中国南方寒武—奥陶纪大陆斜坡的特征、演化和有关矿产

寒武—奥陶纪,中国南方发育着一个壮观的大陆斜坡。斜坡规模长约二干多公里、宽几十至几百公里,在其范围内,拥有各种各样的大中小型金属和非金属矿床,特别是磷、钒、钡、钼、镍、铜、金、银、锰、石煤和油气。据研究:该斜坡带有八大类沉积物类型即岩崩、滑移、滑塌沉积等和三种横向沉积模式,所谓缓坡、加积型边缘和跌积型边缘,还有四种垂向演化类型,即推进式、后退式、直立式、淹没式。斜坡带的生物群落属台地和盆地的混合型,或者互相渗透的过渡型,此外,尚有一些特有的生物种属和遗迹化石。该斜坡带有沉积单斜构造、重力滑动构造、同沉积断裂构造和隆起构造四种重要的构造形式。 寒武—奥陶纪华南不存在“江南古陆”,应为一长期持续下降的深水斜坡一陆隆环境。华南古大陆边缘曾经历了裂谷作用(?—Z_1)、被动大陆边缘(Z_2—O_1)和闭合造山(O_2—S)三个阶段。作者对斜坡带中的沉积磷矿、重品石矿、石煤矿、锰矿、金银矿化层及油气资源进行了分析和探讨,指出华南古大陆斜坡带是十分有利的成矿域。

CHARACTERISTICS,EVOLUTION AND RELATED MINERAL RESOURCES OF THE CONTINENTAL SLOPE DURING THE CAMBRIAN-ORDOVISIAN IN SOUTHERN CHINA

During the Cambrian to Ordovisian period,a very magnificent continental slope occurred in Southern China. According to the data,that slope is rare in China and abroad,both on the slope scale (about 2000km in length,tens to hundred kilometers in width) and quantities of mineral resources (metal and nonmetal deposits in large, middle or small sizes, especially P, Ba, V, Mo, Ni, Cu , Au, Ag, Mn,stone coal,oil and gas). On the basis of the study, the author discovered that; (1) There were eight sediment types (such as rock avalanche, slide, slump deposits, gravity flow, contour current ,upwelling current deposits, etc. )and three kinds of sedimentary models (ramp, accretionary margin and by-pass margins) and four types of morphologic evolution (aggrading,retreating,upbuilding and drowned). (2)In the slope zone, biota were charactered by mixing or transition between that of platform and basin, besides, there were still special biospecies and trace fossils. (3) There were four important geological structures:sedimentary clinothem,gravity slide,symphitic sedimentary fracture and uplift structures. (4)There were no "Jiangnan Old Land " during the Cambrian to Ordovisian period in Southern China,and the place was then occupied by deep-water slope to contiental rise environment in long -term descending. (5)Paleocontinental margin in Southern China underwent multistage evolution of rift (? - Z1) ,passive margin (Z2-O1) and closure orogeny (O2 -S). In addition,the author analysed and discussed phosphorite,baritite,stone coal,manganese deposits,golden and silver mineral beds,oil and gas resources in the slope zone,and pointed out that paleocontinental slope in Southern China was a very favoaable metallogenic zone.