河北宣东矿区下花园组沉积环境与聚煤特征

通过对宣东矿区下花园组的岩性相、垂直层序及砂分散体系等分析,认为其沉积环境为内陆山间断陷盆地之冲积扇—湖泊体系。宣东矿区为断陷聚煤盆地的一部分,盆缘断裂位于该区东北部外围,冲积扇源自北东向,延伸和推进方向为南西。下花园组各岩性段代表了冲积扇向湖泊不断延伸、推进过程中不同阶段的沉积产物,扇前泥炭沼泽是最有利的聚煤场所。该结论改变了过去河流体系背景下河漫泥沼聚煤的观点。宣东二井东部外围的李家庄、郭家庄一带,所处沉积相带位置与一、二井一致,同属冲积扇扇尾及前缘部位,地层充填序列也应相同,是找煤的有利区域。

Xiahuayuan Formation Depositional Environment and Coal-accumulation Characteristics in Xuandong Mine Area,Hebei

Through analyses of Xiahuayuan Formation lithofacies, vertical sequences and sand dispersed system, Xuandong mine area, considered that its depositional environment belongs to alluvial fan-lacustrine system of inland intermontane fault basin. The Xuandong mine area is a part of coal-accumulation fault basin, margin fault of the basin is located at northeastern periphery of the area, alluvial fan stem from northeast, extending and pushing to southwest. Each lithologieal section of Xiahuayuan Formation represents different stage depositional products during alluvial fan gradually extending and pushing process, while the fan front peat bog is most favorable coal accumulating site. The conclusion has changed the old point of view i.e. overbank peat bog coalaccumulating under the fluvial system. In Lijiazhuang, Guojiazhuang district at the eastern periphery of the Xuandong No.2 mine, their sedimentary facies zone is the same with Xuadong Nos.1 and 2 mines all belong to distal fan and fan front parts, and strata filling sequences should be the same, thus the favorable area for coal looking.