华南晚二叠世碳酸盐岩碳同位素旋回对海平面变化的响应

The Carbon Isotope Cyclostratigraphic Responses to Sea Level Change in Upper Permian Limestones from South China

华南晚二叠世的碳同位素变化曲线是逐渐降低的，与全球海平面变化趋势相一致。华南晚二叠世碳酸盐岩碳同位素旋回可分为两个三级旋回，与两个三级海平面变化响应，其中吴家坪晚期和长兴期组成了一个三级旋回。华南长兴期识别出了三个四级碳同位素地层旋回可能与四级海平面变化旋回相对应。华南晚二叠世碳同位素旋回记录了全球海平面变化的信息：高值区和高海平面相对应，而低值区和低海平面相对应。

The carbon isotope shifts during Upper Permian in the South China drop gradually,and such phenomena may correspond to sea level change.There are two 3rd order cycle of carbon isotope stratigraphy of Late Permian.The early one is included in the lower and middle Wujiapingian Stage,while the late one is included in the upper Wujiapingian and Changhsingian Stage.The carbon isotope curve in Changhsingian of South China can be distinguished three 4th order cycles from late 3rd order cycle.It is considered that the limestones with high values of δ 13 C was deposited during highstand of sea level,while those with low values of δ 13 C was deposited at lowerstand of sea level.Therefore,the 3rd or 4th cycles of carbon isotope curve correspond to the 3rd or 4th order of sea level change,an interpretation supported by seqence stratigraphy analysis in South China.Based on carbon isotopic curve,the sea level dropped from Wujiapingian to Changhsingian,that is perfectly conincident with the strongest regressions of the end of Permian in the world.It may indicates that the carbon isotopic curves record the global sea level changes,and may suggests that sediments of the changhsingian limestones deposited in transgression induced by regional tectonic subsidence in South China.