【作者】 杨金玉；

【导师】 徐世浙； 张训华；

【作者基本信息】 浙江大学 ， 地球探测与信息技术， 2010， 博士

【摘要】 南黄海盆地位于扬子块体东段,是下扬子块体向海域的延伸部分。南黄海盆地是一个大型海相中、古生代和陆相中、新生代的叠合盆地。40多年来,南黄海的油气地质勘探主要针对陆相中、新生代盆地,但并未获得油气突破。近年来,南黄海海域海相中、古生界作为一个新的勘探领域越来越得到重视,国家加大了针对这一层系的调查工作量,青岛海洋地质研究所通过南通幅区域地质调查(2002-2006)以及南黄海前第三系油气战略选区项目(2005-2009)分别实施了1727.5 km和3200 km的多道地震测量,同时获取了3000多公里的重、磁资料。本文的研究是在前人取得的地质认识的基础上,利用这些最新地震和重、磁资料,采用综合地质、地球物理的方法探讨南黄海盆地及周边区域构造地质问题,划分了盆地海相中、古生代地层层序,分析了海相中、古生界分布和构造特征,并讨论了中、古生代盆地的构造演化。最新的基于位场分离和迭代法向下大深度延拓的视密度反演的技术被应用于重力数据的处理,并主要用于厘定区内深大断裂,如块体间的边界断层和其它重要地质界线的延伸。通过重力和磁力数据的转换处理分析,解释了研究区内断裂和火成岩的平面分布。利用最新的地震资料结合钻井标定和海陆对比的方法划分了海相中、古生界的地震地层层序,并采用2.5D重、磁、震联合反演拟合技术验证了剖面上地层分布。利用地震资料解释成果得到了海相中、古生界顶面(印支面)的深度信息,通过利用单一界面的3D反演法推算了中、古生界底面的深度,并编制了中生界三叠系青龙灰岩的残留厚度图以及上古生界二叠系的残留厚度图,从而了解了海相中、古生代地层的分布和构造特征。本文认为扬子块体与中朝块体之间的结合带为苏胶-京畿造山带,嘉山-泗洪-连云港断裂以及海域的千里岩北缘断裂是扬子与苏胶造山带的边界断层。扬子与华南的边界断裂为江山-绍兴-光州断裂,NE向和EW向为构造主控方向,扬子块体向东不仅包括南黄海,还包括朝鲜半岛中部,但范围比较局限。南黄海盆地是下扬子的主体,具有古老的稳定的陆核,因此虽然所处构造环境复杂,经历了复杂的构造运动,其构造稳定性依然好于周边地区,受火山岩浆活动影响较小,有利于海相地层的保存。苏北—南黄海盆地是一个整体,具有较完整的加里东期、海西期以及印支期海相层序,基底为太古界—元古界变质岩系。盆地发育分为原型沉积为主和后期改造为主两大构造阶段,震旦纪至早三叠纪为海相原型盆地沉积时期；晚三叠世至第四纪为海相中、古生界盆地的主要改造时期。盆地自北向南划分为北部坳陷、中部隆起、南部坳陷、勿南沙隆起等五个喜山期构造单元。海相中、古生界的构造格局仍为两坳一隆,与新生代构造格局相似,但具体位置和构造方向有所不同。中、古生界底面深度在4-13km之间变化,平均埋深约8km。海相中古生界厚度分布主要受基底起伏控制,但厚度曲线整体上NE的走向也体现出印支运动造成的影响,中部隆起区中、古生界沉积厚度变化比较稳定。震旦-下二叠统广泛分布,其中震旦-志留系分布厚度稳定,泥盆-下二叠统分布厚度变化较大；三叠系下统青龙组和二叠系上统的大隆组和龙潭组在南黄海盆地南部坳陷和勿南沙隆起分布广泛,北部坳陷分布局限,在中部隆起上已基本剥蚀贻尽。限于目前的资料,还难以得知下古生界具体残留的厚度。更多还原

【Abstract】 The South Yellow Sea basin is located on the east of the Yangtze block. It is the extension of lower Yangtze block in the Yellow Sea. The South Yellow Sea basin is a huge superposed basin composed of Paleo-Mesozoic marine facies basin and Meso-Cenozoic terringenous sedimentary basin. In the past forty years, the petroleum geological exploration has aimed at Meso-Cenozoic terringenous sedimentary basin, but there was no breakthrough of industrial oil and gas discoverer yet. In recent years, the Pale-Mesozoic marine facies basin has been paid more and more attention as a new hydrocarbon exploration target. In resent years, geophysical survey aiming at these potential strata in the South Yellow Sea has been implemented by Qingdao Institute of Marine Geology. The marine regional geological survey of Nantong sheet in the South Yellow Sea (2002-2006) finished 1727.5 km seismic survey. The Pre-Tertiay hydrocarbon stratege survey in the South Yellow Sea project (2005-2009) carried out 3200 km seismic measurement, and more than 3000 km gravity and magnetic data had been acquired at the same time. Based on previous research result and the new seismic, gravity and magnetic data, this paper analyzed the tectonic framework of the South Yellow Sea basin and its adjacent area, divided the stratigraphic sequence, discussed the distribution and structure characteristic of Paleo-Mesozoic marine strata and the evolution process of marine Paleo-Mesozoic basin. The integrated geological and geophysical interpretation method was used in the research.A new apparent density inversion technology based on potential field separation and downward continuation in a large distance using iteration method was used in gravity data processing. The result helped to locate the position of the deep major fault, especially the extension of the block boundary fault and the other important geological boundary. The distribution of the faults and volcanic rocks were analyzed by gravity and magnetic data interpretation. New seismic data interpretation combined with the drilling data and geological correlation between land and sea were used to classify the marine Paleo-Mesozoic stratigraphic sequence. Geologic models of two profiles were rectified by 2.5D gravity, magnetic and seismic joint inversion and modeling. The depth of top surface of the marine Paleo-Mesozoic strata was got by seismic interpretation; undulation of the bottom surface was derived by 3D magnetic inversion. The residual thickness map of Triassic Qinglong limestone and Permian strata was also drawn in order to understand the distribution and structure feature of the marine Paleo-Mesozoic strata.In this paper, the junction zone in between the Yangtze massif and Sino-Korea massif was defined as Sujiao-Gyeonggi orogenic belt. Jiashan-Sihong-Lianyungang fault and the fault at north edge of Qianliyan in the sea was the boundary fault between Yangtze block and Sujiao orogenic belt. Jiangshan-Shaoxing-Kongju fault was delimitated as the boundary fault between Yangtze and South China massif. The dominant tectonic structures trend was in NE and EW direction. To the east, the Yangtze block not only includeed the South Yellow Sea, but also a small part in the central Korea Peninsula. The South Yellow Sea basin was the main part of the Lower Yangtze block, its stable Archean nucleus was beneficial to minimize the influence of tectonic movement. Thus the Yellow Sea basin was comparatively more stable than the adjacent area even though its tectonic environment was complicated and endured several tectonic movements. The volcanic and magma activities in the basin were general small scales, and which favored the preservation of the marine Paleo-Mesozoic strata.The Subei basin and the South Yellow Sea basin were an integral basin. It developed integrate Caledonian-Hercynian-Indosinian marine sequences. The basement was composed of Archean and Proterozoic metamorphic rocks. The basin developed two main tectonic stages:the prototype deposition and the late deformation. The prototype deposition stage started from Sinian and finished in the early Triassic. During the late Triassic and Quaternary, the basin had been transformed by tectonic movements. The basin could be divided into five Himalayan tectonic units, the northern depression, the central uplift, the southern depression and Wunansha uplift. The tectonic framework of marine Pale-Mesozoic strata was similar to that of the Himalayan, it also could be divided into two depressions and one uplift. But the position and trend of the units were different. The depth of the bottom surface of Paleo-Mesozoic marine strata varied from 4-13 km, the average depth was 8km. The thickness of the marine sequence was mainly controlled by the undulation of the basement, but the influence of the Indosinian movement can also be seen by the northeast-trending isopachous line. The thickness of the marine Paleo-Mesozoic strata was comparatively stable in the central uplift. The Sinian-lower Permian strata were widely spread in the basin, and the Sinian-Silurian strata had stable distribution. The distribution and thickness Devonian-lower Permian strata varied much in different area. The lower Triassic Qinglong formation and the upper Permian Dalong and Longtan formation were widely distributed in the southern depression and Wunansha Uplift of the South Yellow Sea basin, the distribution of this sequence in the northern depression was very limited, in the central uplift, few had been left due to the combined effect of uplift and denudation. At present, the residual thickness of the lower Paleozoic was still unknown due to the limited data.更多还原