鄂尔多斯地区南部与东秦岭早古生代的关系和演化——以中层序(mesosequence)观点述之

鄂尔多斯地区南部和东秦岭北部是华北稳定陆块与秦岭海槽之间的过渡带．早古生代可划分为５个中层序（ｍｅｓｏｓｅｑｕｅｎｃｅ）．ＭＳ－１．包括下寒武统及中寒武统徐庄组，为混水台地沉积体系，时间跨度在３５Ｍａ；ＭＳ－２．包括下寒武统张夏组、上寒武统和下奥陶统冶里—亮甲山组，为清水台地沉积体系，时间跨度近３７．９Ｍａ；ＭＳ－３．包括下奥陶统马家沟组和峰峰组，为蒸发型台地沉积体系，时间跨度近３１Ｍａ．三者组成显生宙第一大层序（ｍｅｇａｓｅｑｕｅｎｃｅ），形成一巨大沉积旋回，为地壳动力伸张所成；ＭＳ－４．包括赵老峪组，为弧后盆地形成的斜坡沉积体系和盆地沉积体系，时间跨度１７Ｍａ；ＭＳ－５．系上奥陶统，包括背锅山组、上店组、两岔口组等，为残留海台地型沉积体系．这两个中层序形成显生宙第二大层序的主体，形成一巨大沉积旋回，为地壳动力挤压所成．

DIAGENESIS STRATIGRAPHY AND SEQUENCE STRATIGRAPHY

Current sequence stratigraphy is studied in a macro view through outcrops and log and seismic reflection. A large number of materials show that many sequence boundaries are very difficult to distinguish by macrocosm. It hinders the correct division of sequences and the study of sequence stratigraphy. Any sequence undergoes transformation of diagenesis. Therefore diagenesis stratigraphy is closely related to sequence stratigraphy. Especially, sequence stratigraphy is very closely related to epidiagenesis. Thus they form regional marks of diagenesis, such as dissolution, silicification, dolomitization, soil formation, metasomation etc.. Therefore, the sequence boundary of concealment can be identified by means of micro research of diagenesis.