从地层记录的特性论岩石地层学的困惑

地层记录有四个特性:不完整性、非渐变性、旋回性及复杂性。这四个特性在岩石地层中将形成两种穿时性——相界面穿时及间断面穿时,最终造成常规标志层的缺乏和复杂有序的相变。为此,根据"岩性、岩相的统一"来划分和对比岩石地层单位时,常常具有人为性及不确定性。在相序基础上识别出的旋回层序,具有空间上相序的有序性及时间上环境变化的同步性两大特征,在把它用于岩石地层学研究时,具有以下优点:1)不同级别旋回层序及其有序叠加形式的研究是从岩石地层记录的复杂性中寻找规律的最好方法;2)旋回层序,特别是长周期旋回层序的界面,同样可以作为岩石地层单位的界面;3)地层记录的旋回性的研究,可以丰富岩石地层单位的的内容,为其划分对比提供更多的天然标志。

Discussion on the perlexity in lithostratigraphy in terms of the particularity of stratigraphical records

The particularity of stratigraphical records includes non-integrity,nature of non-gradual change,cyclicity and complexity.Two kinds of diachrononism that are di- achrononism of facies-change surface and the one of punctuacted surface will be pro- duced by these four particularities,which lead to the lack of mark-unit and the diversity of facies-change in lithostratigraphy.So the non-fixity and artificial conclusion are al- way caused on division and correlation of lithostrata in terms of"the integrity of litholo- gy as well as lithofacies". For cyclic-sequences that are discerned on the basis of facies-succession there are two stratigraphically meaningful characters,i,e.the regularity of lithofacies-succession in space and the simultanity of environmental change in time.Based on cyclic-sequences, the following merits for the study of lithostratigraphy may be obtained:1)in order to get more regularity from the complexity of stratigraphical records,the useful method is to discern the cyclic-sequences of various orders and their regularly stacking patterns 2)the surface of cyclic-sequence,especially long-term cyclic-sequence,may be applied to dividing surface of lithostratigraphical units;3)the study of cyclic records of strata may improve the precision of lithostratigraphical units and provide avaiable natural marks for division and correlation of lithostrata.