Neoproterozoic magmatic and metamorphic imprints in the East Kunlun Orogenic Belt, North Tibetan Plateau, NW China: Implications for the assembly and initial breakup of the Rodinia supercontinent

Abstract

The East Kunlun Orogenic Belt (EKOB), located on the northern margin of the Tibetan Plateau, experienced intense, long-lasting,and complicatedmulti-stage orogeny from the Neoproterozoic to Early Mesozoic. Neoproterozoic magmatic and metamorphic events recorded critical information on Precambrian tectonic evolutionary history. Zircon U-Pb ages of 914 ± 6.5, 902 ± 5.3, and 856 ± 6.8 Ma were determined for granitic gneiss, monzogranite, and charnockite, respectively. Geochemical and petrological studies reveal high SiO2, Al2O3, and K2O content with abundant Al-rich minerals, such as garnet and muscovite, which show typical S-type granite properties. The εHf(t) values ranging from − 6.5 to + 5.6 (TDM2 = 1.4–2.2 Ga) indicate a primarily Paleoproterozoic metagreywackes and metapelitic derivation with mantle contribution. Zircon U-Pb results show that amphibolite yielded ages of 846 ± 5.2 Ma. Geochemistry andεHf(t) values ranging from 10.5 to 15.9 (TDM1 = 0.8–0.9 Ga) suggest that the mafic magma originated from depleted mantle metasomatized by subduction fluid. We propose that the Neoproterozoic rocks in this study were generated in syn-orogenesis and incipient continental rift-related extension environment, whichcorresponds to the assembly and initial breakup of the Rodinia supercontinent. In the EKOB, The initial breakup-related extension of the supercontinent affected by super plume occurred at ca. ~ 0.85 Ga. East Kunlun and its adjacent blocks were within a single tectonic domain and recorded important evolutionary history of the Rodinia supercontinent.