鄂尔多斯盆地西缘晚三叠世“古脊梁”隆升地质证据及盆地原型西部边界的确定

Geological Evidence of “the Archaic Uplift” of Late Triassic in Western Margin of Ordos Basin and Identification of Original Boundary in the West of Basin

鄂尔多斯盆地西缘“古脊梁”晚三叠世的构造特征是一意义重大而又长期争论的基础地质问题。通过区域角度不整合及“古脊梁”东西两侧沉积岩岩性、岩相综合特征分析，提出了“古脊梁”为一动态的隆升和下沉的构造演化带的新认识。认为，鄂尔多斯盆地西缘“古脊梁”晚三叠世为构造隆升带，上三叠统延长组长1～长7油层组沉积期，“古脊梁”构成鄂尔多斯盆地的西部边界，且为盆地西部沉积的物源区。

The late Triassic structural feature of'the archaic uplift'in western margin of Ordos Basin was a significant basic geological issue of long-term argument.Through integrated feature analysis of regional and angular unconformity,lithology of sedimentary rock and rock facies on both sides of east and west of'the archaic uplift',a new cognition that'the archaic uplift'was a structural evolution zone with dynamic uplift and sinkage was put forward.It is considered that in the period of Chang7to Chang1reservoirs of Yanchang Formation in the Upper Triassic System,'the archaic uplift'forms the western boundary of Ordos Basin,and it is the depositional source area of west Ordos Basin.