中国南方石炭纪岩相古地理

LITHOFACIES PALAEOGEOGRAPHY OF THE CARBONIFEROUS IN SOUTH CHINA

在各露头及钻井基于剖面的地层学及定量岩石学研究的基础上,采用单因素分析综合作图法,编制出了中国南方早石炭世岩关期和大塘期以及晚石炭世威宁期和马平期的各种单因素图及岩相古地理图。这些古地理图具有定量、多级别和多类型的特点。定量,即每个古地理单元的划分和确定都有确切的定量的单因素数据为依据。多级别,即已划分出三级甚至四级古地理单元。如陆和海,为一级;在海中,又划分出台地、盆地和斜坡,为二级;在台地中,又划分出滩、坪、礁,为三级;在二级盆地中,又有三级台地,此三级台地中又有滩和礁,即为四级。多类型,即每个古地理单元,尤其是第二、三级古地理单元,还可根据其岩石特征,区分为不同的类型。如台地可区分为碳酸盐岩盆地、碎屑岩台地等,盆地可区分为碳酸盐岩盆地、碎屑岩盆地、硅岩盆地、浊积岩盆地等,滩可区分亮晶颗粒滩、灰泥颗粒滩、混合颗粒滩等。石炭纪各期的岩相古地理特征可概括为“有陆有海,海中有台地、盆地和斜坡,台地中有滩和礁,台地中又有盆地,盆地中又有台地,台地和盆地间有斜坡,台盆滩类型多样”。从早石炭世岩关期至晚石炭世马平期,岩相古地理演化呈现出继承性、发展性和阶段性的特点。

Based on the study of stratigraphy and quantitative sedimentology of fundamental stratrigraphic sec-tions, according to the 'single factor analysis and comprehensive mapping method', various single factor maps and quantitative lithofacies palaeogeography maps of the Yanguan age and Datang age of the Early Carboniferous, and Weining age and Maping age of the Late Carboniferous in South China, were com-piled. These palaeogeography maps possess three characteristics, i.e.quantification, multirank and mul-titype. Quantification means that the determination of each palaeogeographical unit is based on quantita-tive single factor data. This makes palaeogeography develop to the quantitative stage. Multirank means that palaeogeographic units are classified into three ranks or more than three ranks. For instance, lands and seas are the first rank, and in seas, the platforms, basins and slopes are defined and belong to the second rank . In platforms, the banks, tidal flats and reefs are further drawn out and b he third rank. In second rank basins, there are third rank platforms which include fourth rank banks and reefs. Multitype means that each palaeogeographic unit, especially the 2nd rank or 3rd rank units, can be further divided into different types on the basis of their rock types. For instance, platforms can be classified into carbon-ate platforms, clastic platforms, etc. ; basins can be classified into carbonate basins, clastic basins, sili-ceous basins, turbidite basins, etc.; and banks can be classified into sparry grain banks, limemud grain banks, mixed grain banks, etc. . The features of the lithofacies palaeogeography of each age of the Carbo-niferous can be summerized as following. There were lands and seas. In seas there were platforms, basins and slopes. In platforms there were banks and reefs. In platforms there were basins. In basins there were platforms. Between platforms and basins there were slopes. There were a variety of platforms, basins and banks. The evolution of the lithofacies palaeogeography of the Carboniferous in South China was charac-terized with succession, development and stage.