摘要
自赵金科等发表了成立头十年中国三叠系总结以来,中国三叠系的调查研究工作有了很大的进展,主要是:(1)区域性三叠系的考察和调查加强了;(2)各区域三叠系的生物地层分类,包括菊石带、底栖动物(双壳类、腕足类)组合等全国性或大区域性的年代地层分类单位初步确立;(3)界线地层学、特别是二叠系与三叠系界线研究,取得一定的成果;(4)配合石油、钾盐、铜等沉积矿产普查、勘探,进行了区域三叠纪岩相古地理、碳酸盐岩以及造礁生物群的研究;(5)同位素年龄测定、古地磁学及矿物成分同三叠纪环境的研究和探索工作,也在试作并取得一定的收获。
The Triassic System of China was developed on the Gondwana,the Laurasia and the intercontinental region between them;further-more,its development was also connected with the Tethys and the Circum-pacific regions.Being formed in different tectonic units and paleogeographic settings the Triassic in China consists of various sedimentary types and associations as well as diverse biotas of different provinces.As regional geological investigation and surveying of the whole country including the border regions such as the Qinghai-Xizang(Tibet)plateau,W.Yunnan and Inner Mongolia have been completed in the past twenty years or so,a great quantity of new materials and researches has been obtained,and a clearer picture of the Chinese Triassic has made its appearance.New achievements of the research on the Triassic are embodied in the book entitled"The Stratigraphy of China——the Triassic System"(Ms in press)and this paper contains only a concise account of the book with further elucidation of certain points.The following aspects are disscussed.1.Distribution,development and regionalization of the Triassic in China.Ten stratigraphic regions are proposed(See Fig.1 and Table 1)and five points are stressed regarding the distribution,and development,namely:(1)The northern continental Triassic is marked by a geographical differentiation into(a)the mobile type(evidenced by molasse formation)occurring mostly in intermontane basins of the mountainous Northwest(the Central Tianshan—N.Qinling continental margin)and(b)stable type(fluvial-lacustrine type)present mostly in the east hilly region;(2)the Triassic of the Yangzi platform is characterized by a zonal distribution of lithofacies,which was evidently controlled by secondary structural units;(3)the Indosinian movement played an important role in the development of the Triassic in the South China folded region;(4)the co-existence of platformal-geosynclinal Triassic in the Kunlun-Qinling region of W.China is due to deep-faulting;(5)on the basis of bioand lithofacies the Yarlung Zambo River deep—faulting zone is the suture between the Gondwana and Laurasia.2.Chronostratigraphic classification of the Chinese Triassic.It is proposed to establish a chronostratigraphic classification for the marine Triassic of China based essentially on beds with Triassic pelagic biotas such as those in W.Guangxi(Lingyun,Tianlin),SW Guizhou(Qingyan,Guanling)and Mt.Qomolangma region(Nyalam),and supplemented by the Yangzi Triassic with benthic forms(Table 2).Further study on problems such as the classification of the Lower Triassic,the lower and upper boundaries of the Middle Triassic and the definition of the Upper Triassic is needed so as to improve the present scheme of classification.It is also suggested to make the Triassic in the Shaan(xi)-Gan(su)-Ning(xia)Basin as the standard for correlation of the northern continental Triassic.3.The Triassic boundary problems in China.Recent researches by us and other workers have revealed that in S.China the youngest Permian Changxingian is succeeded by the oldest Early Triassic with Otoceras woodwardi-or O.latilobatum zone or its equivalent horizon,the Ophiceras-Claraia wangi beds,that in N.China the boundary between the continental Permian and Triassic may be drawn between the Pareiasaurids-Shihtienfenia and Lystrosaurus-Chasmatosaurus or the palynological assemblage of Lundbladispoa-Taeniaesporites-Cycadopites,and that the boundary between the Triassic and the Jurassic probably has to be defined hereafter in Tibet or Guangdong—Fujian where the Hettangian transgression held sway.4.A paleogeographic sketch.The Hercynian movement brought an end to the long-existing northern geosynline(the Tianshan-Xingan geosyncline),which was turned instead into an extensive continent;a marine regime occurred south of the Kunlun—Qinling;during Early Triassic and Anisian the E.China platform was subject to the influence of an extensive transgression;in Late Ladinian the Indosinian movement brought about the uplifting of the eastern platform,while W.China continued to subside,thus preserving its geosynclinal characteristics.
作者
杨遵仪
李子舜
曲立范
卢重明
周蕙琴
周统顺
刘桂芳
刘本培
吴瑞棠
Yang Zunyi;Li Zishun;Qu Lifan;Lu Chongming;Zhou Huiqin;Zhou Tongshun;Liu Guifang;Liu Benpe;Wu Ruitang
出处
《地质学报》
1982年第1期1-21,97,共22页
Acta Geologica Sinica
