舞阳凹陷始新统核桃园组物源示踪与砂体展布模式

PROVENANCE AND DISTRIBUTION PATTERN OF THE SANDBODY OF EOCENE HETAOYUAN FORMATION IN WUYANG DEPRESSION

依据砂岩阴极发光、碎屑锆石形态及锆石U-Pb测年等资料,对舞阳凹陷核桃园组的物源进行了综合分析,认为舞3和舞8井核二段的物源来自于舞阳凹陷的南缘隆起区,与前人认识完全不同。根据这一认识,对舞阳凹陷核桃园组沉积体系与砂体分布进行了重新编图,并提出了新的砂体展布模式。核桃园组沉积时期舞阳凹陷内部砂体展布呈现明显的不对称性:凹陷南部斜坡带辫状河三角洲砂体向凹陷内部推进距离远,分布面积大,而凹陷北部陡坡带扇三角洲砂体沿边界断裂呈小朵状分布,砂体面积小。

.An integrated provenance analysis has been performed for the sanbodies of the Hetaoyuan Formation in the Wuyang Depression based on cathodoluminescence slice and the shape and chronology of zircon debris in the sandstone. The result indicated that the source of the sandbodies in the Second Member of Hetaoyuan Formation disclosed by well Wu3 and Wu8 came from the southern uplift of the depression. It is an opinion different from previous studies. Then a new sandbody distribution map and a depositional model were put forward by the authors in this paper. It is seen from the map that the spatial distribution pattern of sandbodies is remarkable different in the south from the north, The braided river delta stretched far into the depositional center on the southern slope, whereas the fan deltas on the northern steep slope only occur along the boundary fault in small patches.