摘要： 提出岩相古地理研究的优势相思路与方法,优势相划分由等时性界面限定的沉积持续时间和沉积厚度这条主线串联起来。优势相分析具有定性与定量兼有的特征,即以各种定性与定量的、反映某个时期或阶段沉积环境特点的关键因素或指标资料为基础,由点到线、由线到面,点、线、面结合,由二维到三维空间,确定该阶段或该时期占优势的主导沉积相或岩相。主导沉积相或岩相既要满足沉积持续时间的主导、又要满足沉积物质表现优势,还需满足盆地或区块总体背景和环境格局上的合理性与综合性。指出优势因素(或称优势参数)是优势相确定的基础和前提。提出了“广义岩相古地理”和“狭义岩相古地理”2个概念,在其研究内容、精度、理论深度、研究区域范围和应用等方面进行区别,但并不能由一两个指标就简单区分,需要综合对比和分析才可以界定。论文还论述了岩相古地理研究出现的7个新方向,这些新的研究方向可根据研究目的和解决的实际勘探目标,进行广义和狭义岩相古地理分析。运用优势相分析思路和方法,在柴达木盆地新生代等时性地层划分及建立了盆地等时地层格架基础上,进行了柴达木盆地关键时期岩相古地理恢复。

关键词: 优势相方法, 优势因素, 主导指标, 广义岩相古地理, 狭义岩相古地理, 柴达木盆地

Abstract: This paper puts forward the idea and method of dominant facies in the research of lithofacies palaeogeography. The dominant facies division is connected by the depositional duration and depositional thickness,which are confined by isochronous interface. The dominant facies analysis shows both qualitative and quantitative characteristics. In other words,based on various qualitative and quantitative key factors or index data that reflect the characteristics of sedimentary environment in a certain period or stage,using the workflow from point to line,line to plane,two dimensions to three dimensions,the dominant sedimentary facies or lithofacies of the aimed stage or period are determined. The dominant sedimentary facies or lithofacies should provide the dominance of sedimentary duration,show the superiority of sedimentary material expression,and demonstrate the rationality and comprehensiveness of the overall background and environmental pattern of the basin or block. It is pointed out that the dominant factor(or the dominant parameter)is the basis and premise of determining the dominant facies. In this paper,concepts of lithofacies palaeogeography are divided into the broad sense and the narrow sense which are based on the aspects of research content,accuracy,theory depth,research area and application. However,the differences between these two concepts can only be distinguished by comprehensive comparison and analysis,rather than by one or two indicators. This paper also discusses seven newly emerged directions of lithofacies palaeogeography research,such as sequence stratigraphy-lithofacies palaeogeography,tectonic-lithofacies palaeogeography,quantitative lithofacies palaeogeography,biology-lithofacies palaeogeography,coal forming lithofacies palaeogeography,reservoir lithofacies palaeogeography,etc.,which show distinctive characteristics and are an important development of lithofacies palaeogeography. These new research directions can be used to analyze lithofacies palaeogeography in both broad and narrow sense according to the research purpose and the actual exploration target. Based on the division of Cenozoic isochronous strata and the establishment of isochronous stratigraphic framework,the lithofacies palaeogeography of Qaidam Basin in the key period has been restored by using the idea and method of dominant facies analysis.

Key words: method of dominant facies, advantage factor, dominant parameter, lithofacies palaeogeography in broad sense, lithofacies palaeogeography in narrow sense, Qaidam Basin

中图分类号: 

• P512.2