The Tarim Craton, one of the main three continental blocks(plates)in China, located in the center of Asia, was involved in the assembly and break-up of the Rodinia supercontinent during the Neoproterozoic. However, its tectonic evolution during these events remains more controversial. In this paper, petrology, geochemistry, zircon U-Pb age and Hf isotopic data for rhyolite and associated syenogranite were researched in Nanhua strata in the Quruqtagh block, northern Tarim Craton. The results show the uniformity in emplacement time, space and source materials for granitic volcanic-intrusive complexes. Zircon U-Pb dating results give an emplacement age of 735±10 Ma for the syenogranite and 738.9±5.4 Ma for the rhyolite. They are the same products of magma in Nanhua Neoproterozoic. The granitic volcanic-intrusive complexes are characterized by higher SiO2(69.85%~73.87%) contents, lower Fe(2.36%~2.96%)contents, depletion in Mg(0.16%~0.75%), enrichment in alkali(Na2O+K2O=7.51%~9.05%), belonging to alkaline series and weakly peraluminous rocks. The geochemistry of the race elements suggests the enrichment large ion lithophile elements(K, Rb and Th) and light rare earth elements(LREEs), depletion in Nb, Ta, Ba, Sr, P and Ti, which indicate the characteristics of A2-subtype granite, and belonging to the decompression and extension setting. Zircon Hf isotopic data indicates that εHf(t)values are all negative and varying in the range of-17.4~-10.6, two-stage model ages(TDM2) range from 2732~2321 Ma, and we propose that the rocks were most likely produced by partial melting of crystalline basement during Archean-Proterozoic which may have been derived from mantle magmas. In combination with the results of previous studies, we argue that the study area, the Quruqtagh block, northern Tarim Craton, began to entered the decompression and extension setting in 735 Ma, after that, the break-up of the Rodinia supercontinent has occurred.
. Genesis and geological significances of Nanhua granitic volcanic-intrusive complexes in Quruqtagh on the northern margin of the Tarim block, China[J]. Chinese Journal of Geology, 2016, 51(1): 239-261.