摘要
基本层序是一段地层沉积特征的客观表现 ,可根据实际观察到的单层叠覆规律和界面特征来划分 ,不受其成因或环境解释的影响 ,根据其控制因素可分为旋回性基本层序 (包括自旋回性基本层序和他旋回性基本层序 )和非旋回性基本层序。野外应注重其顶底界面的识别。其垂向叠覆具有规律性变化特点 ,在层序发展不同阶段 ,基本层序的叠覆规律亦相应变化。基本层序不具级别意义 ,其规模受所描述的地层所控制。米级旋回的研究范围仅限于他旋回性基本层序发育的地层 ,两者为两套地层单位系统 (岩石地层单位和旋回地层单位 )的基本单元 ,不能等同视之。
Basic bed succession is a kind of sedimentary feature of a member of beds, which can be subdivided according to overlapping regularity of a bed and interfacial features, not influced by their genesis or forming environment On the basis of their controlling factors there are two kinds: cyclic basic bed succession (including auto cyclic and allo cyclic basic bed succession) and non cyclic basic bed succession In field, it should be paid more attention to the recognision on top and bottom interfaces In vertical, the overlapping is regular,and in different development stages, the overlapping regularity is varing In contrast,basic bed succession has no grade meaning, their scales are controlled by contained beds,ranging from centimeters to several ten meters; but meter grade cyclic is the product of high frequency sea level changing cycle, usually being several meters in thickness, which studied scope is only limited in the strata of allo cyclic basic bed succussion Both of them are basic units of two sets of stratigraphic unit systems: the former is a rock stratigraphic unit,but the latter is a cyclic stratigraphic Under some specific conditions, both of them problebly are the same, but the former emphases on the overlapping feature of strata, the latter on the cyclicity and environmental evolution
关键词
基本层序
米级旋回
地质调查
1:5万区调
basic bed sequence
meter grade cycle
verticle overlapping regularity
