柴西北区碱1井下干柴沟组上段高频层序特征

High–frequency Base Level Cycle Sequence Feature for the Upper Member of the Lower Ganchaigou Formation of Well Jian1 in Northwestern Qaidam Basin

依据柴达木盆地古近系咸水湖盆湖泊沉积发育特征,建立了碱1井下干柴沟组上段E23滨浅湖沉积模式,总结了滩坝砂沉积的7种微相发育特征,归纳出对应于湖平面上升至高水位期和湖平面下降至低水位期两类滨浅湖沉积微相组合体系。应用陆相高分辨率层序地层学原理,构建了碱1井E23的基本旋回模式,划分了69个短期旋回、4个中期旋回和2个长周期旋回,总结了高频基准面旋回层序地层的成因和特征,并探讨湖相碳酸盐岩沉积在高分辨率层序地层研究中的意义,为揭示柴达木盆地西部古近系干旱环境下的层序地层基本特征奠定良好基础。

AccordingtosedimentaryfeaturesofTertiarysalinelakeofQaidamuBasin,shore–shallowlakesedimentarypattern for the upper member of the lower Ganchaigou Formation（E 23）of Well Jian1 was established.Based on the summary about characteristicofseventypesofmicrofaciesforbeach–barsedimentaryregion,twokindsofassembledsystemforshore–shallow lake sedimentary microfacies are concluded,separately corresponding with lake–level movement two–period of lake–level rising to highstand and lake–level falling to lowstand.By applying of the high resolution sequence stratigraphic theory and method about terrene and construction of the basic base level cycle pattern,69 short period cycles or 4 middle period cycles or 2 long period cycles for the upper member of the lower Ganchaigou Formation of Well Jian1 are built up.By analyzing the genesis and feature of the high–frequency base level cycle sequences,the significance of carbonate sedimentary under lacustrine environment in study of the high resolution sequence stratigraphy is further discussed.The results of research in this study may deliver important geological information for the basic feature of the sequence stratigraphy under the arid environments of Paleogene System in Qaidam Basin.