The eastern and western coastlines of the Yellow Sea are tortuous and there are many islands. Shandong Peninsula is a harbor-type sandy coast, while the coast of northern Jiangsu is a muddy coast. The main bays are Jiaozhou Bay and Haizhou Bay in the west, Korea Bay and Jianghua Bay in the east. The main islands are Changshan Islands and some islands on the west coast of the Korean Peninsula. The main rivers flowing into the Yellow Sea are Huaihe River, Yalu River and Datong River.
In the north (north of Haizhou Bay), slightly to the east, there is a long and narrow underwater depression (also known as the Yellow Sea Trough), which extends from Jeju Island to the Bohai Strait, and its depth gradually becomes shallow from south to north. The depression is steep in the east and gentle in the west. From the mouth of Yalu River to the mouth of Datong River in the north, there are a large number of tidal ridges with northeast trend, which constitute an important feature of submarine landform in the northern Yellow Sea. This is because the tidal range here is large and the tidal current is urgent, which leads to the formation of a "tidal ridge" parallel to the tidal current under the action of the tidal current. There are also wide underwater terraces on both sides of the Yellow Sea south of 38 north latitude. The west side is relatively complete, and there are cuts on the east side, and the distribution depth is inconsistent. There are large tidal ridges on the seabed in the south of the Yellow Sea. They were formed by long-term erosion of tidal current on the basis of the ancient Yellow River-ancient Yangtze River composite delta. The tidal ridges along the coast of northern Jiangsu are about 200 kilometers long from north to south and 90 kilometers wide from east to west. It consists of more than 70 sand bodies, distributed radially with Da Nang as the top. There are a series of small reefs in the south, such as Su Yan Reef, Duck Reef and Tiger Reef. They form an island reef line with Jeju Island, which is the natural dividing line between the Yellow Sea and the East China Sea.
geology
The surface sediments are terrigenous detritus, and there are residual sediments in some areas. From the coast to the ocean, sediments are distributed in strips from coarse to fine. Coastal areas are dominated by fine sand, with coarse debris such as gravel in the middle. Seabed sediments in the east mainly come from the Korean peninsula, and the west is the early input of the Yellow River and the Yangtze River. The deep water area in the middle is dominated by argillaceous fine-grained sediments, mainly from the Yellow River. There are silty sediments with different widths between coarse and fine sediments.
The basement of the Yellow Sea is composed of Precambrian metamorphic rock series. The northern part belongs to the Jiaoliao uplift belt of the Sino-Korean paraplatform, and the Tertiary period was basically in the uplift background. In the Cenozoic, the South Yellow Sea experienced a large-scale fault depression and received huge deposits. The main structural strike of the sea area is NNE direction, which consists of uplift zones and depression zones (basins) arranged in parallel. Jiaoliao uplift belt and South Yellow Sea-Subei depression belt constitute the structural framework of the Yellow Sea seabed, and its southeast edge extends into the East China Sea through Zhejiang-Fujian uplift belt. These uplift zones and depression zones become the basis and boundary conditions for the development of the Yellow Sea shelf. Since the late geological period, the Yellow River and the Yangtze River have brought abundant sediments, which have filled structural depressions, underwater valleys, tectonic uplift and underwater hills, thus forming a vast and flat continental shelf. Since the Quaternary, the glacial and interglacial periods have alternated, and the sea level has risen and fallen frequently, which has led to many landings and invasions of the continental shelf. The last transgression started from 2000 to 15000 years ago. About 6000 years ago, the sea level rose to its present position.
zone
The Yellow Sea is one of the marginal seas in the western Pacific Ocean. Its range starts from the mouth of the Yalu River in the north, south to the connecting line from Qidong corner on the north bank of the Yangtze River estuary to the southwest corner of Jeju Island in Korea, west to Liaodong Peninsula, Bohai Strait, Shandong Peninsula and the coast of northern Jiangsu, and east to the Korean Peninsula. Both the Yellow Sea and the Bohai Sea are shallow continental shelves, which collude with each other through the Bohai Strait. Most of the Yellow Sea is less than 60 meters deep. The seabed of the Yellow Sea is very gentle, and the slope of the inner edge of the continental shelf is greater than that of the outer edge, with an average slope of 0.0 1'2 1 ",which is slightly steeper than that of the Bohai Sea. The biggest feature of the seabed is that it inclines to the center from the west, north and east. The North Yellow Sea accounts for 1/6 of the total area of the Yellow Sea, with an average water depth of 38 meters. The South Yellow Sea accounts for 5/6 of the total area of the Yellow Sea, with an average water depth of 46 meters. The central Yellow Sea is a long and narrow underwater accumulation basin with a water depth of 50-80 meters. The bottom of the basin is flat, and there are depressions and uplifts with little height difference in some areas, but the slopes on both sides of the basin become steep, especially on the outer side of Shandong Peninsula. There are many hidden sand bars in the southern part of the Yellow Sea near the northern Jiangsu sea, and their shapes change rapidly. Except Haizhou Bay and Lianyungang-Changjiang Estuary, the coast of the Yellow Sea is silty and muddy, and the rest are bedrock and gravel coasts, especially the west coast of the Korean Peninsula, where there are many islands and headlands, which are staggered. The bays on the east coast of the Yellow Sea include West Korea Bay, Jianghua Bay and Gunsan Bay. The main bays on the west coast of the Yellow Sea are Rongcheng Bay, Sanggou Bay, Shidao Bay, Rushan Bay, Dingzi Bay, Jiaozhou Bay and Haizhou Bay. The main islands are Jeju Island, Gemini Island and Bailing Island in North Korea, with Lingshan Island and Dagong Island in the middle. The sea area between Jeju Island and Korean Peninsula is cheju strait, which is about 47 nautical miles wide from north to south. There are many islands in the north and few islands in the south, with a water depth of about 90 meters. The North Yellow Sea refers to the narrow sea surface in the north of the Yellow Sea. It is a semi-closed shallow sea basin surrounded by Jiaodong, Liaodong Peninsula and the northern part of the Korean Peninsula, with an area of 7 1.300 square kilometers. The inclination around the basin is more obvious than that in the Bohai Sea, slightly inclined to the south and the narrow part of the Yellow Sea, with an average inclination of 000' 44 "and an average water depth of 38 meters. The shallow water area of 45 meters accounts for more than half of the area of the North Yellow Sea, with a maximum depth of 85 meters, which is located on the southwest side of Pyongyang Island in North Korea. The central part of the North Yellow Sea is a muddy silt accumulation plain. In the northern part of the basin, there are underwater terraces inside and outside Changshan Island, with water depths of 20, 30, 40 and 50 meters, which are stepped down. Deep digging depressions often appear in the island or at the foot of the island. In the southwest of the basin is the sea cliff around Jiaodong Peninsula, on which is a 20-meter flat terrace buried by modern silt. To the end of Jiaodong Peninsula, two large and deep depressions appeared under the bank, which narrowed the terrace and increased the steepness, forming peripheral dams of deep depressions outside the bank slopes such as Chengshanjiao and Rongcheng Jiao. In the east of the basin is Xihan Bay, which is trapped along Bailing Island-Island-Yalu River. This is a sand ridge plain area, with parallel ridges, extending north-north-south-south-west. The farther you go to the top of the bay, the more divergent and narrow the sand ridges are, and the difference in water depth between ridges becomes smaller. The narrow part of the Yellow Sea under the cliff off Chengshanjiao is an underwater terrace of 60-75 meters, which is vertically penetrated by deep ditches (ancient rivers) along the coast of the Korean Peninsula and has a series of terraces. The submerged valley is covered with rocks and submarine protrusions of all levels. The South Yellow Sea covers an area of 309,400 square kilometers with an average slope of 0.0 50 ". The east side of the basin fluctuates obviously with a large slope, with an average slope of 01'40 ". There are submerged landforms and modern dynamic landforms on the seabed of the South Yellow Sea-deep troughs (ancient rivers or underwater valleys) on the continental margin. The deep trough on the continental margin runs through the north and south, and the water depth at the bottom is between 75 and 90 meters. There are obvious differences between the east and west sides of the valley. On the east side is the South Yellow Sea accumulation plain, covered with modern sand, with a flat bottom and a water depth of 60-80 meters. The east side of the accumulation plain is connected with the high cliff terrain, and there is an underwater terrace 200 kilometers long and 30 kilometers wide between the cliff and the coast. The back edge of terrace is connected with gentle underwater bank slope, and there are many islands on the underwater bank slope, which are cut and broken. Under the terrace 20 meters away from the coast, there are terraces 30 ~ 40 meters and 60 ~ 75 meters, which descend in steps. Several submerged valleys pass through the terraces and go straight into the water depth of 40 meters. The bottom of cheju strait is a submarine scouring trough, and the middle of the strait and its vicinity are alternately distributed with comb ridges and depressions, and the water depth is mostly between 1 10 ~ 125m. On both sides of the continental margin deep trough, there are two terraces of 20, 30 and 40 meters outward from Haizhou Bay, and the boundary line is roughly the extension line connecting Laoshan Tou-Da and Xiaohong Island-Lingshan Island. 20m terrace is wide 100km and covered with a thin layer of fine sand-silty sand. At the mouth of Jiaozhou Bay, the bedrock is exposed. The terrace of 30-40 meters is 200 kilometers wide, and the terrace fluctuates greatly. In addition to the terrace of 30-40 meters, there is also a terrace of 60-75 meters inclined to the muddy accumulation plain of the South Yellow Sea on the west side of the deep trough on the continental margin.
The Yellow Sea starts at 3140' north latitude, 39 50' north latitude,119 20' west longitude and126 50' east longitude. Its border with the East China Sea is the connecting line from Qidong Corner of Jiangsu Province to Jeju Island near the Korean Peninsula. Traditionally, the sea area north of the line from Jiao Shan at the eastern end of Shandong Peninsula to Bailing Island on the west coast of Korean Peninsula is called the North Yellow Sea, and the sea area south of it is called the South Yellow Sea. Geologically, the South Yellow Sea is located between Jiaoliao Block, Tanlu Fault and Fujian-Zhejiang Block, and consists of two Mesozoic-Cenozoic large basins that strike NEE. The Yellow Sea covers an area of about 400,000 square kilometers with an average water depth of 44 meters.
The coast of the Yellow Sea, except the section from Guanyun County, Jiangsu Province to the Yangtze River estuary, is a silty muddy coast, and the rest of the coast is a bedrock sandy coast. The coastline is tortuous, and there are many good ports in deep water. The main bays on the west coast of the Yellow Sea are Zhifu Bay (Yantai Port is in the bay, Dagujia River is the injection river), Jiaozhou Bay (Qingdao Port is famous in the bay, Dagu River is the injection river) and Haizhou Bay (Lianyungang is in the bay, Xinshu River and Rose River are the injection rivers).
Tectonic characteristics
(1) North Yellow Sea Structure The North Yellow Sea is similar to Jiaoliao Uplift and belongs to a long-term uplift area. Tectonic changes and magmatic activities have the same characteristics. The main structural lines are NE-trending and NE-trending, with no obvious folds, and large-scale NE-trending new faults extend into the sea. 1, Pingdu-Zhaoyuan fault in the west. It extends from Penglai Pavilion to the North Yellow Sea and is connected with Jinzhou Fault in Liaodong. There are large Linglong granite, Yanshanian granodiorite and a small amount of Cenozoic basalt along the fault zone. 2. Jimo-Mu Ping fault zone. It is composed of a series of NE-trending faults, which obviously control the deposition and development of the Laiyang Basin in Mesozoic. The fault zone may cross the North Yellow Sea and connect with the Yalu River fault. 3. Rushan-Rongcheng fault. It may cross the North Yellow Sea from Rongcheng and connect with the Linjin River fault in North Korea. There is a lot of Yanshanian granite activity along this fault. In recent years, the seismic exploration work carried out by China Petroleum Department in the western part of the North Yellow Sea has confirmed that the structure in the western part of the North Yellow Sea is an extension of Jiaoliao Uplift to the seabed. Wendeng Uplift in Jiaodong extends into the sea along the southern part of the North Yellow Sea, forming Liu Gongdao Uplift, which belongs to a long-term uplift structural unit and only accepts Tertiary and Quaternary sediments. The basement of the uplift is composed of pre-Sinian metamorphic rock series. The northern part of the North Yellow Sea is also a uplift structural unit, called the island uplift, which is an extension of the Dengshahe uplift in Liaodong to the sea. Between Liu Gongdao Uplift and Island Uplift is a faulted area, which is called the central fault zone. The central fault depression was caused by the local subsidence of extensional faults in Jiaoliao uplift, and the late Jurassic-Cretaceous sediments similar to Jiaolai sag were obviously developed in Mesozoic. By Tertiary, the scale and thickness of sediments gradually decreased. Obviously, the structural framework of Liang Long sag in the west of the North Yellow Sea has genetic connection and consistency with Jiaoliao area. Yanshan movement has a great influence on this area, and faults are developed, forming many fault basins. (2) South Yellow Sea Structure The South Yellow Sea belongs to the eastward extension of the Yangtze Platform and constitutes a large Mesozoic-Cenozoic sedimentary area in the South Yellow Sea. Geophysical data confirm that the development characteristics of structural faults in the South Yellow Sea can be roughly divided into three groups: NE direction, EW direction and NW direction. NE-trending faults are dominant in the area, which are consistent with the direction of regional tectonic lines, and often form the boundaries between uplift and depression, uplift and depression, which are characterized by large fault distance, long extension and long-term multiple activities. East-west faults are generally small in scale, short in fault distance and poor in continuity, which control secondary and local structures to some extent. The NW-trending fault is less developed and belongs to the secondary position. 1. Structural division: According to the current data, the South Yellow Sea area is divided into six structural units, namely: (1) Qianliyan uplift, which is distributed in the northern part of the South Yellow Sea and is an extension of Jiaodong uplift. The uplift basement is mainly composed of Jiaodong crystalline bedrock, lacking Paleozoic strata, and Mesozoic sediments and volcanic rocks only develop in the fault depression. In the south of the uplift, there is a rising bedrock uplift with a thickness of about 300 ~ 500 meters. Faults are developed in this uplift zone, including three groups of faults in the northeast, east and west, and ne-trending faults are dominant, such as Wu Shan-Ganyu fault and Rongcheng-Qingdao fault. (2) Northern depression: bounded by the deep fault zone at the southern margin of Qianliyan Uplift in the north, it is in fault contact with Qianliyan Uplift and extends eastward to the east of East longitude 124 line, with an area of 3.8 square kilometers. The background of magnetic field is wide, slow and calm negative anomaly, the buried depth of bedrock is about 1 ~ 5km, and gravity is reflected as parallel and staggered string negative anomaly zones. Seismic data show that the Mesozoic and Cenozoic strata are more than 4 kilometers thick. The northern depression can also be divided into two depression zones, north and south, and there is a middle uplift zone between the depression zones, and the tectonic line is mainly northeast. Seismic data show that the northern depression gradually dips from southwest to northeast, and the sedimentary layer thickens and the depression widens. The Cenozoic bottom interface is as deep as 4000 ~ 5000 meters, which has the conditions of oil generation and reservoir cap. (3) Central uplift: it is in fault contact with the northern depression, and it is an extension of Sulu uplift to the sea, with an east-west direction and an area of about 33,000 square kilometers. The geomagnetic field is characterized by large flat positive anomalies. The buried depth of magnetic bedrock is 6-7 kilometers, while the Cenozoic reflection interface is only 400-800 meters. It is speculated that the basement is composed of South Paleozoic and Mesozoic strata. (4) Southern depression: it is in fault or transitional relationship with northern uplift and southern Wunansha uplift, and it is connected with Dongtai depression in northern Jiangsu in the west, covering an area of about 28,000 square kilometers. The magnetic field background is a positive anomaly with a large increase, and gravity reflects the characteristics of low north-south and high middle. In general, the southern depression is a large dustpan-shaped fault depression, which is deep in the south and shallow in the north. The Cenozoic reflection surface in the depression is as deep as 4000 ~ 5000 meters. According to onshore drilling, the thickness of Sanduo Formation and Dai Nan Formation in the upper part of Eogene tends to be thinner from west to east. (5) Wunansha Uplift: generally east-west, and the northern part is in fault contact with the southern depression. Under the background of high gravity area and wide, gentle and calm negative magnetic field, the buried depth of magnetic basement is 3 ~ 4 kilometers. According to the onshore drilling data in southern Jiangsu, the uplift is mainly composed of Middle and Lower Triassic and Paleozoic. Seismic data show that the Paleogene strata in the uplift zone are missing, only in the low gravity area, and the upper tertiary Yancheng Formation and Quaternary strata are not thick. All the above uplift zones are covered by Neogene strata except the southern bedrock, and Paleogene strata are usually missing, and the Paleogene sedimentary center turns to the sea and tends to thicken. It can be seen that in the late Mesozoic, when the foundation stone was laid in the South Yellow Sea-Subei Depression, the Fujian-Lingnan uplift zone rose with it, and the seawater was blocked by the dam, making the South Yellow Sea basin a continental lake basin. In Tertiary, local seawater invaded, and the middle part of the uplift sank at the end of Tertiary, and seawater invaded the Yellow Sea in a large area. In the Pleistocene, the sea level rose and fell frequently, and the Yellow Sea experienced vicissitudes. 2. Faults and magmatic activities: The faults in the South Yellow Sea are well developed and can be roughly divided into three groups: NE-trending, EW-trending and NW-trending faults. Among them, NE-trending faults are dominant, which are consistent with the direction of regional tectonic lines, and often constitute the boundary between uplift and depression, uplift and depression structural units. It is characterized by long fault distance, long extension and long-term multiple activities. Gravity and magnetic earthquakes are reflected, which plays a major role in controlling Mesozoic and Cenozoic sediments. For example, Jiashan-Xiangshui-Qianliyan fault controls the southern bank boundary of Jiaodong Peninsula in geomorphology, and its tectonic position becomes the boundary between China-Korea platform and Yangtze platform, and also the boundary between Qianliyan uplift and headquarter depression. The EW-trending faults appear as fault groups locally, such as the obvious distribution between the northern depressions. Generally, the scale is small, the fault distance is not large, and the continuity is poor, which has certain control effect on the secondary local structure. The NW-trending faults are undeveloped and small in scale, and often appear in the form of staggered main faults. The South Yellow Sea suffered frequent Yanshan movement, accompanied by granite and intermediate-acid volcanic activity. The magnetic bodies along the NE-trending faults may be a reflection of Yanshanian magmatism. Seismic and drilling data reveal that the Cenozoic Himalayan movement in the South Yellow Sea was accompanied by two Himalayan basalt eruptions. To sum up, the South Yellow Sea has the following characteristics: (1) The South Yellow Sea belongs to the eastward extension of the Yangtze Platform and is a part of the whole basin from northern Jiangsu to the South Yellow Sea. The South Yellow Sea Basin began to appear in the Late Cretaceous, and its basement consists of Precambrian, Paleozoic and some Mesozoic (before Cretaceous). During the Silurian period, the eastern part of the basin uplifted and the sediments became thinner or missing. (2) The depression area of the South Yellow Sea Basin is vast, accounting for 765,438+0% of the basin area, and the Mesozoic and Cenozoic sediments are thick, which has the basic conditions for oil and gas formation and is a promising oil-bearing basin. (3) The NE-trending faults in the basin play a controlling role, and most depressions are dominated by faults. (4) The South Yellow Sea is a Mesozoic-Cenozoic basin formed since the late Yanshan period, which has experienced three development stages: fault depression, filling, depression deposition and overall depression.
Basement and caprock
(1) The North Yellow Sea and the North Yellow Sea belong to superimposed fault basins in the east of North China Platform. Jiaoliao Uplift in the west and Lin Lang Block in Korea and Pingnan Depression in the east. They extend to the bottom of the North Yellow Sea to varying degrees. According to the geological analysis around the Yellow Sea, the geological conditions of China and North Korea are similar, and they share the same basement. The basement lithology of Lin Lang block in the northern part of the Korean Peninsula is the same as that of Jiaoliao block, and they are all ancient metamorphic rock series, among which phyllite, shale, quartzite and limestone of xiang yuan system in Korea Proterozoic can be compared with that of China and North China in the late Proterozoic. The Cambrian strata are equivalent to the Cambrian strata in China (Cambrian and Ordovician strata are distributed in Shicheng Island and Hailin Island, located in the northeast of Shandong Province). There are sporadic early Paleozoic strata in Lin Lang block, Korea, and a set of platform-type sediments mainly composed of carbonate rocks and clastic rocks developed in Lower Paleozoic in Pingnan sag, Korea Group. Its lithofacies is the same as that of Paleozoic strata in North China, indicating that the Paleozoic geological development history of Pingnan Depression in North Korea is similar to that of North China platform syncline in China. The basement of the North Yellow Sea is mainly composed of metamorphic rocks such as Precambrian migmatite, gneiss, crystalline schist, marble and quartzite. Including North Korea's Anshan Group (Ar), Jiaodong Group (Ar-Pt), Fenzishan Group, Liaohe Group (Pt2), Penglai Group (Pt3), Wolin Group (Ar), Huanghai Group (PT 1 ~ 2) and Xiangyuan Group. It is covered with sporadic early Paleozoic strata, on which Mesozoic and Cenozoic sediments are formed. Therefore, the buried depth of the ancient basement in the North Yellow Sea may be shallow. Paleozoic sediments are mainly distributed in the northern and southern parts of the North Yellow Sea, Liaodong area and Pingnan area of Korea. They may belong to the same sedimentary area in the early Sinian, and they are terrigenous clastic deposits. Late Sinian Liaodong area is dominated by carbonate deposits, while Pingnan area is dominated by phyllite, shale and limestone deposits. From CAMBRIAN to Lower Ordovician, the above two areas were all shallow-sea carbonate deposits, which were uplifted, weathered and eroded for a long time after Middle Ordovician, and did not accept deposits. Devonian is composed of marine clastic rocks and carbonate rocks. From Middle Carboniferous to Permian, it was formed by clastic rocks alternating between land and sea. Since Jurassic, this area has entered a new stage of geological development, with strong fault activity and strong volcanic activity. During the Middle and Late Jurassic, many basins were formed in northern Liaodong, which were characterized by coal-bearing sandstone shale formation and volcanic rock formation. After the Upper Jurassic, it gradually moved southward, and the Jiaodong area was fractured, with strong volcanic activity, and terrigenous clastic rocks and volcanic rocks of the Upper Jurassic-Lower Cretaceous were deposited. There are terrigenous clastic rocks of late Jurassic Laiyang Formation (1000 ~ 4500m thick), early Cretaceous Qingshan Formation (6760m thick) and late Cretaceous clastic rocks, mudstone and limestone in Laiyang Basin, Jiaodong. There is a Jurassic Cretaceous basin composed of clastic rocks and coal measures strata in the south of Fuxian County, Liaodong. The Mesozoic strata in the northern part of the Korean peninsula can be compared with Jiaoliao and Jiaoliao areas. The lower Jurassic is sandstone shale coal-bearing strata, the middle Jurassic is volcanic rock accumulation, and the upper Jurassic strata are scattered. There are a series of Jurassic and Cretaceous basins in the northern part of the Korean peninsula, which obviously expand to the Yellow Sea. Triassic coal-bearing sandstone shale strata accumulated in Pingnan sag are covered by Jurassic pyroclastic rock series, indicating that there should be Mesozoic deposits in the North Yellow Sea. According to the aeromagnetic and comprehensive geophysical data of China in recent years, the geological conditions of the North Yellow Sea are similar to those of Liaodong Peninsula and Jiaodong Peninsula, and the sedimentary cover is not developed, only small basins isolated in Mesozoic and Cenozoic are distributed under the background of uplift structure. As the North Yellow Sea is a new basin, it was integrated with Jiaoliao in the early and middle period of Late Tertiary, and began to disintegrate and sink at the end of Late Tertiary, and was submerged by seawater to receive sediments. Although the sediments of Late Tertiary and Quaternary are widely distributed, the thickness is not large, and the distribution of Lower Tertiary is sporadic, with the characteristics of small thickness. (2) The South Yellow Sea, Hainan and the Yellow Sea belong to the east of the Yangtze Platform Fold Belt under the Yangtze Platform. Qianliyan uplift in the coastal waters of Shandong Peninsula in the north belongs to Jiaodong shield of North China Platform. They are bounded by deep faults in the southern margin of Qianliyan uplift. The east of 124 E may belong to the Gyeonggi-do block on the Korean Peninsula, which is an extension of Wochuan Depression in the sea. The main body of the South Yellow Sea Basin is a Mesozoic-Cenozoic depression superimposed on the Yangtze platform. The southwest is connected with Subei depression, forming a unified Subei-South Yellow Sea depression belt. The aeromagnetic results show that there is an ancient and hard magnetic block in the basement of the South Yellow Sea in the middle of the sea area, which shows a positive anomaly of the block with slowly changing magnetic field width. It is composed of several magnetic crystalline rocks with different sizes and trends. The distribution of rocks is chaotic and the strike is complex, mainly in the east-west, northwest, northwest and northeast directions. In the regional magnetic field, they all show positive anomalies with uncertain shapes and slowly changing widths. Obviously, they represent the core of the crystalline complex that experienced highly migmatization and granitization, and constitute the main body of the crystalline block in the Yellow Sea. Aeromagnetism also shows that the crystalline basement of the whole South Yellow Sea is heterogeneous, indicating that it is an extension of different structural basements in the surrounding land. The northern part of Qianliyan Uplift is similar to the middle-shallow metamorphic rock series composed of gneiss, schist, granulite and marble in Jiaonan Group of Jiaonan Uplift and the basement rock series composed of gneiss, schist, migmatite, mixed granite and granulite in Jiaodong Group of Wendeng Uplift. The western part is similar to the basement rock series composed of metamorphic rocks, gneiss, quartzite, marble, metamorphic rock series with strong local migmatization and shallow metamorphic rock series such as phosphorite, schist, granulite and granulite of Haizhou Group exposed near Lianyungang in northern Jiangsu. The massive anomaly of Wunansha Uplift in the south is replaced by the positive and negative anomaly of NE direction, which is supposed to be the reflection of Shangbanxi Group in Shanghai Uplift. The magnetic anomaly in the southeast changes rapidly, and it is speculated that it has entered the ∞ zone of Fujian-Lingnan uplift, which is a comprehensive reflection of the pre-Devonian metamorphic basement uplift and Mesozoic igneous rocks. The Jinning movement at the end of late Proterozoic formed a unified metamorphic crystalline basement. According to the comprehensive geophysical interpretation and geological data of the land, the caprock in the South Yellow Sea can be roughly divided into three structural layers: 1 and the lower structural layer. From the structural relationship, it is composed of Sinian-Lower and Middle Triassic in the Yangtze River, which is similar to the lower Yangtze area. From Sinian to Silurian, the lower part is clastic rock formation (lower part of Sinian), the middle part is carbonate rock formation (upper part of Sinian-Ordovician), and the upper part is graptolite shale and sand shale formation (Silurian). Devonian-Lower Carboniferous, the lower part is continental Wu Tong timely sandstone, and the upper part is lower Carboniferous shallow sea limestone and coastal sandstone. The Middle Carboniferous-Middle Triassic is basically carbonate rock formation and coal-bearing strata (Longtan coal measures in late Permian). The Indosinian movement in the late Middle Triassic led to the unified fold of the lower structural layer. After the end of Indosinian Movement, the South Yellow Sea ended the marine immersion environment and accepted continental deposits instead. Strong faults and folds occurred in Yanshan movement, accompanied by volcanic activity, resulting in uplift and depression, which laid the foundation for the formation and development of Mesozoic and Cenozoic basins. The Jurassic system is mainly composed of river and lake clastic deposits, which are thick in the south and thin in the north; The early Cretaceous was basically a freshwater river and lake facies deposit, containing a small amount of volcanic rocks; In the late Cretaceous, the whole basin sank. Except for some anticlinorium, the red clasts of Pukou Formation and Chishan Formation are deposited in different parts. 2. Meso-structural layer: After Yanshan movement, the middle part of the South Yellow Sea rose, and depressions were formed on the north and south sides respectively, forming a Cenozoic sedimentary center, forming a continuous deposition of Late Cretaceous and Paleogene. The lower part of Taizhou Formation of Upper Cretaceous is fluvial sand mudstone mixed with black mudstone, and the upper part is fluvial black mudstone mixed with brown red sand mudstone, which is one of the source rocks in South Yellow Sea Basin. The Eocene Funing Formation of Eogene is composed of dark mudstone, oil shale, carbonaceous shale mixed with sand mudstone, gypsum and thin limestone in fluvial facies and coastal lake facies, which is a good source rock and reservoir rock. The Oligocene Dai Nan Formation consists of dark gray mudstone, glutenite mixed with lacustrine carbonaceous shale, thin coal seam, brownish red mudstone and sandstone. The upper part of Sanduo Formation is a good reservoir, which is composed of fluvial brownish red mudstone mixed with glutenite, black mudstone and thin oil shale. After the Triassic Sanduo Formation was deposited, Triassic movement occurred, resulting in the unconformity between the Upper and Lower Tertiary. Paleogene suffered from folds and faults, and finally the whole area was exposed to water and eroded. 3. Upper structural layer: equivalent to Pliocene Yancheng Formation and Quaternary Dongtai Formation. After the Sanduo movement, the tectonic activity gradually weakened, and the fault activity that controlled the development of the basin was replaced by regional recession. Yancheng Formation and Dongtai Formation are distributed in the whole region, with nearly horizontal occurrence, mainly occurring in sandstone and mudstone of fluvial facies and lacustrine facies. Seawater immersion began in Quaternary, with transitional phase between land and sea in the early stage and detrital deposition in coastal shallow sea in the later stage.