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Title:: Tectonic Setting and Geochemical Characteristics of Different Kinds of Volcanic Rocks from Bayingou Ophiolitic Melange Belt, Xinjiang

Author(s):: SI Guo-hui; SU Hui-ping; LI Wei-na; LI De-cheng; ZHANG Chao; Xi’an Institute of Geological and Mineral Exploration, Xi’an 710100, Shaanxi, China

Keywords:: geochemistry; ophiolitic melange; basalt; Late Paleozoic; tectonic setting; North Tianshan; Xinjiang

Abstract:: Late Paleozoic ophiolitic melange belt in North Tianshan, which locates in the north rim fault zone of Middle Tianshan, spreads in NWW-SEE direction. Bayingou ophiolitic melange is an important part and the typical representative of the belt. Based on the previous researches, the material composition of Bayingou ophiolitic melange belt was analyzed by the field geological mapping and section measuring. The results show that there are at least three kinds of basaltic rocks, including basaltic rock associated with metaperidotite and gabbro, basaltic rock associated with pyroclastic and acidic volcanic rocks, and basaltic rock in the margin of ophiolitic melange; the basaltic rocks correspond to MORB, OIB and CRB types of basalts, reflecting the complexity of formation and evolution of Bayingou ophiolitic melange belt. The comparison of geological bodies in the both sides of Bayingou ophiolitic melange belt shows that Bayingou ocean closes at the end of Early Carboniferous.