南鄱阳坳陷推覆构造特征

南鄱阳坳陷地质结构具有“上张下压”的叠合盆地特征。下构造层地质结构的显著特征是发育推覆构造,由北向南推覆,在坳陷南缘与官帽山逆冲系相向逆冲形成向塘—二甲村对冲带。其内部结构受推覆构造影响呈现条带状分布的残留向斜,部分地区呈现为逆冲超叠单斜片。坳陷内的推覆构造与萍乐坳陷北部九岭推覆构造体系实属同一构造体系,由九岭向东延伸至波阳,再向东与高台山逆冲系相接,主要推覆活动期为燕山运动中期。

Features of Nappes in Nanpoyang Depression

Based on available new geological-geophysical data,it is suggested that Nanpoyang Depression is characteristic of a texture of superimposed basin with pull-apart structure in the upper part and compressed structure in the lower part.The lower part is a nappe which overrides southwards.The Xiangtang-Erjiachun ramp zone in the southern part of the Depression is caused from ramping of the nappe on the north with the Guanmaoshan thrust system on the south,in which the upper Paleozoic hydrocarbon-generating and-accumulated rocks are preserved well.The internal structure of the ramp zone shows a banded remnant syncline or local overlapping thrust sheets caused typically by Jiuling nappe system.In fact,the nappe in Nanpoyang Depression belongs to same tectonic system with well-known Jiuling nappe system for it extended eastwards from Jiuling Mountain and joined with Gaotaishan thrust system in the east of Boyang.It napped during the middle Yanshanian orogenic movement(J3-K1).