Meticulous Depiction and Genetic Mechanism of Unconformity Belt Structure

Abstract

Current research on unconformity belt mainly concentrates on the analysis and description of unconformity surface and contact relationship with overlying and underlying strata. Too much emphasis on the division of the “three-layer structure” of unconformity yields obvious disadvantages, i.e., that studies are not only insufficient in the authenticity of architecture but also in the characterization of the combination of the two- and three-dimensional perspectives. Thus, the analysis of genetic mechanism and meticulous depiction is ignored. Accordingly, by making full use of the outcrops and combining previous research findings, this study aims to provide a detailed description and analysis for the unconformity belt structure, and points out the non-uniqueness of the three-layer structure of the unconformity belt. Based on the theory of depositional process and according to the method and principle of the “point-line-surface”, a comprehensive characterization method combined with a kind of “two-dimensional structure” and “three-dimensional structure” is proposed. A two-dimensional structure is a kind of surface structure, while the three-dimensional structure is a kind of body structure, Moreover, this study discusses the recognition significance of the visual unconformity line and visual unconformity surface with respect to the unconformity belt structure. According to the spatial allocation and geological significance of the unconformity belt, two types of models are established in order to depict the structure of unconformity belt better. Combined with the structural elements of the unconformity belt and complied from the viewpoint of the sedimentary environment, the formation mechanism of two-and three-dimensional structures is summarized.