Coexistence of MORB and OIB-type mafic volcanics in the Manipur Ophiolite Complex, Indo-Myanmar Orogenic Belt, northeast India: Implication for heterogeneous mantle source at the spreading zone

Khogenkumar, Shoraisam; Singh, Alka; Singh, Rakesh Kumar; Khanna, P. P.; Singh, N. Ibotombi; Singh, W. Inaocha

doi:10.1016/j.jseaes.2015.11.007

Cited by 47 publications

(49 citation statements)

References 71 publications

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“…Even the large ion lithophile element (LILE, e.g., Rb, Ba, K, Sr, Pb, and Cs) contents of the accreted basalts exhibit no meaningful trends (Table S1), which is indicative of their diverse mobilization during hydrothermal alteration and metamorphism (Khogenkumar et al, 2016;Safonova et al, 2016;Said & Kerrich, 2009;Saito et al, 2015;Shervais, 1982). In contrast, based on many studies of Archean rocks and seafloor basalts, it is well accepted that Al 2 O 3 , TiO 2 , P 2 O 5 , high field-strength elements (HFSE, e.g., Th, Nb, Ta, Zr, Hf, Y, and REEs), and some transition elements (e.g., Ni, Cr, Co, Sc, and V) are relatively immobile during 10.1029/2018JB016562 Journal of Geophysical Research: Solid Earth metamorphism and alteration (Beccaluva et al, 1979;Bi et al, 2017;Pearce & Norry, 1979;Said & Kerrich, 2009).…”

Section: Effects Of Alteration and Metamorphism On Element Mobilitymentioning

confidence: 99%

Geochemistry and Geochronology of the Accreted Mafic Rocks From the Hengchun Peninsula, Southern Taiwan: Origin and Tectonic Implications

et al. 2019

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The accretionary prism of the Hengchun Peninsula at the southernmost tip of the active Taiwan orogen has newly emerged due to the transition from a subduction zone to an arc‐continent collision zone. The mafic rocks within the Hengchun accretionary prism, whose provenance has long been controversial, are highly indicative of the mantle nature and tectonic evolution around the northern Manila Trench. Based on geochemical analyses, the accreted basalts are classified as normal and enriched mid‐ocean ridge basalts (N‐MORB and E‐MORB) and alkaline ocean island basalts. The N‐MORBs, which exhibit geochemical signatures indicative of virtually unmetasomatized depleted MORB mantle and yield zircon U‐Pb ages of 22.8 ± 0.3 and 24.2 ± 1.1 Ma, were off‐scraped from the subducted oceanic crust of the South China Sea (SCS). The alkaline ocean island basalts are considered fragments of subducted seamount due to their geochemical similarity with seamount basalts from the SCS. The Hf‐Nd isotopic compositions of basalts from the north SCS may represent the contributions of recycled oceanic crust and the upwelling Hainan Plume. The E‐MORBs, which exhibit similar geochemical compositions as rocks from the Huatung Basin and yield an 40Ar/39Ar age of 135.0 ± 5.6 Ma, were removed from the overriding plate due to the excessive shear stress between the converging plates and were laterally transported by strike‐slip movement; alternatively, they were off‐scraped from the subducted Luzon forearc slices. The temporary uplift and collapse of the accretionary prism caused by seamount subduction may have been responsible for the genesis of the lenticular Shihmen Conglomerate.

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Section: Effects Of Alteration and Metamorphism On Element Mobilitymentioning

confidence: 99%

Geochemistry and Geochronology of the Accreted Mafic Rocks From the Hengchun Peninsula, Southern Taiwan: Origin and Tectonic Implications

et al. 2019

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“…Mafic volcanic rocks are closely associated and interbedded with radiolarian chert and occasionally with carbonates. Well‐preserved basaltic flows exhibiting pillow structures are also observed (Singh et al ; Khogenkumar et al , ). At places, podiform chromitites are exposed predominantly in the southern part of the NMO, associated with peridotites.…”

Section: Geology Of the Studied Areamentioning

confidence: 99%

Genesis and tectonic implications of cumulate pyroxenites and tectonite peridotites from the Nagaland–Manipur ophiolites, Northeast India: constraints from mineralogical and geochemical characteristics

et al. 2016

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The Nagaland–Manipur ophiolites (NMO) of Northeast India forms a part of the Tethyan ophiolites and comprises a suite of tectonite peridotites and cumulate mafic–ultramafic sequence with mafic extrusive–intrusive rocks, felsic intrusives and oceanic pelagic sediments along with minor podiform chromitites. However, sheeted dykes, which are considered as a significant component of ophiolites, are absent in the NMO. The tectonite peridotites are distinguished from the cumulate pyroxenites by the presence of pyroxene lineation, deformed bands and strained extinction in olivine, kink twin lamellae in pyroxene. Both the tectonite peridotites and cumulate pyroxenites contain aluminous spinel with Cr number [Cr# = Cr/(Cr + Al)] in the range of 0.14 to 0.29 and 0.27 to 0.48, respectively. Mg number [Mg# = Mg/(Mg + Fe2+)] in Cr‐spinel is higher in tectonite peridotites (0.71–0.76) than cumulate pyroxenites (0.44–0.53). Chondrite‐normalized rare earth elements (REE) patterns of cumulate pyroxenites exhibit depleted at light REEE (LREE) (LaN/SmN = 0.380–0.759) but flat middle REE (MREE) to heavy REE (HREE) (SmN/YbN = 0.622–0.756). However, the tectonite peridotites show gradual decrease in concentrations from HREE to MREE (SmN/YbN = 0.285–0.460) and slight increase in LREE (LaN/SmN = 0.721–2.201). The cumulate pyroxenites show strong enriched PPGE patterns and higher PGE concentrations (∑PGE = 85.8–163.5 ppb) compared with the tectonite peridotites (∑PGE = 34.8–113.0 ppb). The estimated equilibration temperature ranges from 890 to 931 °C for cumulate pyroxenites and 971 to 1156 °C for tectonite peridotites. The olivine–spinel equilibrium along with Cr‐spinel chemistry and PGE data suggests that the tectonite peridotites represent the residual mantle left after limited extraction of basaltic melts by low‐degree partial melting (<15%). Conversely, the presence of highly magnesian orthopyroxene and clinopyroxene in the cumulate pyroxenites in conjunction with their geothermometry suggests that they were formed at high pressure and temperature by magmatic fractionation from the basaltic melt. The geochemical data together with field and petrographical evidences indicate that both the tectonite peridotites and cumulate pyroxenites are essentially spinel‐bearing and devoid of plagioclase, suggesting their derivation in the mantle beyond the stability limit of plagioclase in a mid‐oceanic ridge tectonic setting. We conclude that the ultramafic sequence of the NMO was initially generated at a mid‐oceanic ridge tectonic setting close to the eastern boundary of the Indian passive margin and then thrust over the continental margin of the Indian Plate towards the west during its collisional and subduction process with/beneath the Myanmar Plate. Copyright © 2016 John Wiley & Sons, Ltd.

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“…However, their origin and tectonic setting are still debated. The existing tectonic models include (1) an island-arc origin (Bhattacharjee, 1991); (2) a mid-oceanic ridge origin (Singh, 2013;Khogenkumar et al, 2016); and (3) a mid-oceanic ridge-generated oceanic lithosphere, that underwent high-pressure metamorphism and deformation in a subduction channel and then was incorporated into an accretionary prism in the upper plate (Fareeduddin and Dilek, 2015). Most of the previous studies in the Indo-Myanmar ophiolites and these existing tectonic models for their evolution are almost entirely based on the geochemistry and geochronology of www.gsapubs.org | Volume 10 | Number 1 | LITHOSPHERE crustal rocks.…”

Section: Introductionmentioning

confidence: 99%

Mineralogy, geochemistry, and melt evolution of the Kalaymyo peridotite massif in the Indo-Myanmar Ranges (western Myanmar), and tectonic implications

et al. 2017

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We present new whole-rock major, trace, and platinum group element (PGE) and mineral chemistry data from the Kalaymyo peridotite massif in the central part of the Indo-Myanmar Ranges (western Myanmar) and discuss its mantle melt evolution. The Kalaymyo peridotites consist mainly of harzburgites, which show typical porphyroclastic or coarse-grained equigranular textures. They are composed of olivine (forsterite,

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Coexistence of MORB and OIB-type mafic volcanics in the Manipur Ophiolite Complex, Indo-Myanmar Orogenic Belt, northeast India: Implication for heterogeneous mantle source at the spreading zone

Cited by 47 publications

References 71 publications

Geochemistry and Geochronology of the Accreted Mafic Rocks From the Hengchun Peninsula, Southern Taiwan: Origin and Tectonic Implications

Geochemistry and Geochronology of the Accreted Mafic Rocks From the Hengchun Peninsula, Southern Taiwan: Origin and Tectonic Implications

Genesis and tectonic implications of cumulate pyroxenites and tectonite peridotites from the Nagaland–Manipur ophiolites, Northeast India: constraints from mineralogical and geochemical characteristics

Mineralogy, geochemistry, and melt evolution of the Kalaymyo peridotite massif in the Indo-Myanmar Ranges (western Myanmar), and tectonic implications

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