摘要
将旋回地层学（ｃｙｃｌｏｓｔｒａｔｉｇｒａｐｈｙ）和层序地层学（ｓｅｑｕｅｎｃｅｓｔｒａｔｉｇｒａｐｈｙ）有机地结合起来并应用沉积学和地层学的基本理论研究了陕西省商南地区上泥盆统王冠沟组旋回层序级别的划分、层序边界特征、三级旋回层序内部组成特征以及米级旋回的沉积特点。王冠沟组可以识别出１．５个三级旋回层序，４个四级旋回层序，共发育８６个米级旋回，归属８大类。三级旋回层序发育低水位体系域（ＬＳＴ）、海进体系域（ＴＳＴ）、高水位体系域（ＨＳＴ）和陆架边缘体系域（ＳＭＳＴ）。第一个三级旋回层序的底界面为Ⅰ型层序界面（ＳＢ１），顶界面为Ⅱ型层序界面（ＳＢ２），明显地具间断－加积旋回（ＰＡＣ）沉积特征。通过详细的旋回层序研究以及与中国黔南和世界晚泥盆世弗拉斯阶海进－海退旋回进行比较研究，并结合区域地层对比研究，商南地区上泥盆统王冠沟组旋回发育不完整，推测可能地层发育不全。
Through researching the hiarachy division of cyclic sequences, sequence boundary characteristics, interior framework of third order cyclic sequences and depositional features of meter scale cycles of upper Devonian Wangguangou formation in Shangnan, Shaanxi based on the cyclostratigraphy, sequence strigraphy, sedimentology and stratigraphy, it can be divided into 1 5 third order cyclic sequences, 4 fourth order cyclic sequences and 86 meter scale cycles in Wangguangou formation. The lowstand system tracts(LST), transgressive system tracts(TST), highstand system tracts(HST) and shelf marginal system tracts(SMST) were well produced in the third order cyclic sequences. The first third order cyclic sequence developed Ⅰ type(SM1) bottom sequence boundary and Ⅱ type(SB2) top sequence boundary with punctuated deepening depositional features. Compared with the transgressive regressive cycles of the Late Devonian Frasnian in the southern Guizhou Province in China and the globe, the cyclic sequences were well developed in Wangguangou formation of upper Devonian in Shangnan area, And meantime, on the basis of the regional stratigraphy correlation, it is suggested that the upper part of Wangguangou Formation be absent.
出处
《西安工程学院学报》
1998年第2期19-23,共5页
Journal of Xi'an Engineering University
关键词
层序地层学
旋回层序
上泥盆统
陕西
商南地区
cyclotratigraphy, sequence stratigraphy, cyclic sequence, the upper Devonian, Shaanxi province
