摘要
江西省茅口—龙潭期地层研究的较为详细,可分为3区6小区,反映出当时古地理条件下所形成的不同沉积相带,它们沿走向相当稳定,沿倾向则有规律递变。但目前这种有规律的分布已经错乱,通过地层对比推知在武夷山、武功山及九岭山等地均发生过较大规模的水平位移。正是这种水平位移导致了江西省二叠纪沉积相带的畸变与古地理图失真。目前这些山区的核心部位均无盖层,其原因不仅仅在于风化剥蚀,构造剥蚀可能是更重要的因素。
Thrust mappes and gliding nappes are well developed in Jiangxi, which result-ed in tectonic displacement and deviation of sediments from their original po-sitions. If the strata of a certain age change regularly, one would determine theirdisplacement nature, moving direction.and distance according to the anomalousdistribution pattern of the strata. The Permian, especially Maokou'an and Longtanian, strata in Jiangxi Prov-ince were studied in more detali.They may be divided into 3 regions: the Yang-tze, Jiangnan and South China regions which may be subdivided into 6 areas.In fact, they reflect various sedimentary facies zones. Their lithological are bas-ically persistent along the strike but show regular and rapid chang along the dip.The distribution of these strata has now broken with the due regularity. Thusthis paper maintains that in many places the strata have been displaced andare not in the original locations. The Permian southern of Shangrao came fromChongan, Jianyan and Shaowu in the northern part of Fujian Province. ThePermian in Anfu,southern Gro'an and Fengcheng should have been contiguous to each other as their sedimentary features are quite alike, although at presentthey are seperated by the Wugong Mountains (Fig. 2). The strata on both sidesof the Jiuling Mountains, e. g. in Wanzai, northern Gaoan, Ruichang and De'an,have been displaced too. The Permian in the Wanzai area situated at the southfoot of the Jiuling Mountain should have adjoined that of the Jiuling area situ-ated at the north foot of the mountains(Fig. 3). The distance of tectonic displace-ment in many places is about 20 to 50 km. Such displacement inevitably causedthe distortion of the sedimentary facies zone and the lacking of fidelity of apalaeogeographic map (Fig. 1). There are no sedimentary covers in the centres of the Wuyi, Wugong andJiuling mountains; however, there were sedimentary covers in these places. Thecause for their disappearance is mainly due to tectonic denudation rather thanexogenic denudation. In the author's opioion, the age of tectonic displacementshould be quite young, about late Yanshanian or even Himalayan.
出处
《地质论评》
CAS
CSCD
北大核心
1993年第3期268-275,共8页
Geological Review
关键词
地壳
二叠纪
沉积相
畸变
古地理图
distortion of Permian sedimentary facies zone
lacking of fidelity of paleogeographic map
tectonic denudation
tectonic displacement
Jiangxi
