Supra-subduction and abyssal mantle peridotites of the Coast Range ophiolite, California

Choi, Sung Hi; Shervais, John W.; Mukasa, Samuel B.

doi:10.1007/s00410-008-0300-6

Cited by 161 publications

(95 citation statements)

References 63 publications

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“…The highest depletion of the mantle rocks is inferred in an arc tectonic setting and/or in a supra-subduction zone environment (e.g. Arai 1994;Choi et al 2008). The Cr# of spinel in abyssal peridotites collected from midocean ridges is less than 0.6 (Tamura & Arai 2006).…”

Section: Discussionmentioning

confidence: 99%

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Petrology and geochemistry of a peridotite body in Central- Carpathian Paleogene sediments (Sedlice, eastern Slovakia)

Koppa¹,

Koller²,

Putiš³

2014

Geologica Carpathica

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Abstract:We studied representative samples from a peridotite body situated NE of Sedlice village within the CentralCarpathian Paleogene sediments in the Central Western Carpathians. The relationship of the peridotite to the surrounding Paleogene sediments is not clear. The fractures of the brecciated peridotite margin are healed with secondary magnesite and calcite. On the basis of the presented bulk-rock and electron microprobe data, the wt. % amounts of mineral phases were calculated. Most of calculated "modal" compositions of this peridotite corresponds to harzburgites composed of olivine (~70-80 wt. %), orthopyroxene (~17-24 wt. %), clinopyroxene ( < 5 wt. %) and minor spinel ( < 1 wt. %). Harzburgites could originate from lherzolitic protoliths due to a higher degree of partial melting. Rare lherzolites contain porphyroclastic 1-2 mm across orthopyroxene (up to 25 wt. %), clinopyroxene (~5-8 wt. %) and minor spinel ( < 0.75 wt. %). On the other hand, rare, olivine-rich dunites with scarce orthopyroxene porphyroclasts are associated with harzburgites. Metamorphic mineral assemblage of low-Al clinopyroxene (3), tremolite, chrysotile, andradite, Cr-spinel to chromite and magnetite, and an increase of fayalite component in part of olivine, indicate low-temperature metamorphic overprint. The Primitive Mantle normalized whole-rock REE patterns suggest a depleted mantle rock-suite. An increase in LREE and a positive Eu anomaly may be consequence of interactive metamorphic fluids during serpentinization. Similar rocks have been reported from the Meliatic Bôrka Nappe overlying the Central Western Carpathians orogenic wedge since the Late Cretaceous, and they could be a potential source of these peridotite blocks in the Paleogene sediments.

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Section: Discussionmentioning

confidence: 99%

“…8a). Olivine composition is in correlation with spinel; spinel Cr# increases and spinel Mg# decreases as olivine Fo increases in the OSMA (Choi et al 2008).…”

Section: Microprobe Mineral Composition and Whole-rock Chemical Datamentioning

confidence: 95%

Petrology and geochemistry of a peridotite body in Central- Carpathian Paleogene sediments (Sedlice, eastern Slovakia)

Koppa¹,

Koller²,

Putiš³

2014

Geologica Carpathica

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“…Most pyroxenes in SSZ peridotites are characterized by extremely low minor-element (Al, Ti) contents compared to the abyssal peridotites, but generally have higher Mg# (Choi et al 2008). Average Mg# in Kermanshah orthopyroxenes and clinopyroxenes are 0.95 and 0.93 respectively (Tabs 3 and 4).…”

Section: Melt/rock Reactionmentioning

confidence: 98%

Textural records and geochemistry of the Kermanshah mantle peridotites (Iran): implications for the tectonic evolution of southern Neo-Tethys

Moradpour¹,

Sahamieh²,

Khalaji³

et al. 2017

J. Geosci.

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Kermanshah Ophiolite Complex (NW Iran), located along the Main Zagros Thrust Zone, marks the ophiolitic suture between the Arabian and Sanandaj-Sirjan continental blocks. N-MORB-normalized multielement patterns and chondrite--normalized REE patterns in the Kermanshah mantle restites show depletion in incompatible elements concentrations with respect to the depleted MORB mantle (DMM). In the V vs. Yb diagram, Harsin-Sahneh-Norabad and Miyanrahan peridotites (Kermanshah Ophiolite Complex), due to their relatively low V contents, fall close to the QFM buffer. Calculated TiO 2 and Al 2 O 3 compositions in the parental melt that were in equilibrium with chromian spinel are consistent with supra-subduction zone-type compositions. Besides, calculated FeO/MgO ratios in the parental melts are comparable with those in boninites from Oman ophiolites. Olivine from the peridotite restites is highly magnesian (Fo 89-93 ) with NiO contents of 0.2-0.4 wt. %, consistent with formation in a forearc environment. This is also proven by the Cr# and Mg# values as well as TiO 2 , Cr 2 O 3 , and Al 2 O 3 concentrations in chromian spinel of ultramafic rocks. Accordingly, petrogenetic modeling indicates that the Kermanshah ultramafic rocks may represent the residual mantle after extraction of 13-23% of boninitic-type melts. Decompression, melting and melt-rock reaction related textures are widespread in the Kermanshah mantle restites. Field relationships and geochemical evidence reveal that the studied ophiolites were a part of a rifted basin at the ocean-continent transition zone formed in the south Neo-Tethyan Ocean.

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“…Mantle peridotites of the ophiolite complexes provide, however, important information on the process of melt generation, the relationship with the overlying crustal sections, and the influence of any mantle-melt interaction subsequent to melt extraction (e.g., Dick 1989;Johnson et al 1990;Hellebrand et al 2002;Seyler et al 2007;Choi et al 2008;Rollinson 2008;Caran et al 2010). Stern et al (2004) argued for the significance, and thus the need, of studying the mantle section of these ophiolites, especially their chromite compositions, for better characterization of their origin and evolution.…”

Section: Introductionmentioning

confidence: 98%

Petrogenetic and geotectonic significance of Neoproterozoic suprasubduction mantle as revealed by the Wizer ophiolite complex, Central Eastern Desert, Egypt

Farahat

Hoinkes

Mogessie

2010

Int J Earth Sci (Geol Rundsch)

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Ophiolite complexes, formed in a suprasubduction zone environment during Neoproterozoic time, are widely distributed in the Eastern Desert of Egypt. Their mantle sections provide important information on the origin and tectonic history of ocean basins these complexes represent. The geochemistry and mineralogy of the mantle section of the Wizer ophiolite complex, represented by serpentinites after harzburgite containing minor dunite bodies, are presented. Presence of antigorite together with the incipient alteration of chromite and absence of chlorite suggests that serpentinization occurred in the mantle wedge above a Neoproterozoic subduction zone. Wizer peridotites have a wide range of spinel compositions. Spinel Cr# [100Cr/(Cr ? Al)] decrease gradually from dunite bodies (Cr# = 81-87) and their host highly depleted harzburgites (Cr# = 67-79) to the less depleted harzburgites (Cr# = 57-63). Such decreases in mantle refractory character are accompanied by higher Al and Ti contents in bulk compositions. Estimated parental melt compositions point to an equilibration with melts of boninitic composition for the dunite bodies (TiO 2 = *\0.07-0.22 wt%; Al 2 O 3 = 9.4-10.6 wt%), boninitic-arc tholeiite for the highly depleted harzburgites (TiO 2 = \0.09-0.28 wt%; Al 2 O 3 = 11.2-14.1 wt%) and more MORB-like affinities for the less depleted harzburgites (TiO 2 = *\0.38-0.51 wt%; Al 2 O 3 = 14.5-15.3 wt%). Estimated equilibrium melts are found in the overlying volcanic sequence, which shows a transitional MORB-island arc geochemical signature with a few boninitic samples. Enrichment of some chromites in TiO 2 and identification of sulfides in highly depleted peridotites imply interaction with an impregnating melt. A two-stage partial melting/melt-rock reaction model is advocated, whereby, melting of a depleted mantle source by reaction with MORB-like melts is followed by a second stage melting by interaction with melts of IAT-boninitic affinities in a suprasubduction zone environment to generate the highly depleted harzburgites and dunite bodies. The shift from MORB to island arc/boninitic affinities within the mantle lithosphere of the Wizer ophiolite sequence suggests generation in a protoarc-forearc environment. This, together with the systematic latitudinal change in composition of ophiolitic lavas in the Central Eastern Desert (CED) of Egypt from IAT-boninitic affinities to more MORB-like signature, implies that the CED could represent a disrupted forearc-arc-backarc system above a southeast-dipping subduction zone.

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Supra-subduction and abyssal mantle peridotites of the Coast Range ophiolite, California

Cited by 161 publications

References 63 publications

Petrology and geochemistry of a peridotite body in Central- Carpathian Paleogene sediments (Sedlice, eastern Slovakia)

Petrology and geochemistry of a peridotite body in Central- Carpathian Paleogene sediments (Sedlice, eastern Slovakia)

Textural records and geochemistry of the Kermanshah mantle peridotites (Iran): implications for the tectonic evolution of southern Neo-Tethys

Petrogenetic and geotectonic significance of Neoproterozoic suprasubduction mantle as revealed by the Wizer ophiolite complex, Central Eastern Desert, Egypt

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