层序地层与岩相古地理编图——以中国南方泥盆纪地层为例

SEQUENCE STRATIGRAPHY AND COMPILATION OF LITHOFACIES AND PALAEOGEOGRAPHIC MAPS——AN EXAMPIE FROM THE DEVONIAN STRATA IN SOUTHERN CHINA

岩相古地理及古地理学的研究,在我国已有相当长的历史并有着十分丰硕的成果。各家以不同的理论为指导、采取不同的编图方法,从不同的研究角度编制了中国的岩相古地理图。刘鸿允(1955)以古生物地层学的理论为指导,编写了我国第一部古地理学的专著《中国古地理图》,从此,正式揭开了中国古地理学研究的序幕;卢衍豪等(1965)以期为单位,编制了中国寒武纪各期的岩相古地理图;关士聪等(1984),以大地构造学和沉积学的理论为指导,编制了《中国海陆变迁海域沉积相与油气》专著。

This paper focuses on the relationship between sequence stratigraphy and compilation of lithofacies and palaeogeographic maps. The Devonian strata in southern China may be divided into four depositional sequences in terms of sequence boundary unconformity characterized by fluvial rejuvenation and condensed sections consisting of biostrome and tentaculitid-bearing siliceous rocks. Their times are represented by the Lochkovian to middle Emsian, late Emsian to early and middle Givetian, late Givetian to Frasnian and Famennian, respectively. The depositional sequences cited above are time-equivalent because the sequence boundary unconformity and the boundary between the depositional systems tract are time-equivalent. Therefore, the lithofacies and palaeogeographic maps compiled on the basis of the point of view and method of sequence stratigraphy approximately coincide with the distribution of seas and continents, indicating the framework of sedimentary facies and the associated information about sedimentation and tectonic activity in the basin and basin evolution. The compilation of the Devonian lithofacies and palaeogeographic map of South China has been made by means of the depostional sequences as the basic chronostratigraphic units, the depostitional systems tract as the compilation unites, the sequence boundary unconformity as the isochronous or instantaneous surfaces, and distinctive sedimentary facies in the depositonal systems tract as the compilation elements of the corresponding isochronous surfaces.