Sedimentology and stratigraphic evolution of the fan delta at the Badaowan formation (lower Jurassic), Southern Junggar Basin, Northwest China
Sedimentology and stratigraphic evolution of the fan delta at the Badaowan formation (lower Jurassic), Southern Junggar Basin, Northwest China
复制标题
准噶尔盆地南部八道湾组（下侏罗统）扇三角洲沉积学及地层演化
DOI：
10.1007/s12517-015-2242-4
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发表时间：
2016
影响因子：
--
通讯作者：
Chen Bintao
中科院分区：
文献类型：
--
作者：
Tan Chengpeng;Yu Xinghe;Li Shunli;Shan Xin;Chen Bintao
对准噶尔盆地南缘四棵树剖面扇三角洲沉积学及地层演化进行了详细研究。八道湾组扇三角洲沿着剖面连续出露，显示了河道复合体、河道砾岩和粗砂岩、泛滥平原泥岩和薄煤层、湖相泥岩的地层地理分布。在沉积特征重建的基础上，建立了扇三角洲沉积模式。通过剖面解剖，将河道砂体划分为3种类型：混合型、过渡型和孤立型，分别对应于辫状河道、辫状河道转化为分流河道（转化部分）和分流河道的成因。在野外测量了3种河道砂体的宽度（W）、厚度（T）和宽厚比（W/T）。从混合砂体到孤立砂体，砂体的宽度、厚度和宽厚比逐渐减小。基准面旋回及其相应位置的变化控制着砂体的特征、沉积学成因和变化。河道砂体的尺度与可容纳空间/供沙比（A/S）成反比，随着A/S的增大，河道砂体的尺度减小。随着基准面的升高，河道砂体的比例、厚度、连通性、粒度和规模均减小。
A detailed study of sedimentology and stratigraphic evolution of the fan delta at the Sikeshu section in the southern edge of the Junggar basin was conducted. The fan delta of the Badaowan formation is exposed continuously along the cross section, which shows the stratigraphic and geographic distribution of channel complexes, channel conglomerates and coarse sandstones; flood plain mudstones and thin coal seams, and lacustrine mudstones. Eventually, a fan delta sedimentary model has been established based on the reconstruction of sedimentary characteristics. Based on dissection of the section, channel sand bodies can be divided into three types: amalgamated, transitional, and isolated, which correspond to the origin of braided channels, braided channels transforming into distributary channels (transformation part), and distributary channels respectively. The width (W), thickness (T), and width/thickness ratio (W/T) dimensions of the three types of channel sand bodies were measured in the field. The width, thickness, and width/thickness ratio gradually decrease from amalgamated to isolated sand bodies. The characteristics, sedimentology genesis, and variation of sand bodies are controlled by the variation of base-level cycles and their relevant position. The dimensions of channel sand bodies are proportionate to accommodation/sediment supply (A/S) ratio inversely, which the dimensions decrease with the increase in theA/Sratio. Moreover, the proportion, thickness, connectivity, grain size, and dimensions of channel sand bodies decrease in accompany with the rise of base level.