Eocene high grade metamorphism and crustal anatexis in the North Himalaya Gneiss Domes, Southern Tibet

Gao, Li-E; Zeng, Lingsen; Xie, Kui

doi:10.1007/s11434-011-4805-4

Cited by 35 publications

(22 citation statements)

References 69 publications

(101 reference statements)

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“…Locations of samples for zircon U -Pb dating are also shown. Zircon U-Pb age of 44.1 + 1.2 Ma for the Dala pluton is from Aikman et al (2008) and Qi et al (2008); the others are from Zeng et al (2011Zeng et al ( , 2012b and Gao et al (2012). LH, Lower Similar magmatic events in terms of timing and geochemical nature were also reported by Liu (2013) from the Ramba gneiss dome.…”

Section: Eocene Magmatism In the Tethyan Himalaya Southern Tibetsupporting

confidence: 67%

“…1), documented that the NHGD has preserved records on episodic crustal anatexis before c. 35 Ma (Aikman et al 2008;Qi et al 2008;Zeng et al 2009Zeng et al , 2011Gao et al 2012;Hou et al 2012). A systematic and detailed geochemical and isotopic (Sr and Nd) study has demonstrated that these granites, especially the Mid-Eocene two-mica granites (TMGs), are characterized by high CaO and high Na/K and Sr/Y ratios, and might represent partial melting of dominantly garnet amphibolites under thickened crustal conditions (Zeng et al 2011;Hou et al 2012).…”

Section: Eocene Magmatism In the Tethyan Himalaya Southern Tibetmentioning

confidence: 99%

“…These rocks generally do not show evidence of metamorphism. In the YGD area, the metamorphic rocks underlying the Tethyan sedimentary sequence consist of augen gneiss, garnet-bearing metapelite, garnet-graphite schist, amphibolite with subordinated epidotite, and pyroxenite (Zhang et al 2007;Zeng et al 2009;Gao et al 2012), which is broadly similar in mineral assemblages to those gneiss domes to the west. From the core to the margin of the YGD, it consists of Cenozoic granites in the core showing a semi-circular shape on the map, high-grade augen gneiss, garnet biotite gneiss, garnet amphibolite, and garnet-graphite schist toward the margin, followed by the overlying Tethyan sedimentary rocks (Fig.…”

Section: Geological Setting and Sample Descriptionsmentioning

confidence: 99%

“…These granitic dykes formed at 35.3 + 1.1 Ma (zircon sensitive high-resolution ion microprobe (SHRIMP) U -Pb age) ) and intruded the high-grade metamorphic rocks and the TMGs. In contrast, TMGs occur either as large plutons or as sills and intruded the granulite facies metapelite, marble, augen gneiss, and garnet amphibolite (Zhang et al 2007;Aikman et al 2008Aikman et al , 2012aQi et al 2008;Zeng et al 2009Zeng et al , 2011Gao et al 2012;Hou et al 2012). Occasionally, these granites also contain small enclaves of garnet biotite gneiss and andesitic composition (Zeng et al 2011).…”

Section: Geological Setting and Sample Descriptionsmentioning

confidence: 99%

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Eocene magmatism in the Tethyan Himalaya, southern Tibet

Zeng

Gao

Tang

et al. 2014

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Recent studies in the Yardoi gneiss dome of the Tethyan Himalaya, southern Tibet demonstrated that the Himalayan orogenic belt experienced a major episode of crustal melting in the Mid-Eocene (c. 44–40 Ma), represented by the genesis of a suite of high Sr/Y two-mica granites (TMGs) accompanied by leucogranites. Geochemical and U–Pb age data indicate that (1) both the leucogranite and the porphyritic leucogranite formed at c. 44–41 Ma are characterized by similar Sr–Nd–Hf isotope systematics to those in the less evolved TMGs; (2) these three suites of rocks might represent a Mid-Eocene igneous complex derived from partial melting of amphibolite under crustal thickened conditions; and (3) in contrast with the TMGs, leucogranites experienced hydrothermal-magma interactions as well as plagioclase fractional crystallization as revealed from pronounced negative Eu anomalies, much lower Sr concentrations, and elevated common Pb and U concentrations in the latest magmatic zircon overgrowth. Our data suggest that magmatic differentiation of more primitive magmas could have played a critical role in the generation of leucogranites. Documentation of partial melting of deep crustal rocks during the earliest phase of the tectonic evolution of the Himalayan orogen implies that the large-scale collisional orogenic belt could experience intensive partial melting under contraction and thickening conditions, which could profoundly affect the geophysical and geochemical properties as well as rheological properties and facilitate the initiation of movement or flow of deep crustal rocks.

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Section: Eocene Magmatism In the Tethyan Himalaya Southern Tibetsupporting

confidence: 67%

Section: Eocene Magmatism In the Tethyan Himalaya Southern Tibetmentioning

confidence: 99%

Section: Geological Setting and Sample Descriptionsmentioning

confidence: 99%

Section: Geological Setting and Sample Descriptionsmentioning

confidence: 99%

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Eocene magmatism in the Tethyan Himalaya, southern Tibet

Zeng

Gao

Tang

et al. 2014

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“…Granites, migmatites, and high-grade metamorphic rocks are important components within these two belts and record distinct types of metamorphism and partial melting reactions of middle-lower crustal materials in response to the tectonic evolution of the Himalayan orogen [1,4,8,13,14,16,[26][27][28][29]. NHGD within the Tethyan Himalaya consists of a series of semi-continuous oval shape gneiss dome.…”

Section: Geological Setting and Sample Descriptionsmentioning

confidence: 99%

Episodic crustal anatexis and the formation of Paiku composite leucogranitic pluton in the Malashan Gneiss Dome, Southern Tibet

et al. 2013

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The Paiku composite leucogranitic pluton in the Malashan gneiss dome within the Tethyan Himalaya consists of tourmaline leucogranite, two-mica granite and garnet-bearing leucogranite. Zircon U-Pb dating yields that (1) tourmaline leucogranite formed at 28.2±0.5 Ma and its source rock experienced simultaneous metamorphism and anatexis at 33.6±0.6 Ma; (2) two-mica granite formed at 19.8±0.5 Ma; (3) both types of leucogranite contain inherited zircon grains with an age peak at ~480 Ma. These leucogranites show distinct geochemistry in major and trace elements as well as in Sr-Nd-Hf isotope compositions. As compared to the two-mica granites, the tourmaline ones have higher initial Sr and zircon Hf isotope compositions, indicating that they were derived from different source rocks combined with different melting reactions. Combined with available literature data, it is suggested that anatexis at ~35 Ma along the Himalayan orogenic belt might have triggered the initial movement of the Southern Tibetan Detachment System (STDS), and led to the tectonic transition from compressive shortening to extension. Such a tectonic transition could be a dominant factor that initiates large scale decompressional melting of fertile high-grade metapelites along the Himalayan orogenic belt. Crustal anatexis at ~28 Ma and ~20 Ma represent large-scale melting reactions associated with the movement of the STDS.Himalayan orogenic belt, Northern Himalayan Gneiss Domes, leucogranite, crustal anatexis, tectonic transition Citation:Gao L E, Zeng L S, Hou K J, et al. Episodic crustal anatexis and the formation of Paiku composite leucogranitic pluton in the Malashan Gneiss Dome, Southern Tibet.

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Cambrian magmatism in the Tethys Himalaya and implications for the evolution of the Proto‐Tethys along the northern Gondwana margin: A case study and overview

Zhang

Santosh

et al. 2018

Geological Journal

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The Cuonadong Dome in southern Tibet is a newly discovered gneiss dome in the Tethys Himalaya. Here, we investigate the Late Cambrian augen gneiss (orthogneiss) within the core of this dome to address the controversy surrounding early Palaeozoic tectonic evolution of the northern margin of eastern Gondwana. We report new zircon laser ablation multicollector inductively coupled plasma mass spectrometry (LA‐(MC‐)ICP‐MS) U‐Pb ages, Lu‐Hf isotopes, whole‐rock major and trace element geochemistry, and Sr‐Nd‐Pb data on representative samples from the granitic gneiss. The weighted mean of 116 analyses of zircon grains yields an age of 498.2 ± 1.5 Ma (mean square weighted deviation [MSWD] = 1.2). Forty‐one spots analyses on these grains show consistent εHf (t) values of −2 to +4 (average = +1.1), corresponding to Hf crustal model age (TDM2) of 1.3 to 1.6 Ga (average = 1.39 Ga). The orthogneiss (metagranite) is characterized by high Si and K contents, with low Al, Mg, and Ti, and A/CNK values ranging from 0.87 to 0.98 with an average of 0.92, indicating a metaluminous composition and I‐type granitoid affinity. The granitoid displays significant enrichment in light rare earth elements (LREEs) and relatively flat high rare earth element (HREE) patterns, with strong negative Eu anomalies (Eu/Eu* = 0.26–0.31). The primitive mantle‐normalized trace elements show a relative enrichment in large‐ion lithophile elements, such as Rb, and high‐field strength elements, such as Th, U, Zr, and Hf, with depletion in Ba, Nb, Ta, Sr, P, and Ti. The rocks show high initial 87Sr/86Sr ratios (0.7221–0.7248) and low εNd (t) values (−8.9 to −7.3) with Nd model ages (TDM) of 1.79–1.91 Ga. Their radiogenic Pb isotopic compositions show (206Pb/204Pb)t = 18.804–19.110, (207Pb/204Pb)t = 15.730–15.768, and (208Pb/204Pb)t = 38.409–39.054, indicating an ancient upper middle continental crustal origin. Our study shows that the protolith of the metagranite was most likely derived from the partial melting of upper continental crust with a minor contribution of depleted mantle materials. Through integration of the regional information on early Palaeozoic magmatism and metamorphic events, we contend that the protolith of the Cuonadong granitic gneiss formed in an accretionary setting associated with the early Palaeozoic Proto‐Tethys Oceanic plate subduction beneath the Gondwana continent.

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Eocene high grade metamorphism and crustal anatexis in the North Himalaya Gneiss Domes, Southern Tibet

Cited by 35 publications

References 69 publications

Eocene magmatism in the Tethyan Himalaya, southern Tibet

Eocene magmatism in the Tethyan Himalaya, southern Tibet

Episodic crustal anatexis and the formation of Paiku composite leucogranitic pluton in the Malashan Gneiss Dome, Southern Tibet

Cambrian magmatism in the Tethys Himalaya and implications for the evolution of the Proto‐Tethys along the northern Gondwana margin: A case study and overview

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