Neotectonic Research Of The Malan Mountain–Wuxue Mountain Areas, Hoh Xil Region, Qinghai Province

Study area is located in the hinterland of the Hoh Xil protected area,north of Qinghai Province,the Highest mountain-Buka Daban Peak,South Point Hoh Xil Basin,across the Qiangtang-Sanjiang formation region(?),Bayan Har stratigraphic zones(?1)of Hoh-Aba stratigraphic area and northeast Kangxiwa-South Kunlun-Maduo formation region(?)of Muztagh-Buka Daban stratigraphic zones(?2),these two tectonic units are divided by which across the northern part of the study area East Kunlun active faults,breaking the boundaries of the two secondary structure elements.Since the Indo-China movement,the dominant tectonic activity in the study area is North East to South West squeeze shorten,Faults and folds deformed main line track to the North-West to the South East.South of East Kunlun fault rupture-Kunlun rupture NEE–SWW to pass through from the study area.The fault is a deep fracture in the formation and in the different evolution stages of the Qinghai-Tibet Plateau,the fracture has activity performance.Especially since the Cenozoic era,a significant activity of the fault makes the study area had a variety of new types of tectonic activity.Volcanic activity in the region focused on the Pliocene-Early Pleistocene,there are two main volcanic rocks: Chabaoma group volcanic and Hudongliang group volcanic.Source region of Volcanic rocks are enriched mantle of oceanic sediments and continental crust,and its sources and melting of thickened crust.But there is a big difference between the two tectonic setting: Chabaoma group volcanic formed in the plateau phase of steady uplift,rock strata occurrence nearly horizontal;Hudongliang group volcanic located in and around active faults along,partial has been broken by local fault,and showed significant volcanic features continental crust,which may be formed during faulting.Through the previous data collection and field observation,sampling and analysis,We think that the East Kunlun active faults of Malan Mountain – Wuxue Mountain region have been intense activity around since the 3.6Ma,its nature has a tensile properties while sinistral strike-slip motion.By studying the characteristics of its movement,its movement is divided into eight stages:(1)the mid-Pliocene;(2)late Pliocene-Pleistocene early on;(3)late Pleistocene-early Middle Pleistocene;(4)in the late Pleistocene early-late Pleistocene;(5)late Pleistocene;(6)early Late Pleistocene ~ Early Holocene;(7)middle Holocene;(8)late Holocene.Sun Lake-small Sun Lake pull-apart basin is the production of structure conversion mechanism,formation and movement related to the conversion of active faults movement nature,it formed about 3.6Ma ~ 2.3Ma,is currently in the growth phase.In addition,the local river terraces? planation surface features reflects the activity characteristics of the Neotectonism.The new work think that there having occurred a transition of tectonic mechanisms at late Cenozoic during the plateau uplift process,by summarizing the characteristics of Neotectonism activities in the region,and thus the uplift of the plateau phase is divided into:1,orogenic stage(65Ma ~ 23Ma);2,the first stage of building the plateau(23Ma ~ 3.6Ma);3,the second stage of building the plateau(3.6Ma so far).