The southeastern coastal region of South China, as an important part of the East Asian Continental Margin (EACM), was once the leading contact zone of the Paleo-Pacific subduction zone during the Late Mesozoic, resulting in a complex system of faults and tectonic blocks. However, the paleoposition and tectonic relationship between the Pingtan-Dongshan Belt (PDB) and the stable part of the South China Block (SCB) remain unclear, hindering our understanding of the evolution history of the SCB at its southeastern margin, as well as the tectonic attributes of the EACM. This paper presents Early Cretaceous paleomagnetic results for the PDB and the adjacent Southeast Coast Magmatic Belt (SCMB) in South China, with the primary objective of constraining the paleopositions of these two belts. The mean directions of the characteristic remanent magnetization (ChRM) of the PDB and SCMB exhibit intrinsic consistency, with a combined mean direction of D/I = 8.0°/51.1°, κ = 49.5, and α95 = 6.6°. The corresponding paleomagnetic pole is at 80.0°N, 162.7°E, and A95 = 7.9°, which is consistent with the Early Cretaceous Eurasia paleomagnetic reference pole at the 95% confidence level. These results confirm the tectonic stability of the eastern margin of the SCB throughout the Cretaceous period, with the extent of the SCB's stable domain extending eastward to encompass the coastal regions of South China. The PDB was tectonically coupled with the broader SCB and subjected to Paleo-Pacific Plate subduction, causing the widespread ductile shear deformation observed across the PDB and adjacent areas.

The East China Sea Basin (ECSB), a critical component of the continental margin basin system and the continental mosaic framework in the western Pacific, remains subject to ongoing debates on its origin and kinematics. Current academic debates regarding the tectonic affinity of the East China Sea (ECS) involve two contrasting interpretations: whether it is "part of the South China Block" or "an exotic microcontinent". Focusing on this issue, this study presents the first systematic paleomagnetic investigation of core samples from nine boreholes within the ECSB, establishing a paleomagnetic composite section spanning the Early Cretaceous (similar to 135 Ma) to middle Eocene (similar to 40 Ma). Quantitative analysis of paleolatitudes reveals that the ECS occupied low-latitude positions (20 degrees N-25 degrees N) similar to those of the SCB throughout similar to 135 - similar to 40 Ma. The history of relative motion between these two blocks reveals a two-stage kinematic process: (1) In 130 - 65 Ma, there is little latitudinal migration with no significant relative movement; (2) In 65 - 40 Ma, the ECS moved rapidly northward and showed a potential left-lateral movement relative to the SCB. Regardless of the scale of relative movement and whether it existed, the close paleolatitudes and similar rotational orientations indicate that, at least since the Paleocene, the ECS has exhibited a close paleogeographic affinity with SCB. Integrated analysis of eastward migration patterns in sedimentary depocenters and magmatic arcs within the basin suggests that the kinematic evolution and basin development of the ECS were principally driven by oblique subduction and slab rollback of the (Paleo-)Pacific Plate.

Tectonic plate drift, a major force driving Earth's geological history, governs the opening and closing of ocean basins, the breakup and assembly of supercontinents, and the formation of sedimentary basins. Recent geological, geophysical, and experimental evidence further suggests that plate drift velocity influences the geometry of slabs, the timing of large igneous province volcanism, and the chemical properties of oceanic rocks. While these studies have yielded significant academic insights, the direct impact of plate drift velocity on hydrocarbon resource development remains poorly understood, and relevant research is limited. This study is based on the latest Palaeozoic global plate reconstructions and previously published data on major Palaeozoic hydrocarbon source rocks. By comparing variations in the global plate drift velocity with the quantities and total organic carbon (TOC) contents of different types of hydrocarbon source rocks, we demonstrate the significant impact of plate drift velocity on hydrocarbon source rock development. Our results indicate that low plate drift velocities (0.97-5.00 cm/yr) provided the most favourable conditions for hydrocarbon source rock formation. Medium velocities (5.00-10.00 cm/yr) were moderately favourable, whereas high velocities (10.00-12.76 cm/yr) were relatively unfavourable. Furthermore, under low drift velocities, when plates were located at palaeolatitudes of 15-30°N/S and exhibited high stability, conditions were most conducive to high-abundance hydrocarbon source rock formation. These findings underscore the critical role of plate drift velocity in controlling hydrocarbon source rock development and provide a new perspective and approach for global hydrocarbon exploration and resource assessment.

The East China Sea Shelf Basin (ECSSB), an important part of the western Pacific margin, is located in a key area of subduction and coupling of the western Pacific/East Asian continent. There are many unknowns regarding the basin structure and formation mechanism. There are three different viewpoints on the driving mechanism of the tectonic transition at 43 Ma: the India-Eurasia Plate hard collision, the subduction direction change in the western Pacific Plate, and the joint action of the western Pacific Plate and Philippine Sea Plate movements. To address this controversy, we use the SHELLS modeling method to simulate the tectonic stress field of the Pingbei area (PBA) under the constraints of paleofaults, paleotopography, paleoheat flow, petrophysical parameters, and different tectonic boundary conditions during two critical periods: before and after 43 Ma. The modeling results that most closely match the observations are as follows: at 43 Ma, the boundary extension direction changed from NW-SE to NNW-SSE, and the extension rate changed from 0.16 similar to 0.52 mm/a to 0.15 similar to 0.24 mm/a. Based on analysis of the coupling relationship between stress field simulation results and the formation of peripheral plates in the region, we believe that the driving mechanism of the 43 Ma tectonic transition in the ECSSB and western Pacific/Southeast Asia region is mainly due to changes in the retreat direction of the western Pacific Plate and the extension direction and velocity of the study area, combined with the northward movement of the Philippine Sea Plate.

The pressing need to balance groundwater demand with environmental protection has driven the development of ecological compensation mechanisms in urban areas. However, current representations of environmental damage from groundwater exploitation are not intuitive, and existing compensation calculation methods are simplistic and unverified. This paper proposes an urban-scale groundwater ecological compensation assessment model based on emergy theory. This model aims to comprehensively consider the environmental impacts of groundwater exploitation and establish a reasonable ecological compensation standard. By introducing emergy theory, the ecosystem loss due to groundwater exploitation can be more accurately assessed, providing a scientific basis for sustainable groundwater resource utilization. The results show that from 2001 to 2020, the total emergy loss caused by groundwater exploitation in 192 cities was 9.75×1023sej, with a slow decreasing trend over time. The total groundwater ecological compensation amount was 1.79´1011$, showing a gradual increasing trend. Comparison with existing quotas in 21 cities demonstrates the strong reliability of the calculated compensation standards. Under the proposed standards, implementing targeted water-saving policies and projects could reduce groundwater extraction by 2.43´1011 m3. These findings offer a robust framework for sustainable groundwater management, providing valuable insights for policymakers to enhance water resource conservation and ecological protection.

Containing representative shale gas reservoirs, the Wufeng-Longmaxi Formations in the Nanchuan region in South China have been modified by three compressional tectonic movements (in the Late Jurassic to Early Cretaceous, Late Cretaceous, and Cenozoic to present). These movements formed deeply buried reservoirs with complex in situ stresses and rapid directional changes, influencing the state of shale gas reservoirs fractures. Numerical modeling applied to model the stress field in the three periods showed that the maximum compressive horizontal principal stress (sigma(Hmax)), strain rate, and fault slip rate regimes transformed from a thrust and strike-slip regime to a thrust and strike-slip regime to a thrust regime. The sigma(Hmax) direction changed from NW-SE and WNW-ESE to WNW-ESE and nearly E-W and then to multiple directions. The magnitude of strain rate changed from -16 similar to -15 to -17.7 similar to -15.6 to -18.8 similar to -15.8. The fault slip rate changed from 0 to 0.029 mm/a to 0-0.0026 mm/a to 0-0.0012 mm/a. These data strongly agree with data from drilled wells and outcrops and show that the present-day stress field is the superposed effect of multistage movements. Semiquantitative research was conducted on shale gas fracture openness and fracture development. Fracture openness is favorable when the angle between the sigma(Hmax) direction and nearby faults is <= 45 degrees and the distance from the fault is >2 km, and fracture development is favorable when the magnitude of the strain rate is <-17.6 and the fault slip rate is <0.00036 mm/a. Accordingly, we predicted fractured shale gas reservoirs.

On 17 November 2021, a moment magnitude (Mw) 5.0 earthquake occurred off the Yancheng city in the South Yellow Sea. This earthquake has caused ground motions and been felt by people in a few megacities in east China, for example, Shanghai, Nanjing. However, due to limited seismic data, the focal fault and mechanism of this earthquake remain unknown. Here, we combine the seismic profiles, seismicity, focal mechanism, well data with regional tectonics to investigate the seismotectonics of this event and the possible role of fluid migration in triggering the earthquake. Our new results suggest that two sets of preexisting strike-slip faults were developed near the epicenter of the Yancheng earthquake, including the north–northeast-trending fault F1, the North Wunansha fault, and the northwest-trending fault F5. These preexisting faults have been reactivated entirely or partly with dextral and sinistral motions during the Miocene to Quaternary. Fault F1 runs through the epicenter of the Yancheng earthquake and is therefore interpreted to be the seismogenic fault. Various igneous complexes and associated hydrothermal vent complexes have been identified in the vicinity of the reactivated fault F1 and other strike-slip faults. Combined with the published igneous rock ages from nearby region, the igneous and hydrothermal activities were suggested to be continue until the Miocene and Quaternary, which are coincident with the reactivation of the preexisting strike-slip faults. The reactivation of the preexisting fault, and igneous and associated hydrothermal activities were suggested to be caused by the subduction of Pacific and Philippine Sea plates and collision of India and Eurasia plate. The hydrothermal fluids may have migrated through the preexisting fault F1 and other strike-slip faults, which enhanced the reactivation of these faults and in turn promoted the fault slip, eventually triggering the Yancheng earthquake and other historical events in the study area.

ObjectiveThis study explores the accuracy of drilling core reorientations by using remanent magnetization.MethodsTo this end, paleomagnetic analyses were carried out on 43 Silurian sandstone samples collected from five boreholes (TKQ101, SHUN9, TAT19, TZ18, and TS108)in the Tarim Basin. Meanwhile, rock magnetic measurements, scanning electron microscope (SEM) and energy dispersive spectral (EDS) observations were conducted on representative samples to identify the predominant magnetic carriers. Furthermore, the paleocurrent direction inferred from the corrected maximum magnetic susceptibility (Kmax)axis of the anisotropy of magnetic susceptibility (AMS) using remanent magnetization was analyzed.ResultsAMS results indicate a sedimentary fabric preserved in the studied drilling cores, suggesting their stratigraphy are overall horizontal.Rock magnetic results, SEM and EDS observations reveal that magnetite is the dominant magnetic carrier for the TKQ101 samples, with small amounts of goethite and hematite, while pyrrhotite and magnetite are the dominant magnetic carriers for the other samples. The demagnetization results indicate that the viscous remanent magnetization (VRM) acquired in the present geomagnetic field and the characteristic remanent magnetization(ChRM) of the Silurian formation can be isolated for the TKQ101 samples, where the original azimuth rotations ( R, R') estimated by VRM and ChRM are consistent. Furthermore, the paleocurrent direction inferred from the corrected Kmax is supported by the geological evidence, suggesting a counterclockwise rotation of 258.0°-262.0°of the TKQ101 drilling cores. Only one remanence component was isolated for the majority (~90%) of samples from the other four boreholes, which is a superposition component of the VRM acquired in present geomagnetic field and the chemical remagnetization caused by fluid activities, such as oil-gas migration and accumulation, during the Himalayan period. Therefore, it is more reliable to reorient these drill cores by using the VRM component, with confirmation of the paleocurrent direction inferred by the corrected Kmax and geological evidence. ConclusionIn summary, to restore the original orientations of these drilling cores, the following rotation angles are required: 258.0°-262.0° counterclockwise rotation for the TKQ101 drill cores; 148.1°, 221.2°, and 318.2° counterclockwise rotation for the 4th, 5th and 6th sections from the borehole SHUN9, respectively; 269.8° and 155.9° counterclockwise rotation for the sections 3 and 5 from the borehole TAT19, respectively; 239.3° and 256.6° counterclockwise rotation for drill cores from the boreholes TS108 and TZ18, respectively.

Upper Ordovician Wufeng to Lower Silurian Longmaxi formations in Nanchuan region, as an important shale gas productive layer, is characterized by large shale thickness, deep burial depth, and complex in-situ stress with rapid direction changes. Therefore, the study of in-situ stress field is of significance for effective deve-lopment of shale gas in the study area. In order to clarify the characteristics and distribution of the in-situ stress field, the SHELLS finite element stress field modeling method, with faults, topography, heat flow, petrophysical parameters and boundary conditions as constraints, was used in the study of the stress field in the Wufeng-Longmaxi formations in the Nanchuan region.The results indicate that the maximum compressive horizontal principal stress is in thrust regime and that there are four principal stress directions and regions in general: NW-SE, NE-SW, near EW and near SN. The strain rate is in thrust regime, with three regions of low strain rate (magnitude ≤ -18), medium strain rate (magnitude between -18 and -17.6) and high strain rate (magnitude ≥ -17.6) and their corresponding NE-SW, NW-SE, SN and EW spreading directions. The fault slip rate regime is in thrust, the fault slip rates range from 0 to 0.001 2 mm/a. The modeled results of the maximum compressive horizontal principal stress, the strain rate and fault slip rate were compared with the measured data respectively, including the maximum compressive horizontal principal stress directions measured in drilled wells, the regime and magnitude of strain rate in Guizhou and Chongqing, and the properties of regional faults. The modeled results showed high agreement with the measured data, indicating the accuracy of the predicted results. Finally, based on fracture openness and fracture development revealed by modeled results, favorable fractured reservoir development zones for shale gas was evaluated, and class Ⅰ and Ⅱ zones for further exploration and development were predicted.

AbstractThe Nanchuan region is located on the southeastern margin of the Sichuan Basin, South China. Silurian Wufeng-Longmaxi Formation, buried between 2000-4500m deep in this area, is an important shale gas-producing formation. Influenced by multi-phase tectonic action during Mesozoic- Cenozoic [1], the maximum compressive horizontal principal stress (σHmax) directions are complex and the orientation changes rapidly (55°-135°). Therefore, effectively predicting the maximum compressive horizontal principal stress (σHmax) is important for improving the shale gas production capacity and optimizing the fracturing scheme development.In this paper, the SHELLS finite element stress field modeling [2] was introduced and used to understand the above problems. Based on the increased and improved resolution of its program, and faults topography, heat flow, petrophysical parameters, and boundary conditions in the shale gas target layer, the σHmax directions in the study area were modeled and calculated. The prediction results show that σHmax directions in the Nanchuan region vary multi-directionally (0-180°), and are consistent with 11 of the 13 drilled wells, with only two drilled wells having minor differences (Figure 1). 85% of the predicted wells are consistent with the measured wells, achieving significant geological results and laying the foundation for the effective development of shale gas production capacity and optimized fracturing schemes in the area.Keywords: Stress field modeling, maximum compressive horizontal principal stress directions, shale gas, mid-deep, the Nanchuan regionFigure 1 σHmax directions in the Nanchuan region compared to actual drillingReferences:[1] Tang J G., Wang K M., Qin D C., Zhang Y., Feng T., 2021. Tectonic deformation and its constraints to shale gas accumulation in the Nanchuan area, southeastern Sichuan. Bulletin of Geological Science and Technology. 40(5), 11-21. ( in Chinese version).[2] Bird, P., 1999. Thin-plate and thin-shell finite-element programs for forward dynamic modeling of plate deformation and faulting 1. Comput. Geosci. 25, 383–394.

Hydrocarbon exploration in the Neoproterozoic extensional basins in the Yangtze Craton of South China has made prominent progresses in the past decades. However, the spatial distribution of source rocks across the craton still remains unclear. Here, we use outcrop observations, borehole data, and reflective seismic profiles to investigate the prototype, distribution and sediment infilling of these basins in the Yangtze Craton during the periods of source rock deposition. The basin prototype is categorized based on its tectonic origin and structural-sedimentary feature as follows. (1) During the deposition of the Datangpo Formation, rift basins extensively developed, band are characterized by a series of graben or half graben structures that consist of basin-controlling normal faults. The source rocks in the Datangpo Formation were deposited as the inner shelf basin or deep shelf facies, obtaining high thickness (i.e., 200 m) in the Wuling rift basin. (2) During the deposition of the Doushantuo Formation, the intracratonic rift basin and passive continental margin basin formed. These basins were controlled by syn-depositional faults that inherited the existing rift fault structures. The source rocks of the Doushantuo Formation were deposited as shelf lagoon, slope to deep-water basin facies. (3) During the deposition of the Dengying Formation, the intraplatform rift basin and passive continental margin basin developed with influence of regional tectonic extension. Not only are these basins affected by the preexisting faults, but also by the newly developed syn-depositional faults. The argillaceous source rocks of the Dengying Formation deposited as slope and deep-water basin facies. Further in-depth analyses revealed that a range of mechanisms may have contributed to the formation and distribution of source rocks in the Yangtze Craton, such as the break-up of the Rodinia Supercontinent, paleaolatitudes, glacial-interglacial geological events, basin extension and sedimentary environments. By integrating the distribution of the source rocks and the late tectonic reworking, this study predicts several targets for the source rock distribution in the Yangtze Craton, including in the central Sichuan, northeastern Sichuan, southern Shanxi, western Hubei, northeastern Guizhou-western Hunan, and the northeastern Guangxi-central Hunan areas.

针对古生代中国中西部华北、华南和塔里木三大陆块在全球洋-陆格局中的古地理位置还存在的争议问题,本论文以国际最新的古地理位置重建研究方法和思路,在对中国三大陆块盆地(鄂尔多斯、四川和塔里木盆地)古生界钻井岩心的古地磁实测研究、全球古生代古地磁数据收集与有效性筛选处理、全球主要地质事件约束等多参数融合分析的基础上,采用最新的GPlates板块重建方法,对中国华北、华南和塔里木三大陆块在全球洋-陆格局中的古地理位置进行了重建和定位.研究结果表明:古生代三大陆块主要在全球士 30°之间的南北中低纬度之间迁移;三大陆块在古生代至少发生了 3次不同的顺时针旋转和方位角转换;三大陆块运移速率至少经历了 3次以上不同高、低速度间的转换与变化过程;响应于古生代全球洋-陆形成与演化,中国三大陆块古构造格局总体上经历了洋盆扩张下的"多岛洋"离散、俯冲碰撞下的离散-汇聚并存、俯冲消减下的差异汇聚隆升、新旧洋盆转换下的差异汇聚-离散、拼合与地幔柱控制下的差异汇聚-离散内部拉张的差异性演变过程.古生代中国三大陆块在全球洋-陆格局中的位置与差异性演变,奠定了中国三大陆块古生代不同性质盆地的形成与演化、不同层系油气烃源、储集原始物质差异性发育的基础.

Early Mesozoic geodynamic and tectonic relations between different blocks in East China remain controversial. The Subei-South Yellow Sea Basin (SB-SYSB) is located at the junction of different blocks and tectonic zones, including the North China Block (NCB), South China Block (SCB), Sulu Orogen and Tan-Lu Fault Zone (TLFZ). Therefore, the basin is a key location for understanding the regional geologic evolution of East China. Here, we present the geometry and kinematics of opposite thrust systems (OTSs) under the SB-SYSB based on seismic profiles, well data, magnetic reversion data and field observations. The OTSs are composed of two sets of thrust systems with opposite senses of motion: the northern top-to-the-southeast thrust system (N-TS) and southern top-to-the-northwest thrust system (S-TS). According to the structural styles, the N-TS and S-TS can be divided into the root, middle and frontal belts. The strikes of thrusts show a shift from NNE to NE- ENE and then to nearly E-W from west to east. The OTSs were suggested to have formed during the end of the middle Triassic to the middle Jurassic, and its deformation intensity decreased from west to east and from the root belt to the frontal belt. Combining these lines of evidence with published geochronological data for the Dabie-Sulu Orogen and other structural elements in East China, we provide a comprehensive synthesis and propose a new tectonic model to explain the early Mesozoic geodynamic and tectonic relations in East China. We emphasize the following points: (1) The Sulu Orogen might extend to the Northern Depression in the offshore SYSB and be bounded by the North Fault of the Central Massif to the south, indicating that the Sulu Orogen is significantly wider than stated in previous studies. (2) The N-TS was driven by the subduction of the YZB and the exhumation of the Sulu HP–UHP metamorphic rocks. In contrast, the S-TS was probably controlled by the orogenic uplift of the Jiangnan Orogen. (3) The dragging of the thrusts in the SB-SYSB and adjacent areas indicates that the sinistral motion of the TLFZ was coeval with the formation of the OTSs and was likely caused by the clockwise rotation of the SCB. (4) Finally, this clockwise rotation probably triggered intense corner compression between the Sulu Orogen, TLFZ and East Marginal Fault of the Yellow Sea, resulting in a genetic relation among the Sulu Orogen, the SCB, the Korean Peninsula and the Xu-Huai Belt.

Coeval Neoproterozoic mafic dykes with a well‐constrained isotopic age of 925 Ma are distributed in the North China Craton (NCC) of China and São Francisco Craton (SFC) of Brazil. Several recent studies favor the hypothesis that these two cratons were connected during 925 Ma and constituted building cratons for the supercontinent Rodinia. However, the paleo‐positions of the two cratons in Rodinia have not yet been paleomagnetically resolved. This paper presents the paleomagnetic results of these dykes in both NCC and SFC. Detailed thermal and alternating‐field demagnetization revealed that these dykes record stable components of magnetization with unblocking temperatures below the Curie temperature of magnetite. Rock magnetic results and scanning electron microscope analysis further confirm that the major magnetic minerals in dyke samples are pseudo‐single domain titanomagnetites. The mean directions of the characteristic remanent magnetization (ChRM) of the dykes are distinct from those of rocks of different ages in the sampling localities, and are supported by positive baked contact tests, indicating primary remanent magnetization. The ChRM of the SFC dykes also exhibits dual polarity. Our results suggest that the NCC and SFC were in the moderate to high paleolatitudes of the Southern Hemisphere during approximately 925 Ma, suggesting a possible paleogeographic connection between the two cratons. A new paleogeographic reconstruction of both cratons during 925 Ma is proposed, which is supported by other geological evidence.

The NE-trending Liaodong Bay Subbasin (LDBS), a subunit of the Bohai Bay Basin (BBB), developed along the Tan-Lu Fault Zone (TLFZ) in eastern China. The LDBS is controlled by both extensional and dextral strike-slip fault systems and has an episodic evolutionary history, leading to a poor understanding of its tectonic origin. In this paper, through interpretations of seismic data and other geological and geophysical data, four best-fit finite element models were generated to reveal the tectonic development of the LDBS and the whole BBB. The deformation features predicted by the modelling results are consistent with the geological evidence. The modelling results revealed that the extension directions of the LDBS changed from WNW-ESE during the Paleocene-early Eocene, to NW-SE during the middle-late Eocene and then to NWN-SES or nearly N-S in the Oligocene and Miocene. The changes in the extension direction resulted in a strike-slip transition of the TLFZ in approximately the middle-late Eocene, from normal to dextral transtensional, and transformed the LDBS and the whole BBB from an extensional basin into a dextral transtensional basin. This transformation was likely triggered by the kinematic adjustment of the Pacific Plate from NNW to WNW in the middle-late Eocene, but was maintained and enhanced by the Indian-Asian collision during the rest of the Cenozoic.

The Northern Depression of the South Yellow Sea Basin underwent two episodes of tectonic inversion from the latest Eocene to Oligocene and in the Pliocene, respectively. During the inversion, the structural depression controlled previously by extensional faults was subjected to compression and erosion. Structural interpretation on 2D marine seismic data suggests that the structural styles associated with inversion are predominantly reactivated NNW-trending faults, fault-related folds, newly-formed reverse faults and unconformities. Here we used structural restoration technique to illustrate the sequential development of these inversion structures and to estimate the amount of deformation. To explore the mechanism of the basin inversion, the finite element modeling was employed to reproduce the inversion deformation in the Northern Depression. The deformation features predicted by modeling are well consistent with our structural observations. Based on a combination of these results and regional tectonic history, we propose that the inversion deformation in the South Yellow Sea Basin was predominantly driven by the enhanced dextral strike-slip motion along the Tan-Lu Fault. The interactions between the Eurasian plate and the Pacific realm resulted in the varying dextral movement along the Tan-Lu Fault, and the Cenozoic tectonic inversion in the South Yellow Sea Basin was a tectonic response to these processes.

The development of the sedimentary basin in the South Yellow Sea that lies between the Chinese mainland and the Korean Peninsula well documents the tectonic evolution of eastern China. However, the Moho morphology and its relationship with the basin in this area remain poorly understood. Here we used high‐resolution 2D seismic lines and well data to map the geometry, structure, and distribution of the sedimentary basin in the South Yellow Sea. Our results suggest that the South Yellow Sea Basin can be divided into two distinct depressions and three uplifts. The depressions consist of eight depositional sags that are largely controlled by ENE‐, EW‐, and WNW‐striking normal faults. The basin depth reaches 9,500 m in the depressions, but is only <2000 m in the uplift zones. Calculated using a gravity stripping method, the Moho depth varies between 27.4 and 31.5 km. The basin is isostatically compensated and the Moho morphology approximately mirrors that of the basin basement. The Moho lows correspond to the uplift zones and Moho highs correspond to the depression zones, with exception of a sag in the Northern Depression. This exception is caused by the presence of a geological body of high velocity and high density beneath the sag. This body is likely to represent high‐pressure metamorphic rock that initially formed during the collision between the Sino‐Korean and Yangtze cratons and are currently overlain by the sedimentary basin. Based on the stretching factors and strain rates of the South Yellow Sea Basin, we propose that development of the basin was primarily driven by the subduction and retreat of the Pacific Plate since the Late Cretaceous, combined by far‐field effects from the convergence between the Indian and Eurasian plates during the Cenozoic.

Based on a comprehensive review of published results, the plate tectonic setting of the Neoproterozoic basins in the Yangtze Craton can be summarized as evolving from the Qingbaikou convergent continental margin to the Nanhua-Sinian divergent continental margin. Four phases of basin evolution are identified in the Neoproterozoic Yangtze Craton based on the prototype basin classification scheme: a) the early Qingbaikou period (ca. 1000-820 Ma), with back-arc spreading basins on the western and northern Yangtze margins and the interior, and a retro-arc foreland basin on the southeastern Yangtze margin; b) the late Qingbaikou period (ca. 820-720 Ma), with back-arc spreading basins on the western and northern Yangtze margins and extensional down-faulted basins on the southeastern Yangtze margin and the interior of the carton; c) the Nanhua period (ca. 720-635 Ma), with rift basins on the southeastern, western, and northern Yangtze margins and the interior; and d) the Sinian period (ca. 635-541 Ma), with intracratonic rift basins in the interior of Yangtze Craton and divergent marginal subsidence basins on the southeastern and northern Yangtze margins. The temporal sequence and spatial distribution of the major prototype basins associated with the four stages of basin evolution in the Yangtze Craton were further identified. By comparing the petroleum exploration practices in China and abroad, this paper concludes that the Nanhua rift basins on the southeastern and northern Yangtze margins, the Sinian divergent marginal subsidence basins on the southeastern and northern Yangtze margins and the intracratonic rift basins in the interior Yangtze Craton were most conducive to source rock formation and are target regions for future oil and gas exploration.

近年来,随着扬子克拉通埃迪卡拉系陡山沱组页岩气勘探获得重大突破,深入和细化陡山沱期构造-岩相古地理就显得迫在眉睫.基于大量野外露头和最新钻井资料,结合前人研究成果,作者对陡山沱期构造-岩相古地理进行了分析、研究和图件编制.研究认为:扬子克拉通埃迪卡拉纪陡山沱期,受控处于罗迪尼亚超大陆西北边缘的古地理位置和超大陆大规模裂解之后的热沉降作用初期的成盆构造环境,其古地理特征总体呈现出西高东低、北高南低,四古陆剥蚀区(汉南、康滇、牛首山和江南古陆)、三台地区(上扬子、中下扬子和浙北台地)与四盆地区(扬子东南缘与北缘坳陷、万源—达州和湘鄂西内裂陷)相间的沉积面貌和格局.其中,台地区以局限—开阔台地,盆地区以台缘斜坡、陆棚和半深海等为主要优势相.4个古陆是扬子陡山沱组主要的碎屑物源区,下伏裂谷盆地构造和陡山沱期发育的同沉积断裂,共同控制了埃迪卡拉系陡山沱组构造-沉积特征.提出陕南、川东北、鄂西和湘黔渝临区是最有利的陡山沱组烃源岩分布区,其次是浙北—皖南地区.有利烃源岩分布区及其邻区是扬子深层—超深层常规天然气或页岩气勘探值得高度关注的区域.