扬子东南大陆边缘晚元古代—早古生代层序地层和盆地动力演化

扬子东南大陆边缘晚元古代－早古生代层序地层和盆地动力演化刘宝珺，许效松，徐强（成都地质矿产研究所）扬子板块早古生代的形成和演化对中国古大陆的板块构造演化有重大意义，本文试图通过用新发展起来的露头层序地层方法和沉积盆地演化分析来阐明其变化规律。在扬子板...

SEQUENCE STRATIGRAPHY AND BASIN DYNAMICS OF THE SOUTHEASTERN MARGIN OF THE YANGTZE PLATE IN SOUTH CHINA DURING THE LATE PROTEROZOIC TO EARLY PALAEOZOIC

The formation and evolution of the Yangtze plate play an important role in the tectonic evolution of China paleocontinent. This paper tries to demonstrate the evolution of the Yangtze Plate during the Early Palaeozoic with the aid of the method of outcrop sequence stratigraphy and sedimentary basin analysis. In the study of the palaeogeography of the Yangtze Plate,theoutcrop sequence stratigraphy has been developed, and this kind of new method provides a direct technigue to document the age and physical character of sequence boundaries and sea-levelchanges. In the first-order cycle of the eustatic changes in South China, the main sea-level riseexperienced two supercycles. In the Early Sinian, the melting of glaciers at two times led to theincrease in volume of the sea water and in depth of the sea water column,resulting in the firstmain rise of the sea level. The second supercycle is represented by the first and second EarlyCambrian sedimenntary sequences, indicating the maximum rate of the global sea-level rises andthe accomplishment of the largest transgression in South China. There occurred a progressivefall of sea level after the middle Late Cambrian, and the Early Palaeozoic first-order sea-levelvariation cycle was terminated at the end of the Silurian period.The detailed research on the sedimentation of the southeastern margin of the YangtzePlate, in combination with a lot of other geological data, has revealed that the evolution of thisarea in the Early Palaeozoic comprises the rifting in the Sinian, the thermal tectonic subsidenceof mature passive continental margin from Cambrian to Ordovician, and the foreland basinbending in the Silurian. The simulation of its tectonic subsidence and dynamics was done by theadvanced basin-analysis technique. Especially in the foreland basin, the dynamically quantitative simulation to that in old orogenic belts has been managed to be done and its quantitative parameters managed to be established using the advanced computer program for basin analysiswhich provides a new model to study the old orogenic belts in the world.