层序生物地层学在柴达木盆地中的应用及展望

在单井高分辨率层序地层分析基础上，应用层序生物地层学原理，以柴达木盆地西部咸东1井和咸8井为例，在新近系上油砂山组划分了一个层序生物地层单元，作为与下油砂山组分界的标志。以红柳泉-跃进地区为例，在古近系下干柴沟组下段划分了两个层序生物地层单元。连井等时对比发现，下干柴沟组下段标志性的“红层”顶界由西向东时代变新，反映了在基准面旋回的波动过程中湖泊范围随时间由西向东的扩大。在乌南地区，进一步将层序生物地层单元与地震地层相结合，在标准化石的约束下建立了该区层序生物地层格架，为柴西南地层划分对比建立了标准。研究认为，古生物、地震和高分辨率层序地层学的结合是层序生物地层学研究并建立区域等时地层格架的良好途径。

Application of sequence biostratigraphy in the Qaidam Basin and its prospects

An integration of high resolution sequence stratigraphic and sequence biostratigraphic analysis ofwell logs allows the recognition of a distinctive sequence biostratigraphic unit from theNeogene Shangyoushashan Formation of the wellXiandong-1and the wellXiandong-8in western Qaidam Basin，NW China.The unit is distinguished from the Xiayoushashan Formation in the samewell of the same area and is used as a boundarymarker.Two comparable sequence biostratigraphic units are also recognized from the lowerPaleogene Xiaganchaigou Formation in the Hongliuquan Yuejin area of the basin.Sequence biostratigraphic correlations show that the top boundary of the remarkable“red bed”in the lowerXiaganchaigou Formation gets younger eastwards，indicating an eastward lake expansion following fluctuations of base-level cycle.In theWunan area of the basin，a sequence biostratigraphic framework is constructed under the constraint of characteristic fossils by integrating sequence biostratigraphic unitswith seism ic stratigraphy，providing standards for regional stratigraphic division and correlations in southwestern Qaidam Basin.Accordingly，the integration of biostratigraphy，seism ic stratigraphy and highˉresolution sequence stratigraphy is a powerful approach in sequence biostratigraphic study and establishing regional isochronous stratigraphic frameworks.