Spinel compositions and tectonic relevance of the Bibong ultramafic bodies in the Hongseong collision belt, South Korea

Oh, Chang Whan; Rajesh, V.J.; Seo, Jung-Kil; Choi, Sung‐Gil; Lee, J.H.

doi:10.1016/j.lithos.2010.02.015

Cited by 27 publications

(10 citation statements)

References 52 publications

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“…그러나 마그마에 의해 매우 빠른 속도로 지표로 이동하기 때문에 저온저압 환경에서의 재평형 정도가 조산대 페리도타이트 암괴에 비해 미약하다는 장점을 가지고 있다. 우리나라의 경우, 초염기성 암괴(ultramafic massif) 가 홍성일대, 안동, 울산 등지에서 소규모 렌즈상(약 1 km 길이)으로 산출되나, 대개 상당한 정도의 사문 암화 작용과 이차 변성작용을 겪은 것으로 보고되었 다 (Oh et al, 2010, Kim et al, 2011. 맨틀 포획 암의 경우는 백령도, 간성일대, 아산-평택지역, 보은 및 제주도 등지에서 신생대 후기 알칼리현무암류내에 포획되어 있다 (김윤규 외, 1988;윤성효 외, 1998;신 홍자 외, 2006;양경희 외, 2009;Lee, 1996;Arai et al, 2001;Kil, 2006;Lee and Walker, 2006) (Fig.…”

Section: Al 1999) 판구조운동은 섭입과정을 통하여 해양지각 하부의 암석권 맨틀을 연약권으로 재순환시킨다unclassified

Lithospheric Mantle beneath the Korean Peninsula: Implications from Peridotite Xenoliths in Alkali Basalts

Choi¹

2012

The Journal of the Petrological Society of Korea

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Peridotite xenoliths hosted by alkali basalts from South Korea occur in Baengnyeong Island, Jeju Island, Boeun, Asan, Pyeongtaek and Ganseong areas. K-Ar whole-rock ages of the basaltic rocks range from 0.1 to 18.9 Ma. The peridotites are dominantly lherzolites and magnesian harzburgites, and the constituent minerals are Fo-rich olivine (Fo 88.4-92.0 ), En-rich orthopyroxene, Di-rich clinopyroxene, and Crrich spinel (Cr# = 7.8-53.6). Hydrous minerals, such as pargasite and phlogopite, or garnet have not been reported yet. The Korean peridotites are residues after variable degree of partial melting (up to 26%) and melt extraction from fertile MORB mantle. However, some samples (usually refractory harzburgites) exhibit metasomatic enrichment of the highly incompatible elements, such as LREE. Equilibration temperatures estimated using two-pyroxene geothermometry range from ca. 850 to 1050 o C. Sr and Nd isotopic compositions in clinopyroxene separates from the Korean peridotites show trends between depleted MORB-like mantle (DMM) and bulk silicate earth (BSE), which can be explained by secondary metasomatic overprinting of a precursor time-integrated depleted mantle. The Korean peridotite clinopyroxenes define mixing trends between DMM and EM2 end members on Sr-Pb and Nd-Pb isotopic correlation diagrams, without any corresponding changes in the basement. This is contrary to what we

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Section: Al 1999) 판구조운동은 섭입과정을 통하여 해양지각 하부의 암석권 맨틀을 연약권으로 재순환시킨다unclassified

Lithospheric Mantle beneath the Korean Peninsula: Implications from Peridotite Xenoliths in Alkali Basalts

Choi¹

2012

The Journal of the Petrological Society of Korea

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“…The composition of Cr‐spinel in peridotites reflects magma chemistry, degree of partial melting, fractional crystallization and variation in oxygen fugacity ( f O 2 ) (Dick and Bullen ; Barnes ; Kapsiotis ) or even the tectonic discrimination between mid‐ocean ridge and supra‐subduction zone settings (Dick and Bullen ; Arif and Jan ; Oh et al ; Singh ). It is also considered that Al content of Cr‐spinel is sensitive to mantle melting processes and that systematically decreases with the degree of peridotites depletion (Zhou et al , ; Uysal et al ).…”

Section: Petrogenesis and Tectonic Implicationsmentioning

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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“…They display a wide range of compositions reflecting their primary magmatic or secondary origin (Barnes and Roeder, 2001;Ghosh et al, 2013). Primary spinel can be well maintained during serpentinisation, hence unaltered spinels in serpentinite can be used as a petrogenetic and geotectonic indicator because their chemical composition depends on the petrogenesis and physical conditions of the host peridotites (Zhou et al, 1994;Karipi et al, 2007;Oh et al, 2010). The prime purpose of this paper is to present new data on the chemical variability of spinel-group minerals occurring in serpentinised peridotites from the Veria-Naousa ophiolite, north Greece, aiming also to unravel the petrogenetic processes during their formation.…”

Section: Introductionmentioning

confidence: 99%

Petrogenetic Significance of Spinels From Serpentinised Peridotites From the Verianaousa Ophiolite

Ρογκάλα¹,

Petrounias²,

Tsikouras³

et al. 2017

geosociety

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The Veria-Naousa ophiolitic complex represents a dismembered ophiolite unit, which is superimposed on a basement consisting of rocks belonging to the Pelagonian and Axios (Almopias subzone) isopic zones in northern Greece. Mantle peridotites are composed of variably serpentinised lherzolite and harzburgite intruded by a sparse network of pyroxenitic dykes. The serpentinised lherzolite and harzburgite contain , ,

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Spinel compositions and tectonic relevance of the Bibong ultramafic bodies in the Hongseong collision belt, South Korea

Cited by 27 publications

References 52 publications

Lithospheric Mantle beneath the Korean Peninsula: Implications from Peridotite Xenoliths in Alkali Basalts

Lithospheric Mantle beneath the Korean Peninsula: Implications from Peridotite Xenoliths in Alkali Basalts

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

Petrogenetic Significance of Spinels From Serpentinised Peridotites From the Verianaousa Ophiolite

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