台湾海峡新生代沉积盆地的演化

台湾海峡新生代沉积盆地由厦澎、乌丘屿、新竹和台湾等坳陷组成。通过对海峡西部的地震地层特征和东部的新生代地层的分析和对比,结合沉积盆地的断裂构造、岩浆活动以及大地构造特征,认为该盆地的构造演化经历了中生代末地壳拉伸(孕育期)、晚白垩世—古新世张裂(幼年期)、始新世早期沉降(少年期)、始新世后期—渐新世再次张裂(青年期)、中新世早—中期冷却沉降(壮年期)、晚中新世—上新世早期挤压—收缩(老年期)、上新世后期—第四纪收缩—隆起(消亡期)。其中,孕育期—青年期为陆缘裂谷阶段,壮年期为构造调整阶段,老年期—消亡期为全面收缩及台湾坳陷封闭隆起阶段。台湾坳陷是陆缘裂谷从产生到衰亡的典型实例。

EVOLUTION OF CENOZOIC SEDIMENTARY BASIN IN TAIWAN STRAIT

The Cenozoic sedimentary basin of Taiwan Strait is composed of Xiapeng, Wuquyu, Xinzhu ,and Taiwan depressions. By analysis and correlation of seismic stratigraphic characteristics in the west part with Cenozoic strata in the east part of the strait, and combining with fault structures, magma-tism, tectonic characteristics of the basin, etc., it is suggested that the tectonic evolution of the basin has undergone crustal extension (pregnant period)at the end of Mesozoic, first extended rifting(in-fant period) in Late Cretaceous-Paleocene, tectonic subsidence (teenage period)in early Eocene, second extended rifting (youth period)in late Eocene-Oligocene, cooling subsidence (adult period) in early-middle Miocene, tectonic compression (old period) in late Miocene-early Pliocene, contrac-tion-uplft (dying period) in late Pliocene-Quaternary. Among the evolution cycles of the basin, pregnant period-youth period is a tectonic continental rifting stage, adult period is a tectonic rejust-ment stage, and old period-dying period is a stage of complete shortened and closed-uplift of Taiwan Depression. Taiwan Depression is a typical example for a continental margin rift from generation to dying.