南黄海北部航空重力场特征及主要地质认识

Characteristics of airborne gravity field and the main geological discovery in the northern South Yellow Sea

南黄海北部重力场信息丰富、梯级带发育、异常特征明显,充分反映了该区隆坳构造格局、断裂展布等地质特征。综合研究认为:NE向断裂构成了南黄海北部主体构造格架,嘉山—响水断裂、南黄海北缘断裂共同构成了苏鲁造山带南部边界;依据航空重磁资料新发现的NW向宫家岛深大断裂对南黄海北部基底构成、岩浆岩分布具有重要的控制作用;通过重磁联合反演,发现在南黄海北部坳陷的东北凹陷存在着前寒武系稳定的结晶基底;航空重力资料表明,胶莱盆地向东延伸进入南黄海,在海域内其最大沉积厚度可达3 km。上述地质认识和发现为南黄海北部海洋区域地质调查、油气资源调查及重大基础地质问题的解决提供了借鉴。

The obvious anomalies of gravity field in the northern South Yellow Sea distribute in a gradient belt form,which reflects the main geological characteristics of structural framework with uplifts,depressions and faults in this area. The main structural framework of South Yellow Sea consists of NE- trending faults,and Jiashan-Xiangshui fault belt and north margin of South Yellow Sea fault belt formed the south boundary of Su- Lu orogenic belt together. The aeromagnetic and gravity data indicate that the Gongjiadao NW- trending deep fault,a new discovery,controls basement formation and magmatic rocks distribution in the northern South Yellow Sea. The Precambrian crystalline basement exists in northeast sag of northern depression in the South Yellow Sea from inversion and interpretation of magnetic and gravity data. The aero gravity data indicate that Jiaolai basin extends eastward into South Yellow Sea with maximum thickness of deposition up to 3 km. These new recognition and discovery can provide some solutions for further investigation of marine regional geology,oil-gas investigation,and other fundamental geological problems in the northern South Yellow Sea.