安徽宿松、繁昌地区武穴组沉积特征

通过对昌都地块古生代至中生代沉积岩相，沉积组合，古地理及生物群落与生物的深入研究及现有成果，提出了沉积地质与构造演化的五个阶段，以古中元古代的宁多群为代表的前寒武纪结晶基度形成阶段；以青泥洞群为代表的早古生代褶皱基底形成阶段，晚古生代台地型沉积为代表的稳定地块及火山弧至弧后盆地形成，演化阶段，中生代前陆盆地形成发展阶段及喜山期走滑拉分盆地发展阶段，同时，表明了介于冈瓦纳和劳亚两个超级大陆之间的特提

SEDIMENTARY CHARACTERISTICS OF THE WUXUE FORMATION IN THE SUSONG-FANCHANG REGION,ANHUI

The Wuxue Formation,a lenticular stratigraphic body distributed along the Yangtze River between Susong and Fanchang in Anhui and in the Pengze district,Jiangxi,consists of algal limestone,fusulinid limestone,sponge limestone,echinoderm limestone,oncolite dolostone and dolostone.According to the radios of clast to matrix in four sections,three sequences called basic units are easily recognized.These sequences are dominated by the normal fining upward sequences from the base upwards.The inversely graded fine coarse fine sequence almost composed of the echinoderm limestone,algal limestone and sponge limestone cemented by sparite,however,is also found,which indicates a rapidly depositional process and a barrier environment.The sponge bindstone exhibiting mega and coarse crystallized grain textures observed at the base and on the top of these units represents the products in the extremely shallow water environments where the rates of organic upbuilding were temporarily greater than those of sea level rise,This kind of depositional units is usually called organic buildups.It is inferred from tectonic settings and sedimentary characteristics that this kind of isolated geological bodies may come into existence in Guangji,Daye,Jingshan,Nanzhang and other places in Hubei.