cooling of oceanic lithosphere (110 to 15°C). Type 2 carbonates are localized in veins, which acted as main flow paths for fluids interacting with peridotites in the exhumed Oman mantle lithosphere (50°C-10°C). The orientation of these veins is controlled by the crystallographic anisotropy of Oman mantle peridotites. Type 2 carbonates record two stages. The first involved the formation of large calcite crystals of composition similar to Type 1 carbonates (trace element depleted; δ13CV-PDB B = -4 to -9‰ and δ18OSMOW = 26 to 30‰), which during the second stage were recrystallized to form dolomite and calcite microcrystals (trace element enriched; δ13CV-PDB = -7 to -13‰ and δ18OSMOW = 29 to 32‰), after fluids sampling different sources including contributions of sediment-derived components. They were most likely formed at shallow depths and record the transition from oceanic to continental settings during late Cretaceous ophiolite obduction. Type 3 veins reactivate Type 2 veins. They comprise dominantly calcite and dolomite microcrystals (Light REE enriched patterns) with isotopic compositions (δ13CV-PDB B ~ -7 to -8‰; δ18OSMOW~ 28 to 32‰) consistent with precipitation at low temperatures (T°<30°C) from surface/meteoric fluids. Type 3 veining is probably triggered by ophiolite uplift during the Oligocene to early Miocene. Our study presents new insights into the role of the initial mantle anisotropy in the orientation of the vein network and of principal flow paths during serpentinization and carbonatization of mantle peridotites. It also highlights the highly variable carbon isotope composition of carbonates and suggest different origins for these heterogeneities: the carbon isotope composition of the early Type 1 carbonates dispersed in the poorly connected peridotites is locally modified by serpentinization reactions whilst the carbon isotope compositions of Type 2 and 3 carbonates record mixing of fluids from different sources in high flow veins.en_AU
dc.description.sponsorshipThis study was funded by INSU CNRS Tellus project 2016 and Deep Carbon Observatory-Deep Energy community awarded by Alfred P. Sloan Foundation grant “In situ Oxygen and Carbone isotope in Oman Ophiolite basement: new insight of serpentinization, carbonatation and fluid circulation” (Sloan Subaward Number 2090 G UA721). High resolution X-ray microtomography images (ID19 beamline, ESRF, Grenoble, France) were acquired as part of ESRF Experiment ES-277. SE was supported by the People Programme (Marie Curie Actions) of the European Union's Seventh Framework ProgrammeFP7/ 2007-2013 under REA-Grant Agreement n608001.en_AU
dc.format.mimetypeapplication/pdfen_AU
dc.identifier.issn0024-4937en_AU
dc.identifier.urihttp://hdl.handle.net/1885/201933
dc.language.isoen_AUen_AU
dc.publisherElsevieren_AU
dc.rights© 2018 Elsevier B.Ven_AU
dc.sourceLithosen_AU
dc.titleEvidence 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)en_AU
dc.typeJournal articleen_AU
local.bibliographicCitation.lastpage237en_AU
local.bibliographicCitation.startpage218en_AU
local.contributor.affiliationNoël, J., University of Montpellieren_AU
local.contributor.affiliationGodard, M, Universite Montpellieren_AU
local.contributor.affiliationOliot, E., University of Montpellieren_AU
local.contributor.affiliationMartinez, I., Université Paris Dideroten_AU
local.contributor.affiliationWilliams, Morgan, College of Science, ANUen_AU
local.contributor.affiliationBoudier, F., University of Montpellieren_AU
local.contributor.affiliationRodriguez, O., Voxaya SASen_AU
local.contributor.affiliationChaduteau, Carine, Université Paris Dideroten_AU
local.contributor.affiliationEscario, S., University of Montpellieren_AU
local.contributor.affiliationGouze, P., University of Montpellieren_AU
local.contributor.authoremailrepository.admin@anu.edu.auen_AU
local.contributor.authoruidWilliams, Morgan, u4851731en_AU
local.description.embargo2037-12-31
local.description.notesImported from ARIESen_AU
local.identifier.absfor040202 - Inorganic Geochemistryen_AU
local.identifier.absfor040203 - Isotope Geochemistryen_AU
local.identifier.absfor040304 - Igneous and Metamorphic Petrologyen_AU
local.identifier.absseo970104 - Expanding Knowledge in the Earth Sciencesen_AU
local.identifier.ariespublicationu3102795xPUB315en_AU
local.identifier.citationvolume323en_AU
local.identifier.doi10.1016/j.lithos.2018.08.020en_AU
local.identifier.scopusID2-s2.0-85052912417
local.identifier.uidSubmittedByu3102795en_AU
local.publisher.urlhttps://www.elsevier.com/en-auen_AU
local.type.statusPublished Versionen_AU

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