Deformation And Research Activities In Eastern Tibet Markam Zhuka Fault

Mangkang county of Changdu district in Tibet plans to build a number of projects,Including hydraulic engineering,road engineering,tunneling engineering. Located in the Sanjiang orogenic belt. The planning construction projects distance from one construction unit of Lanchangjiang belt with only one thousand meters. A few hundred meters from the regional fault of Zhuka. The activity of Zhuka fault there is a big controversy. In particular aspects of inadequate structure research.Zhuka fault as a large-scale regional fault zone the closest to the planning project. Fracture of geological features is particularly important.In Rongqu river district the Zhuka fault research of geometry distribution through the control of drilling and adit. In study area Zhuka fault can be divided into the southern section(Ronguhe)?North Section(Serugou); the southern section substantially along the Rongqu ruver distribution,fault strike:NNE-nearly SN-NNW,Overall it's like the protruding arcuate. The PD23 located in the left bank of the Rongqu river complete revealed Zhuka fault belt,Clearly shows the deformation?zonation ?alteration characteristics. On the disk(SW) for the Middle Triassic mylonitized dacite of Zhuka group. Footwall of the Huakaizuo group of Middle Jurassic,constructed by the black calcareous schist?pelitic schist structure and purplish red conglomerates?pebbled sandstone. occurrence of the Zhuka fault:the fracture surface strike NW-SE, inclination of 238°,inclination angle of 78°;the broken belt bandwidth about 30 cm,broken belt on the disk composition by the deformation of the moyite. Developmental gray granite of powdery rock and granulitic rocks, direction significantly,at edge of broken belt we can seen traction deformation,indicates Zhuka faults is a reverse fault. The northern section of Zhuka fault(Serugou),the fracture surface strike SW,inclination angle of 83°,the broken belt bandwidth about 5-20 cm,Development limestone breccia structure ?strong cleavage belt and the lens belt,The main fault surface development 2-5cm khaki powder rock. The upper disk fault consist of purple microcrystalline massive rhyolite,footwall fault consist of the strong cleavage gasification thin layer fine – micrite. Cleavages inclination of 198°,inclination angle of 79°, along the cleavage direction of the development a large number of calcite veins,partial cleavage occurred late crumpled;While cleavage in the development of a strong rheological character boudinage limestone lenses,Showed the brittle ductile deformation. According to the fault zone within the lens arrangement can Judge the nature of the thrust fault.Zhuka no active fault,Based primarily on there:(1)It does not show active tectonic geomorphology,In addition to in the Rongqu river estuary the development along the river,the rest from the foothills by, No continuous linear activities structural features,so the fault has no active tectonic geomorphology mark.(2)Earthquake did not occur along the fault,which is no seismic activity show.(3)No exposed hot springs along the fault,which is no geothermal activity show.(4)Overlying and adjacent Quaternary no disturbance?neo-tectonic and active Tectonics of fold?fault. Rqongqu river Estuary ?-? terraces no deformation. This district ? terraces the age is more than 100 thousand years,since the late Pleistocene,Zhuka fault has no activity.(5)The quartz shape morphology of fragmental material mainly consist of middle – deep erosion quartz, reflecting the Pliocene- Early Pleistocene active features,non-active since the Pleistocene. Zhuka fault and secondary fault ESR ages of(215.5±20)thousand years?(133.9±8)thousand years,also shows that Zhuka fault is non-active. So the main fault activity date for early- middle Pleistocene, since the late Quaternary non-active.