华南陆缘晚三叠-早、中侏罗世海平面相对升降与古气候演化的地球化学记录

The Geochemistry Records of Sea-Level Relative Movement and Paleoclimatic Evolution of the South China Continental Margin in Late Triassic-Early-Middle Jurassic

晚三叠-中侏罗世华南陆缘发生多期海侵-海退旋回.元素地球化学特征指示的古盐度高低和古水深深浅记录了海平面的相对升降.华南陆缘存在3个级别的海平面变化.其中,Ⅲ级海平面波动频繁,由晚三叠世3次波动、早侏罗世4次波动和早、中侏罗世2次波动构成了此间大规模海侵-海退旋回.华南陆缘Ⅰ级海平面相对升降曲线与全球海平面长周期曲线,在诺利克阶早期-辛涅缪尔阶晚期变化同步,在辛涅缪尔阶晚期-阿连阶变化相悖.Ⅲ级海平面相对升降曲线与全球海平面短周期曲线,在瑞替阶-辛涅缪尔阶晚期同发生4次波动,时间上近乎同步.Sr/Cu值指示的元素迁移与富集反映了气候的温湿与干热.粤中-粤东地区晚三叠-早、中侏罗世经历了温湿-干热-温湿的气候变化.

The margin of South China in Late Triassic-Middle Jurassic had undergone multi transgression-regression cycles.The element geochemistry character indicates the paleosalinity and the water depth records the relative movements of the sea level.There are three levels of sea level change in the margin of South China.The grade III sea-level fluctuated frequently.There were 3 times in Late Triassic,4 times in Early Jurassic and 2 times in Early or Middle Jurassic.These fluctuations constituted a large-scale transgression-regression cycle.The relative movements curve of the grade I sea-level is synchronous with the change of the long-period global sea-level curve in early Norian-late Sinemurian of the margin of South China.But it is contrary in late Sinemurian-Aalenian.The relative movements curve of the grade III sea-level and the short-period global sea-level curve occurred 4 fluctuations in Rhaetian-late Sinemurian.And they were almost simultaneously in time.The element migration and enrichment which were indicated by Sr/Cu reflected the warm-humid and dry-heat of the climate.The area of Middle Guangdong-East Guangdong in Late Triassic-Early-Middle Jurassic undergone the climate change of warm-humid to dry-heat and to warm-humid.