Sedimentary Evolution Of The Coqen Basin In Mesozoic

Based on the field study, by combining sedimentary basin analysis with methods of the other subjects, the regional tectonic background and basic framework and basement structure and igneous rock character in the Coqen basin are analyzed. The Stratigraphic character, depositional system and facies, facies sequences and temporal and spatial distribution of depositional system, the sequence boundary signatures and parasequencs stacking pattern, palaeogeographic evolution are fully studied; The basin framework and character and forming processes are discussed; the resource potentialities of oil and gas in this basin are generally discussed. The advancements are as follow:1. Through the analyses of the tectonic and igneous rock and seismic reflection structure in Coqen basin, combing with sedimentary characteristics of the Ganba-Tingri basin in the north Indian plate, Author demonstrated oneself viewpoints about the difference of the subducting direction of Bangong-Nujiang ocean and the subducting period of Yarlung Zangbo ocean and thought that Bangong -Nujiang ocean should subduct southern direction and Yarlung Zangbo ocean should subduct in Early Cretaceous.2. Based on stratigraphic characters and sedimentary suite and magmatic activity, the stratigraphic sub-regions is divided again and the Risong-Jiagang areas where was formerly part of Mugagangri stratigraphic is belong to Risong-Gerze-Taricuo region.3. By the study of lithostratigraphy and biostratigraphy, the suggestion using different names about the Samuluo formations in Bangong lake-Nujiang suture zone, Qiekan-Guchang-Asuo rift zone and between two zones is put forward.4. Based on spatial distribution of the Langshan formation reef in lower cretaceous and Qiekan-Guchang-Asuo rift zone, the viewpoints that Langshan formation reef was mainly distributed along both sides of rift zone is put forward.5.After the detailed study of depositional system and facies, facies sequences and spatio-temporal distribution of depositional system, paleogeographic evolution,...