Remnants of a Cretaceous intra-oceanic subduction system within the Yarlung–Zangbo suture (southern Tibet)

Aitchison, Jonathan C.; Badengzhu,; Davis, Aileen M.; Liu, Jianbing B.; Luo, Hui; Malpas, John; McDermid, I; Wu, Hiyun; Ziabrev, S; Zhou, Mei‐Fu

doi:10.1016/s0012-821x(00)00287-9

Cited by 359 publications

(221 citation statements)

References 34 publications

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“…Changes in sedimentation patterns and the appearance of accretionary prism and arc material within Maastrichtian strata of the southern Tibetan Tethyan Himalaya have been attributed to onset of interaction between India and Asia at this time [e.g., Liu and Einsele, 1994;Shi and Yin, 1995;Liu and Einsele, 1996;Willems et al, 1996]. However, these changes in sedimentation may be equally well explained by southward obduction of Neo-Tethys intraoceanic rocks, including ophiolitic fragments and subduction-accretion complexes, onto the northern margin of India during Late Cretaceous-early Tertiary time prior to India-Asia collision Burg and Chen, 1984;Burg et al, 1987;Searle et al, 1987;Beck et al, 1996;Gnos et al, 1997;Makovsky et al, 1999;Aitchison et al, 2000]. Further questioning an early age for collision in southern Tibet is the lack of evidence for Asian-derived detritus or increased rates of tectonic subsidence in Paleocene -Eocene strata of the Tethyan Himalaya [Rowley, 1996[Rowley, , 1998Aitchison et al, 2000Aitchison et al, , 2002.…”

Section: Introductionmentioning

confidence: 99%

“…However, these changes in sedimentation may be equally well explained by southward obduction of Neo-Tethys intraoceanic rocks, including ophiolitic fragments and subduction-accretion complexes, onto the northern margin of India during Late Cretaceous-early Tertiary time prior to India-Asia collision Burg and Chen, 1984;Burg et al, 1987;Searle et al, 1987;Beck et al, 1996;Gnos et al, 1997;Makovsky et al, 1999;Aitchison et al, 2000]. Further questioning an early age for collision in southern Tibet is the lack of evidence for Asian-derived detritus or increased rates of tectonic subsidence in Paleocene -Eocene strata of the Tethyan Himalaya [Rowley, 1996[Rowley, , 1998Aitchison et al, 2000Aitchison et al, , 2002. This, together with recognition of an Indian promontory in Kashmir [e.g., Treloar and Coward, 1991], counterclockwise rotation of India [e.g., Patriat and Achache, 1984;Klootwijk et al, 1985;Dewey et al, 1989], and the lack of evidence for Paleocene to early Eocene high-pressure metamorphism within the central and eastern Himalaya, have contributed to the popular view that collision first began in the western Himalaya and subsequently propagated eastward [e.g., Rowley, 1996].…”

Section: Introductionmentioning

confidence: 99%

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Paleocene–Eocene record of ophiolite obduction and initial India‐Asia collision, south central Tibet

2005

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Uppermost Cretaceous to Eocene marine sedimentary sequences occur both to the south and north of the Yarlung Zangbo suture in south central Tibet. They consist of Indian‐margin strata of the northern Tethyan Himalaya and Asian‐margin strata of the Gangdese forearc. Both assemblages are characterized by major changes in depositional environment and sedimentary provenance at ∼65 Ma and an appearance of detrital chromium‐rich spinel of ophiolite affinity (TiO2 generally <0.1 wt%) during the Paleocene. Ophiolitic melange exposed along the suture could have provided a source for detrital spinel. The melange occurs in the hanging wall of a north dipping, south directed mylonitic shear zone which includes a tectonic sliver of mafic schist. Amphibole from the schist yields 40Ar/39Ar ages of ∼63 Ma, which we attribute to cooling during slip along the shear zone and southward obduction of the melange. Melange obduction was coeval with the development of an angular unconformity within the Gangdese forearc basin to the north (between late Maastrichtian time and ∼62 Ma). Upper Paleocene to middle Eocene sandstones in the northern Tethyan Himalaya yield 200–120 Ma U‐Pb detrital zircon ages and 190–170 Ma 40Ar/39Ar detrital mica ages. These detrital grains were most likely sourced from regions north of the Yarlung Zangbo suture, suggesting that onset of India‐Asia collision in south central Tibet is middle Eocene or older in age. Collectively, our results support previous suggestions that oceanic rocks were obducted onto the northern margin of India during latest Cretaceous–earliest Tertiary time. Coeval changes in Gangdese forearc sedimentation raise the possibility that this obduction event marks onset of tectonic interaction between India and Asia at ∼65 Ma. Alternatively, in concert with the conventional view of Eocene collision initiation, the obducted oceanic rocks may be of intraoceanic origin, while coeval changes in Gangdese forearc sedimentation may be a consequence of an increase in the rate of ocean‐continent convergence following the demise of the intraoceanic subduction zone.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Paleocene–Eocene record of ophiolite obduction and initial India‐Asia collision, south central Tibet

2005

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“…Tectonic setting Although it has been widely accepted that the southern Lhasa sub-block was in an arc setting related to the subduction of the Neo-Tethyan oceanic slab during the Jurassic-Cretaceous (Debon et al, 1986;Harris et al, 1990;Chung et al, 2005;Kapp et al, 2005;Pan et al, 2006;Decelles et al, 2007;Kapp et al, 2007;Wen et al, 2008a;Zhu et al, 2009;Kang et al, 2010;Zhang et al, 2010;Jiang et al, 2012;Zhu et al, 2012), details of the tectonic setting and nature of the southern Lhasa sub-block have recently been an issue of debate. Previous investigations have suggested either a Cretaceous intra-oceanic subduction system within the Indus-Yarlung Tsangpo Suture (Aitchison et al, 2000(Aitchison et al, , 2007 or a juvenile island arc block accreted to the Lhasa block during the Late Paleozoic (e.g., Ji et al, 2009a,b;Zhu et al, 2011).…”

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confidence: 99%

Late Cretaceous crustal growth in the Gangdese area, southern Tibet: Petrological and Sr–Nd–Hf–O isotopic evidence from Zhengga diorite–gabbro

et al. 2013

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“…The transition zone is massive dunite, several to hundreds of meters in thickness. The mantle sequence consists of clinopyroxene-bearing harzburgites (lherzolites) and harzburgites which contain dunite lenses and abundant pods of chromitites [6,7,41].…”

Section: Introductionmentioning

confidence: 99%

“…The chromitites were initially thought to have bearing on the formation and evolution of the ophiolite. The Luobusa ophiolite originated at a mid-ocean ridge spreading center at 177 ± 31 Ma and was later modified by supra-subduction zone (SSZ) magmatism at 120 ± 10 Ma involving an intra-oceanic subduction system [5][6][7]41,53,54]. However, the presence of ultrahigh-pressure (UHP) and highly reduced minerals such as diamond, coesite, and native elements, initially found in the chromitites but more recently also in their host peridotites, requires additional processes or models to outline the genesis of the chromitites (e.g., [4,10,11,13,[17][18][19][20][55][56][57]).…”

Section: Introductionmentioning

confidence: 99%

Timing of Secondary Hydrothermal Alteration of the Luobusa Chromitites Constrained by Ar/Ar Dating of Chrome Chlorites

Guo

et al. 2018

Minerals

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Chrome chlorites are usually found as secondary phases formed by hydrothermal alteration of chromite deposits and associated mafic/ultramafic rocks. Here, we report the 40 Ar/ 39 Ar age of chrome chlorites separated from the Luobusa massive chromitites which have undergone secondary alteration by CO 2 -rich hydrothermal fluids. The dating results reveal that the intermediate heating steps (from 4 to 10) of sample L7 generate an age plateau of 29.88 ± 0.42 Ma (MSWD = 0.12, plateau 39 Ar = 74.6%), and the plateau data points define a concordant inverse isochron age of 30.15 ± 1.05 Ma (MSWD = 0.08, initial 40 Ar/ 36 Ar = 295.8 ± 9.7). The Ar release pattern shows no evidence of later degassing or inherited radiogenic component indicated by an atmospheric intercept, thus representing the age of the hydrothermal activity. Based on the agreement of this hydrothermal age with the~30 Ma adakitic plutons exposed in nearby regions (the Zedong area, tens of kilometers west Luobusa) and the extensive late Oligocene plutonism distributed along the southeastern Gangdese magmatic belt, it is suggested that the hydrothermal fluids are likely related to the~30 Ma magmatism. The hydrothermal fluid circulation could be launched either by remote plutons (such as the Sangri granodiorite, the nearest~30 Ma pluton west Luobusa) or by a similar coeval pluton in the local Luobusa area (inferred, not found or reported so far). Our results provide important clues for when the listwanites in Luobusa were formed.

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Remnants of a Cretaceous intra-oceanic subduction system within the Yarlung–Zangbo suture (southern Tibet)

Cited by 359 publications

References 34 publications

Paleocene–Eocene record of ophiolite obduction and initial India‐Asia collision, south central Tibet

Paleocene–Eocene record of ophiolite obduction and initial India‐Asia collision, south central Tibet

Late Cretaceous crustal growth in the Gangdese area, southern Tibet: Petrological and Sr–Nd–Hf–O isotopic evidence from Zhengga diorite–gabbro

Timing of Secondary Hydrothermal Alteration of the Luobusa Chromitites Constrained by Ar/Ar Dating of Chrome Chlorites

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