摘要
南黄海盆地占据了下扬子板块的主体,自元古宙以来经历了多期构造运动,受到华北板块、扬子板块、华南板块、太平洋板块多个板块相互作用的影响,形成多期盆地演化阶段的叠合盆地。分析了南黄海盆地前人钻井资料及最新二维地震资料,并与下扬子苏北盆地地层及构造特征进行对比,认为整个下扬子区域受华北—扬子板块碰撞的影响,经历了中生代前陆盆地演化阶段。下扬子陆域部分地区发育相对完整的中生代沉积,记录了华北—扬子板块之间洋壳消减、陆陆碰撞、前陆盆地发育及碰撞后活动。而在下扬子对应海域延伸部分的南黄海盆地中,仅在盆地北部烟台坳陷东北缘通过钻井证实有侏罗纪前陆盆地地层,钻遇地层仅发育侏罗系上部陆相沉积,在地震剖面中可以解释出侏罗系下部海陆交互相地层,向上转变为陆相沉积地层。对比下扬子陆域与海域地层发育情况,华北—扬子板块碰撞造山过程对于下扬子整个区域的影响因地而异,在三叠纪末期—侏罗纪时期南黄海盆地内沉积缺失,南黄海海域区处于广泛抬升状态,印支运动期间地层挤压活动强烈,烟台坳陷内海相地层中逆冲断层广泛发育。在南黄海盆地东北缘,前陆盆地侏罗系地层发育于南倾边界断层的上盘,认为南黄海盆地侏罗纪前陆盆发育的构造背景受到同期北侧千里岩超高压变质带从深部折返影响,随着千里岩隆起带的快速抬升,为南黄海盆地北缘提供了沉积空间及物源,沉积了大套的侏罗系前陆盆地地层。
The southern Yellow Sea basin occupies the main part of the lower Yangtze plate. The basin had experienced multiphase deformation since the Proterozoic, led by tectonic interactions among the North China,Yangtze, and Pacific plates. The study utilized previous drilling and 2 D seismic data to compare the regional stratigraphic and structural framework. The lower Yangtze plate had experienced the North China-Yangtze collision, with the development of the Mesozoic foreland basin. Based on previous studies, the lower Yangtze region had developed a complete Mesozoic sequence and recorded the subduction of oceanic crust, continent collision,foreland basin development and post-collisional tectonics. While in the south Yellow Sea basin, the development of Jurassic foreland beasin was only confirmed in the northeastern sag, with its marine-terrigenous facies being interpreted in seismic sections. Stratigraphic comparison between the lower Yangtze terrestrial and marine areas revealed that the North China-Yangtze collision had different influence on different areas. During the Late Triassic-Jurassic,the southern Yellow Sea basin was likely denudated with thrust developed in the pelagic sequences. In the NE margin of the southern Yellow Sea basin, Jurassic foreland seqhence was developed in the hanging-wall of the south-dipping boundary fault. The Jurassic foreland development tectonics may have been affected by the exhumation of the Qianliyan high-pressure metamorphic belt from the deep crust. The rapid uplift of the Qianliyan belt likely provided the space and sediments for the Jurassic foreland deposition in the southern Yellow Sea basin.