ON THE SOUTH HUANGHAI SEA PERTAINING TO PALEOZOIC TO EARLY-MIDDLE TRIASSIC PALEOGEOGRAPHY, STRUCTURAL STYLE AND POTENTIAL HYDROCARBON TYPES

Abstract

Based on geological survey of the neighboring exposed areas (Korea and Jiangsu of China) and in- formation of several offshore boreholes, as well as investigation of islands of the South Huanghai (Yel- low) Sea, a set of paleogeographic schemes have been constructed. In terms of them the Paleozoic to Early-Middle Triassic configuration of the South Huanghai Sea basin is thus preliminarily analysed and approximate conditions of their lithologic character and lithofacies are thus supposed. The constrained relationship between four sedimentary tectonic development stages of the South Huang- hai Sea are illustrated. However, the author suggests that the Paleozoic to Early-Middle Triassic (Indo-China stage) tectonic level mostly belongs to the pregraben cycle of superposed basin of the South Huanghai Sea, and emphasizes late reworkings by other cycle. The pregraben tectonic level has a special structural style which in turn determines a variety of local structural patterns and trap types. In ad- dition to the need of further examination of distribution regularities of closures, the key of oil explora- tion is largely enhancing the study of sealing, reservoir and preservation conditions. As for the hydrocarbon generation of the Paleozoic to Early-Middle Triassic of the South Huanghai Sea, it appears not to be doubted. Nevertheless, wherever we find hydrocarbon accumulations it is critical and of the utmost im- portance to know how much scale it contains.