黔桂地区早泥盆世晚期碳稳定同位素变化及其对海平面变化的响应

The carbon isotope variation and its responses to sea level changes during the late Early Devonian period in Guizhou and Guangxi

摘要: 提要：对黔桂地区早泥盆世晚期不同相区典型剖面的沉积序列特征的分析显示，这一时期发生了两次明显的海平面升降变化过程，其沉积序列可识别出2个三级层序（SQ1、SQ2）并可进行区域对比；而广西象州下泥盆统大乐组碳稳定同位素的变化曲线与区域海平面变化曲线一致。表明海平面的变化不但控制了这一时期本区域的沉积序列，也深刻影响着这一时期的海水地球化学性质。

Abstract: Abstract: Based on the sedimentary sequence characteristics of the typical sections in different facies zones in Guizhou and Guangxi, the authors recognized two obvious sea level fluctuations during the late Early Devonian period. On such a basis, the sedimentary sequences are divided into two third grade sequences（SQ1, SQ2）. The sequences （SQ1, SQ2）can be correlated regionally. In addition, the authors observed that the curve of δ13C from Lower Devonian Dale Formation in Xiangzhou of Guangxi is coincident with the curve of the regional sea level fluctuations. This study indicates that the geochemistry as well as the sequences was well controlled by the sea level changes.