Sedimentary Characteristics And Environmental Evolution Of Devonian System In Hatu Moutain Area Of Western Junggar,Xinjiang

This dissertation is object on the Sedimentary Strata of Devonian Kulumudi and Baerleike Formations in Hatu Mount Area of Western Junggar.based on a systematic study of its field occurrence,rock assemblage,sedimentary age,sedimentary environment and its evolution,achieved the results as follows:1.The Devonian system in Hatu Mount area is a set of clastic rock-volcanic rock strata,which can be divided into Kulumudi Formation and Baerleike Formation by a set of stably extending siliceous rocks as the dividing line.The two formations are in integrated contact.2.The latest U-Pb age of tuff detrital zircon from the Kulumdi Formation is 378±9Ma,dating to the Early Late Devonian,which proves that its geological age is from the Middle Devonian to the early Late Devonian.Detrital zircon indicates that the Boskul-Ji Cheng magmatic arc of Early-Middle Devonian provided the main source for the formation.3.U-Pb dating of detrital zircon from tuffaceous sandstone of Baerleike Formation indicates that its upper age limit is 373.4±2.9Ma,which proves that its geological age is the end of Late Devonian Frazier stage,and detrital zircon indicates that the Middle-Late Devonian Boshkur-Chengji magmatic arc provided the main provenance for this formation.4.The characteristics of rock assemblage,sedimentary structure and clastic rock grain size analysis of the Kulumudi Formation indicate that the formation is of Tidal flat facies5.The characteristics of rock assemblage,sedimentary structure and clastic rock grain size analysis of the baerleike Formation indicate that the formation is of Lagoon-shallow marine shelf facies deposition.6.The Hattu Mount in Devonian period is a shallow sea environment with no sedimentary records.From the Middle Devonian to the Late Devonian,along the Baiyangzhen-Tiechanggou-Tuoli area,the Kulumudi Formation and Baerleike Formation represented the tidal flat-shallow marine shelf facies deposits..In the late Late Devonian,the crust in Tiechanggou-Hatu Mount area was uplifted and denuded,and no sedimentary records were found.