【摘要】 为了确定南海北部古俯冲带的具体位置,作者利用美国LCT综合反演软件对收集到的重磁数据进行处理解释,结果显示在南海北部从台湾西南部到一统暗沙隆起,即沿南海海盆北部陆坡为一条布格重力异常水平梯度峰值带,指示了古俯冲带的具体位置;其北部的高磁异常代表了与之对应的古火山弧。深反射地震资料也验证了南海北部陆坡位置存在古俯冲带,钻井资料显示俯冲带存在的时代为晚侏罗世到早白垩世。据此绘制了南海地区晚中生代到现今的构造古地理演化图,指出南海的扩张应与晚中生代俯冲带这个先存的软弱带有关,南海海盆正是从古俯冲带的位置开始扩张。更多还原

【Abstract】 To determine the exact location of the Mesozoic subduction zone in the northern South China Sea,the LCT joint inversion software is used to process gravity and magnetic data.The results show that there is a high horizontal-gradient of Bouguer gravity anomaly zone from southwestern Taiwan to the east of Yitongansha uplift,which may indicate the location of the ancient subduction,and there is a high magnetic anomaly zone parallel the gravity anomaly suggesting a Mesozoic volcanic arc which corresponds to the subduction.Well information proves that the subduction took place from the Late Jurassic to Early Cretaceous.Based on all above,we draw the tectonopaleogeographic evolution map of the South China Sea from Late Mesozoic to present day,and argue that the ancient subduction zone was a pre-existing weak band controlled the initial position of the spreading of the South China Sea oceanic basin.更多还原