克拉通盆地的地层层序格架──以贵阳乌当奥陶系为例

Framework of Stratigraphical Sequence in Craton Basins An Example from Ordovician System in Wudang, Guiyang

本文重点讨论了克拉通盆地地层层序格架的几个间题，如桑德（Ｓａｎｄｅｒ）法则的肯定和认识、旋回含旋回等。并且认为对克拉通盆地地层层序格架进行研究时，应先从“米级旋回层序”（五级或四级旋回）入手，研究其垂直叠加状态，然后归纳和识别出更长周期的层序，从而建立一个点的地层层序格架，由点向面建立整个盆地的地层层序。最后以贵阳乌当奥陶系为例，建立一个该地区的包含不同旋回级次的地层层序格架，即３个层序、６个亚层序，每一个亚层序由数十个米级旋回层序组成。

Several problems on the framework of stratigraphical sequences in craton basins, such as the recognization of Sander Rule, the concept of 'cycle within cycle' and so on,were discussed in this paper. In order to study the framework of stratigraphical sepuences in craton basins, the first step is to study 'meter-scale cycle sepuences' and their vertical stocking patterns. On the basis of this study, the lowfrequence cycle sequences are recognized and the framework of stratigraphical sequence of one outcrop section is reconstructed. The framework of the whole basin is constructed from one outcrop point to two dimensional space. In terms of this method, the authors studied stratigraphical sequences of Ordovician system in Wudang, Guiyang. The framework of stratigraphy from early to middle epoch of Ordovician in Wudang includes three sequences and six subsequences. And each subsequence contains in turn several tens parasequences (meter-scale cyclic sequence).