Relicts of the Early Cretaceous seamounts in the central-western Yarlung Zangbo Suture Zone, southern Tibet

Dai, Jingen; Wang, Chengshan; Li, Yalin

doi:10.1016/j.jseaes.2011.12.024

Cited by 65 publications

(17 citation statements)

References 82 publications

(226 reference statements)

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“…(1) Generation of the chromitites in an SSZ environment at c. 375 Ma (McGowan et al, 2015; Fig. 8c); subduction may have followed within 10-40 Myr, the typical life of such systems (Dai et al, 2012). Similar ages (364-373 Ma) have been reported for gabbros from the Dangxiong and Najiu ophiolites (Dai et al, 2011), and from the Iranian sector of the extended suture (Moghadam et al, 2015), and have been taken as evidence of a relationship to subduction within the Paleo-Tethys ocean.…”

Section: Summary Of Timing Of Eventsmentioning

confidence: 99%

“…This model also resolves some apparent conflicts in the geology and petrology of the YZSZ ophiolites. For example, the mafic rocks 'associated' (tectonically juxtaposed) with the YZSZ peridotites are Jurassic-Cretaceous in age and mainly have MORB affinities (Zhou et al, 2002;Zhong et al, 2006;Zhang et al, 2005; other references have been given by Dai et al, 2012Dai et al, , 2013. This is not easily reconciled with the petrology of the ultramafic rocks, which show a two-stage evolution with extreme depletion overprinted by an SSZ trace element signature (including the chromitites; Zhou et al, 1996Zhou et al, , 2005Zhou et al, , 2014.…”

Section: Geological Implicationsmentioning

confidence: 99%

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Mantle Recycling: Transition Zone Metamorphism of Tibetan Ophiolitic Peridotites and its Tectonic Implications

et al. 2016

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Large peridotite massifs are scattered along the 1500 km length of the Yarlung-Zangbo Suture Zone (southern Tibet, China), the major suture between Asia and Greater India. Diamonds occur in the peridotites and chromitites of several massifs, together with an extensive suite of trace phases that indicate extremely low fO 2 (SiC, nitrides, carbides, native elements) and/or ultrahigh pressures (UHP) (diamond, TiO 2 II, coesite, possible stishovite). New physical and isotopic (C, N) studies of the diamonds indicate that they are natural, crystallized in a disequilibrium, high-T environment, and spent only a short time at mantle temperatures before exhumation and cooling. These constraints are difficult to reconcile with previous models for the history of the diamond-bearing rocks. Possible evidence for metamorphism in or near the upper part of the Transition Zone includes the following: (1) chromite (in disseminated, nodular and massive chromitites) containing exsolved pyroxenes and coesite, suggesting inversion from a high-P polymorph of chromite; (2) microstructural studies suggesting that the chromitites recrystallized from fine-grained, highly deformed mixtures of wadsleyite and an octahedral polymorph of chromite; (3) a new cubic Mg-silicate, with the space group of ringwoodite but an inverse-spinel structure (all Si in octahedral coordination); (4) harzburgites with coarsely vermicular symplectites of opx þ Cr-Al spinel 6 cpx; reconstructions suggest that these are the breakdown products of majoritic garnets, with estimated minimum pressures to > 13 GPa. Evidence for a shallow pre-metamorphic origin for the chromitites and peridotites includes the following: (1) trace-element data showing that the chromitites are typical of suprasubduction-zone (SSZ) chromitites formed by magma mixing or mingling, consistent with Hf-isotope data from magmatic (375 Ma) zircons in the chromitites; (2) the composition of the new cubic Mg-silicate, which suggests a low-P origin as antigorite, subsequently dehydrated; (3) the peridotites themselves, which carry the trace element signature of metasomatism in an SSZ environment, a signature that must have been imposed before the incorporation of the UHP and low-fO 2 phases. A proposed P-T-t path involves the original formation of chromitites in mantle-wedge

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Section: Summary Of Timing Of Eventsmentioning

confidence: 99%

Section: Geological Implicationsmentioning

confidence: 99%

Mantle Recycling: Transition Zone Metamorphism of Tibetan Ophiolitic Peridotites and its Tectonic Implications

et al. 2016

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“…2). Recent geochronological and biostratigraphic studies in these ophiolites have revealed crystallization, deposition and metamorphic ages ranging from the middle Jurassic to the early Cretaceous; however, most of the igneous ages of the ophiolites are clustered at 130-120 Ma (Table 1; McDermid et al, 2002;Zhou, 2002;Malpas et al, 2003;Miller et al, 2003;Ziabrev et al, 2003;Wang et al, 2006;Wei et al, 2006a, b;Zhong et al, 2006;Chan et al, 2007;Guilmette et al, 2008Guilmette et al, , 2009Li et al, 2008Li et al, , 2009Xia et al, 2008b;Dai et al, 2012). Petrological and geochemical studies of various crustal units (lavas, dikes, sills and gabbros) of the YZSZ ophiolites have indicated multi-stage melting episodes in different tectonic settings during their magmatic accretion and evolution, encompassing mid-ocean ridge, and backarc to forearc suprasubduction zone environments (Table 1; McDermid et al, 2002;Hébert et al, 2003;Xia et al, 2003;Dubois-Côté et al, 2005;Zhou et al, 2005;Bédard et al, 2009;Guilmette et al, 2008Guilmette et al, , 2009Geng et al, 2010;Dai et al, 2011a, b;Bezard et al, 2011;Liu et al, 2010Liu et al, , 2012Hébert et al, 2012;Dai et al, 2011bDai et al, , 2013Dilek and Furnes, 2014;Liu et al, 2015;Xu et al, 2015a).…”

Section: Yzsz Ophiolites and Associated Oib-type Rocksmentioning

confidence: 99%

OIB- and P-type ophiolites along the Yarlung- Zangbo Suture Zone (YZSZ), Southern Tibet: Poly- Phase melt history and mantle sources of the Neotethyan oceanic lithosphere

Yang¹,

Dilek²

2015

Episodes

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“…Abundant and mostly bioclastic-limestone blocks, probably detached from the outer peri-Gondwana shelf or seamounts within the Neo-Tethys Ocean (Shen et al, 2003a(Shen et al, , 2003b, yield Middle-Late Permian crinoids and bryozoans, together with foraminifera of Early Triassic, Early Jurassic, and Late Cretaceous age (Tapponnier et al, 1981;Jin et al, 2015, and references therein). Blocks derived from seamounts within the Neo-Tethys Ocean, as recorded by limestone and chert deposited directly on oceanic island basalt (OIB), have been reported in the Zhongba area (Dai et al, 2012). Blocks of radiolarian chert are of two types: A Middle-Upper Triassic group with continental-margin affinity, and an Upper Jurassic-Lower Cretaceous group with oceanic-basin affinity (Zhu et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Discovery of Upper Cretaceous Neo-Tethyan trench deposits in south Tibet (Luogangcuo Formation)

Garzanti

2018

Lithosphere

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Sedimentary basins within the Transhimalayan arc-trench system provide paleotectonic and paleogeographic information on the evolution of the late Mesozoic-early Cenozoic Neo-Tethyan subduction zone along the southern Asian margin. This paper presents detailed stratigraphic, sedimentologic, petrographic, detrital-zircon geochronologic and Hf isotopic data from the Luogangcuo Formation exposed as part of the Xiukang Mélange in south Tibet. The Luogangcuo Formation was deposited (ca. 88-81 Ma) in a trench environment on a deep-sea fan fed from the Lhasa block through a submarine canyon. Dominant chert and subordinate sandstone and limestone clasts in conglomerate beds indicate recycling from the Neo-Tethyan subduction complex during repeated episodes of gravitational failure. The interbedded turbiditic sandstones were sourced directly from the Gangdese magmatic arc and central Lhasa terrane. Detrital volumes from the active Asian margin increased markedly at ca. 88 Ma as a result of uplift of central Lhasa, leading to deltaic progradation, filling of the Xigaze forearc basin, and bypassing of sediments funneled via canyons across the subduction complex to reach the Luogangcuo trench basin at abyssal depths.

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Relicts of the Early Cretaceous seamounts in the central-western Yarlung Zangbo Suture Zone, southern Tibet

Cited by 65 publications

References 82 publications

Mantle Recycling: Transition Zone Metamorphism of Tibetan Ophiolitic Peridotites and its Tectonic Implications

Mantle Recycling: Transition Zone Metamorphism of Tibetan Ophiolitic Peridotites and its Tectonic Implications

OIB- and P-type ophiolites along the Yarlung- Zangbo Suture Zone (YZSZ), Southern Tibet: Poly- Phase melt history and mantle sources of the Neotethyan oceanic lithosphere

Discovery of Upper Cretaceous Neo-Tethyan trench deposits in south Tibet (Luogangcuo Formation)

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