Ju Force Tectonic Melange Geological Features And Kinetic Studies

During the process of the regional geological survey project of land and resources in Midu, Xiangyun, Weishan and Juli Country under the scale of 1:50000, a new fault belt was discovered at Juli Country. The fault retains sedimentary rocks dated back from Silurian to Cretaceous, and the blocks stack disorderly within which develop lots of small faults.Through the research of the tectonic zone of the fault belt, it turns out to locate in the middle of southwestern Three River Orogenic Belt and also in the joint between two level 1 structural units----Yangtze plate and Tanggula-Qamdo-Lanping-Simao fold system.Its location happens to be where Jinsha River Suture Zone combined with Ailaoshan River Fault Zone after the latter recombines with Red River Fault Zone and then extends northwestward.This tectonic location is indeed complex. Abundant evidences prove that it locates in the suture line and is a mingled tectonic zone.The mingled tectonic zone is constituted by the follows:slightly metamorphous rock-fragment sandstone, slightly metamorphous feldspar quartz sandstone, carbonaceous silty sericite slate, metamorphous sericite quartz siltstone, thin micritic limestone and a few gray-green schistose alterated mafic volcanic rocks. In the northeast part of the mingled tectonic zone,it has in northeast direction contact relationships with Late Triassic Yunnanyi group and Luo Mountain group of Yangtze Plate,and has in southwest direction contact relationships with the the Southern Star Group of Lower Cretaceous fault of Simao Block. Both sides are stable Platform deposition.The tectonic melange zone be the linear belt for the North West towards, is on the north end of convergence, open to the sweep-like sub-Saharan NW trending.The two groups fault were foung by analysis(two tectonic movement).The main ones are the pressure of NNE faults,that is the Indo-Chinese Movement Jinshajiang-Ailaoshan ocean basin closed to form the early tectonic foliation,have an important impact on the fault zone.The others are the fracture for the Southwest,Himalayan movement by the collision of Indian plate and Eurasian plate caused the formation of the late strike-slip shear foliation.There are much lens, broken rocks, structure and tectonic breccia fault traction, schistose rock,crumpled,mild deterioration in the faults.The lens axis is direct consistent with the bedding plane,is formed the extrusion of rock of the early pressure.The paper discussed the rocks mixed with material composition, geometry, paleontology, and rock characteristics,which based on the analysis of chemical characteristics, combined with previous research results, discussed the dynamics of the mechanism and evolution of model.It was obtained the evolution model of tectonic melange zone:It was deposited as a stable phase during Silurian to Late Devonian;The oceanic crust is expansion and sedimentary during Early Carboniferous to Early Permian; Subduction orogenic stage is beginning at Early Permian,which the Yangtze block to the Southwest obduction and Qamdo-Pu'er block to the northeast subduction. the downsizing of the oceanic crust is shrinking at Permian,until the early demise of the Middle Triassic oceanic crust The Yangtze Block and Qamdo-Pu'er block collided;The mid-interval of orogeny is beginning,which the east and west sides of basins stabilizing; Since ancient times,the shear slip began in the late Pliocene Himalayan orogenic.The tectonic evolution period with the Jinsha River-Ailaoshan fault zone and the Red River fault is corresponding.