Petrographic and Geochemistry Characteristics of the Upper Cambrian Dolomites and Dolomitization mechanism in Southern North China Basin

The upper Cambrian dolomite of southern north China basin can be divided into crystalline dolostone, remnant grain dolostone and straticulate dolostone. According to the structure and mechanism, an origin mechanism of upper Cambrian dolomites was studied by petrology and geochemistry method. Crystalline dolostone shows medium-weak jacinth light in cathode luminescence,with low content of Sr, this kind of dolomite is buried dolomite. Remnant grain dolostone contains biological debris, oolitic and calcirudite, which dolomite mineral surface filth,appears weak orange red in cathode ray,Sr close to 0,this dolostone resulted from burial and compaction water. Straticulate dolostone resulte from penecontemporary dolostone, which dolomite small, appears dark brown, high Sr content, and in which parallel laminae, bird-eyes and mud-cracks developed.