博格达地区二叠纪原型盆地沉积充填与演化OA

The Bogda Mountains demarcate the Junggar Basin and the Turpan-Hami Basin,yet controversies persist regarding their basin-range relationship and the tectonic attributes of Permian strata on both flanks.Investigating the Permian sedimentary filling characteristics and tectono-sedimentary evolutionary processes in adjacent basins proves crucial for determining their tectonic attributes and elucidating basin-range coupling mechanisms.Building upon previous research and utilizing comprehensive datasets including borehole logs,well cores,and outcrop observations from both basins,this study employs sedimentary filling analysis and facies identification to clarify the Permian tectonic attributes,sedimentary filling patterns,and evolutionary trajectories of the Bogda Mountains and their adjacent basins.Key findings include that during the Early Permian,the study area experienced rift sedimentation under the regional extension,characterized by the formation of the sedimentary system consisting of alluvial fans,braided rivers,and fan deltas.During the Middle Permian,the study area underwent rift-sag sedimentation.In the early stage of the Middle Permian,rift sedimentation continued under regional extensional stress,accompanied by the formation of the Middle Permian bimodal volcanic rocks in the Turpan-Hami Basin.In the late stage of the Middle Permian,the sag-type deposition of littoral-shallow lacustrine and semi-deep lacustrine facies occurred as the extensional stress waned.While the end of the Middle Permian witnessed tectonic inversion with regional stress transitioning from extension to compression.During the Late Permian,continued regional extensional stress led to the large-scale rift inversion and initial uplift,transforming Bogda into a provenance area.Concurrent base-level rise facilitated the deltaic and littoral-shallow lacustrine deposition therein,marking the onset of foreland depression evolution in both basins.The tectono-sedimentary evolution indicates that the Permian basin development in Bogda area is principally driven by regional extension,with subsequent stress transformation and base-level changes serving as primary factors governing prototype basin architecture and paleogeographic configuration.