Tectonic Evolution And Basin-mountain Coupling Relationship Between Kongquehe Slope And Quruqtagh Uplift

Kongquehe slope and Quruqtagh uplift are located to the northeast part of Tarim basin. The formation, evolution and coupling of Kongquehe slope and Quruqtagh uplift is related to the geological process of the South Tianshan and the Altyn Mountain. The study of the coupling and tectonic evolution is very important to reveal the geodynamic settings of the northeastern margin of Tarim Basin since Early Paleozoic.In this study, we built the tectonic-stratigraphy framework basically, through the building of the basic tectonic framework by the analysis of the boundary fault of the basin and the mountain and the dividing of the structure units of the study area, combined with the building of the stratigraphy framework by the study of the stratigraphy distribution and the major tectonic unconformity of the study area.Through the interpretation of the seismic profile of Kongquehe slope, in this study we analyze the fault characteristics and divide the structure unit. Kongquehe slope is divided into Yuli fault-nosed structure and the east slope structure. Through the integrated study of the coupling of the Kongquehe slope and the Quruqtagh uplift by the restoration of the major interpreted seismic profile of Kongquehe slope, combined with the Zircon choronology analysis of the outcrop sample and the evolution information of the samples’ apatite fission track, this study achieved four understanding as follow:1) Yuli Fault nose-shaped structure mainly reflects the superimposition of three tectonic events:Middle to Late Ordovician, the NE-SW direction spreading anticline formed; Silurian to Permian, being affected by the compressive stress generated in the subtractive and the closure of the South Tianshan Ocean, the Yuli anticline became to the nose-shaped structure with the uplift and denudation of its northern part; Jurassic, the Early Yanshanian Movement affected the Paleozoic and Mesozoic strata, and made the southward thrust whose strike direction is NWW removed, which offset the pre-exist nose-shaped structure. This research thinks the NE-SW direction spreading anticline of Yuli Fault nose-shaped structure was being formed in Middle Ordovician, the principle stress may came from the Altun Mountain, southeast to Tarim Basin.2) The east slope structure of Kongquehe slope is a southwest trending slope in the NS direction. The Weimake anticline structure reflects the evolution of the east slope structure zone. The south and north basin-mountain system suffered the Caledonian basement structural wedge’s forming, the developing of the structural wedge (the forming of the Kongquehe Fault and the major thrust fault), the indo-chinese structural wedge Stereotype, the Yanshanian Weimake anticline Stereotype (the forming of Weimake reverse thrust) and the Kongquehe fault’s strong activity in Himalayan by the affecting of the uplift of Quruqtagh.3) The tectonic evolution of the quruqtagh uplift suffered six stages: ①The formation stage of the metamorphic basement in Ar-Pt2;②The landmass convergence and the supercontinent breakup stage in Pt3;③The opening stage of the South Tianshan ocean basin;④The contraction stage of the South Tianshan ocean basin; ⑤The post-collision stage and the continental structure evolution stage; ⑥The stage of the mountains’reconstruction.4) Kongquehe fault formed after the closing of the South Tianshan ocean basin, then Kongquehe slope and Quruqtagh uplift coupled. The basin-mountain coupling mechanism is interlayer intercalation and subduction at the binding site of the Tarim plate and the Tianshan plate, a continental subduction mechanism.