Growth of early Paleozoic continental crust linked to the Proto-Tethys subduction and continental collision in the East Kunlun Orogen, northern Tibetan Plateau
نویسندگان
چکیده
The East Kunlun Orogen (EKO) in the northern Tibetan Plateau records two continental collisional orogenic events and magmatism early Paleozoic Mesozoic. However, possible magmatic additions to crust growth of EKO different tectonic stages orogeny have been overlooked. Three phases plutons from Xiangride-Kuhai area east chosen for detailed investigation results are reported here. oldest suite (Stage 1) includes ca. 471 Ma Qurelong Monzodiorite 454 granodiorite Zhiyu Intrusive Complex. monzodiorite has a sanukitoid-like composition with high TiO2 Y contents is interpreted as being derived partial melting metasomatized mantle wedge lherzolite. typified by its SiO2 content, Sr/Y ratio, depleted Hf isotope, an adakite-like melt subducted Proto-Tethys oceanic crust. can be linked northward subduction Ocean between 520 450 Ma. Stage 2 represented plutonic emplaced during 450−431 I-type granitic composition. Of these, 447 Kengdenongshe Intrusion composed peraluminous granite enriched Nd-Hf isotopes indicative Mesoproterozoic igneous source orogen. 450−434 monzogranite Walega intrusive complexes exhibit variable element isotope compositions. They would generated magma mixing felsic melts old mafic magmas lithospheric mantle, proportion >30%. 431 quartz diorite Complex formed through crustal assimilation fractional crystallization >60%. was closure branches subsequent collision 450−426 Magmatism diminished 426 410 exhumation lithosphere indicated presence retrograde eclogites EKO. 3 408 Langmuri 403 Niantang Syenogranite. These or A-type isotopes. might remelting juvenile post-collisional extensional setting 410−390 Identification melts, stage 1 plutons, show that subcrustal materials significantly transferred overlying Hence 2) settings contributes 3) dominated reworking pre-existing processes previous view which orogens no growth, inconsistent proposal significant only setting.
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ژورنال
عنوان ژورنال: Geological Society of America Bulletin
سال: 2022
ISSN: ['1943-2674', '0016-7606']
DOI: https://doi.org/10.1130/b36292.1