The Late Paleozoic Ocean-continent Transformation And Darabut Fault Evolution History Of The Western Junggar

The Western Junggar is a NE-SW block between the Eerqisi and Tianshan fault system,which is the Paleozoic accretion belt on account of the Junggar block subducting under kazakhstan plate.This study gets to know the late Paleozoic tectonic environment through research granites,rhyolite and darabut fault.Through granites zircon U-Pb dating,geochemistry and isotope geochemistry study,and rhyolites zircon U-Pb dating,geochemistry study,and analyze the Darlabut fault geometry property and kinematics characteristics.we get the following conclusion:(1)the Western Junggar region exists hercynian period and late hercynian magmatismBaogutu ??? and K956 rock mass in the southeastern of Darabut and Jiaman.Laomaduan I and Bieluagaxi rock mass in the northwest of Mayile have the characterisitics of adakite.Their zircon dating is for 309-309Ma.These rock mass may be products of plate subduction environment.The Western Junggar is in mid-ocean ridge subduction tectonic environment.Miaoergou?Akebasitao?Hatu?Kulumusu?Saikuke?Karamay?Hongshan?Laomaduan and Kangde rock mass belong to post-orogenic granites.They are the products of post-orogenic,within 299?316 Ma.The Western Junggar is in the post-orogenic environment after ridge subduetion of Paleo-Asian Ocean plate from late carboniferous to early Permian.(2)The Western Junggar is in ocean-continent transition environment for the later Carboniferous-early PermianPrismatic joints rhyolites general develop in the ocean-continent transition environment.Prismatic joints rhyolites of 294?310Ma confirme the existence with genetic relationship with Miaoergou rock mass.Rich alkaline magmatism and the formation of the large granite batholith in the orogenic stretch environment after the late Carboniferous put an end to the ocean-continent transition environment,and the Western Junggar entry stage of the Permian molasse formation.(3)Darabut fault continuous active from late Carboniferous to the CenozoicDarabut fault develops from the deep ductile shear zone,left-lateral slip and northwest wall decline.Darabut fault controls the distribution of the late Carboniferous sedimentary rocks and the Permian conglomerate sedimentation.Meanwhile Darabut fault shapes distribution location of rock mass.Darabut fault continuous active to Cenozoic and have the overall strike-slip displacement about 62?83.5 km.