贵州几个区域地质问题的研究现状及存在问题

Some Advances in and Disputes on Understanding of the Regional Geology of Guizhou

本文简要的介绍了8个有关贵州区域地质问题的研究现状及存在问题：①贵州大地构造可分为扬子陆块、江南加里东造山带、右江印支一燕山造山带三个单元；②贵州有老于梵净山群、四堡群的陆壳；③江南加里东造山带的构造样式在贵州表现为平卧褶皱及逆冲叠瓦扇构造。由大面积前寒武系出露而构成的雪峰隆起在中三叠世以前并不存在，它是印支-燕山期由南东向北西逆冲-推覆的结果；④右江地区是印支-燕山期的造山带，地壳结构可与Catter建立的大陆地壳结构模式相比拟，其区别在于右江地区具有更明显的分层、分块的不均一性；⑤野外追索及所含化石群的研究表明：领组下部的时代应属早三叠世晚期。领组与下伏地层之间系区域性的超覆不整合面，在局部地区其下有玄武岩。这一事实表明：东吴运动似乎发生在早二叠世晚期．而不是发生在早晚二叠世之间；⑥瓮安晚震旦世早期磷块岩中，早已发现世界上最早的生命性分化的痕迹。最近又发现可疑动物胚胎化石和完整的海绵个体及海绵骨针。海绵化石及海绵骨针能得到证实和公认，这将是目前已知的世界上出现最早的动物化石，也将对寒武纪生物大爆炸理论给予巨大的冲击。风冈硐卡拉早志留世晚期维管植物是目前国内已知的层位最低的维管植物群；⑦暴露环境下碳酸盐沉积──钙结?

This paper presents some advances in understanding of the regionalgeology of Guizhou over recent years. They are outlined as the following eight aspects: (1) the Indosinian-Yans ban tan Youjiang orogenic belt to which mineralizationof most sedimentary- rock- hosted disseminated gold deposits in southwestern Guizhouare perhaps both spatially and genetically related could be considered to be split fromthe early tectonic division - the two major units of the Precambrian Yangtze cratonand the Jiangnan Caledonides; (2) the recent regional geological investigations haveshowed that there exists an older continental crust than two Groups prior to 150 Maof the Fanjingshan and the Sibao, exposed separately in the Faming Mountainous areaof northeastern Guizhou and in southeastern Guizhou adjacent to north of Guangxi;(3) the structural style of the Jiangnan Caledonides is expressed as a set of recumbentfolds characterized by thrusting imbricated fans, and the Xuefeng uplift which is comPOSed of the Precambrian rocks exPOsed to a large extent has not emerged until theobduction northwestward during the Indosiman- Yanshanian orogeny; (4) the crustalstructure of the Indosintan- Yanshanian orogenic belt in the Youjiang area of sonth-western Guizhou is comparable with the continental crust pattern established by Catter; and the difference is found in relatively well crustal layering and in inhomogeneous crustal fragments in the Youjiang area; (5) the Linghao Formation constrainsin age the Dongwu movement which was previously considered to take place betweenthe early and late Permian. The fossil data available, however, indicate that at leastthe lower Linghao Formation is the late Early Permian age. In addition, the evidencethat there is a regionally unconforrnability of overlap boundary between the LinghaoFormation and its underlying sedimentary rocks as well as local existence of basalt underlying the Linghao Formation also strongly support that the Dongwu movementseems to have begun in the late Early Perrnian; (6) in phosphorites of the early LateSinian in the Weng'an area of central Guizhou, the discovery of the trace of the worldoldest life secretion, as well as recently found animal embryonic fossils and intact individual sPOnge and sponge-spicule-which have been confirmed to be the oldest animal fossil in the world up to date, is undoubtedly a challenge to the theory of theCambrian biologic explosion; the vascular plant community of the late Early Silurianage found at Dongkala of Fenggang county, northern Guizhou,\is known as havingthe lowest location stratigraphically in China; (7) a discovery of the carbonate sedi-mentation 0f the mid-Triassic time in an exposure to weather - marked by an encrust-ed calcium sediment and ancient karst which have ever been regarded as a S-type reefbank for a long-term - will make useful contributions to an insight into the sedimenta-tion during the mid-Triassic throughout Guizhou; and (8) the latest orogeny inGuizhou began between Paleqene and Neogene resulting in the folding and faulting ofthe Paleogene sedimentary rocks.