FRACTURE CHARACTERISTICS AND BASIN EVOLUTION OF THE TAIXINAN BASIN IN CENOZOIC

Based on fault development characteristics and basin structure analyses,there are 3 evolution stages of the Taixinan Basin in Cenozoic.From Late Paleocene to Early Oligocene,rift-depression basin on continental margin is formed during the first stage.Grabens are controlled by border fractures.From Late Oligocene to Middle Miocene,marginal sea basin is formed during the second stage.The southern depression of the Taixinan Basin subsides quickly influenced by the South China Sea movement and becomes the subsidence and sedimentary center of the basin.However,the northern depression of the Taixinan Basin is an up-lift at the same time.From Late Miocene to Holocene,extension fractures generate along continental margin.As the oceanic crust of South China Sea dives below the Luzon Island arc along the Manila trench,new extension movement takes place along slope of the southern depre-ssion.The southern depression subsides quickly again and becomes deep sea basin at last.At the same time,the Philippines plate dives northwest,resulting in compressive tectonic movement from east to west in the east of the northern depression.The northern depression has become the sedimentary center of the Taixinan Basin.