Marine and Petroleum Geology最新文献

{"title":"Pyrite morphologies in Bazhenov Formation source rocks: diversity, systematic classification, sulfur isotopic composition and insights into sedimentation and diagenesis processes","authors":"Alina Karamova,&nbsp;Tagir Karamov,&nbsp;Mikhail Spasennykh","doi":"10.1016/j.marpetgeo.2025.107535","DOIUrl":"10.1016/j.marpetgeo.2025.107535","url":null,"abstract":"<div><div>Pyrite is a common authigenic mineral in organic-rich source rocks, which is diverse in morphology and carries valuable genetic information about geological processes. This study proposes comprehensive genetic morphological classification of pyrite aggregates in organic-rich shales of the Bazhenov Formation – one of the world largest source rock located in the Western Siberia. Scanning electron microscopy was used to analyze over 530 samples from 17 wells, identifying various types of pyrite such as framboids (with corresponding subtypes based on orderliness of the internal structure, crystallographic shape of microcrystals, infilling of internal structure, and integrity), euhedral crystals, and pyrite pseudomorphosis. The obtained sulfur isotopic composition for framboidal pyrite, which turned out to be the lightest (δ³⁴S vary in the range from −55.38 ‰ to −26.02 ‰), is indicative of anoxic conditions on seafloor. Euhedral pyrite develops in diagenesis under limited sulfate supply, reflecting slow growth in pore-water depleted in ³²S (δ³⁴S values range from +15.05 ‰ to +26.49 ‰). Described morphological types cover the diversity of pyrite forms in other similar geological objects around the world, which allows pyrite to be used as a geochemical proxy for paleoenvironmental reconstructions and hydrocarbon exploration, enhancing understanding of sulfur cycle and basin evolution.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"182 ","pages":"Article 107535"},"PeriodicalIF":3.7,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144588495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Developmental model and filling response characteristics of paleokarst conduits in the Middle-Lower Ordovician strata of Well 094 area, Tahe Oilfield","authors":"Jiyuan Gao ,&nbsp;Nuoyu Wang ,&nbsp;Heng Zhang ,&nbsp;Zhongxian Cai","doi":"10.1016/j.marpetgeo.2025.107596","DOIUrl":"10.1016/j.marpetgeo.2025.107596","url":null,"abstract":"<div><div>The Ordovician strata in the Tahe Oilfield of the Akekule Low Uplift, Tarim Basin, host diverse palaeokarst fracture–cavity reservoirs. Among these reservoirs, the large-scale epignic karst conduit system that formed during the early Hercynian represents one of the most significant reservoir spaces. The Well 094 well block, located in the Carboniferous-covered western slope area of the Tahe Oilfield, contains typical Ordovician palaeokarst conduit-type reservoirs. On the basis of 3D seismic and well logging data, in this study, the palaeokarst hydrogeomorphic conditions of the Ordovician strata in this area are reconstructed; the spatial distribution, developmental conditions, and filling characteristics of large-scale branchwork karst conduits are analysed; and their controlling factors are investigated. The results indicate that the Ordovician strata in the Well 094 well block were situated in the early Hercynian karstification zone, characterized by a typical binary flow field structure of a karst watershed. The karst landform exhibits medium-to-high relief, with well-developed asymmetrical branchwork surface drainage systems converging from north to south into a karst canyon. The karst conduits are predominantly developed approximately 120 ms below the top of the Lower-Middle Ordovician series. The development of these conduits was jointly controlled by the steep topographic gradient of the Ordovician strata, the syncline-confined groundwater convergence zone between secondary anticlines, and the water-conducting effects of NNE- and NNW-trending strike-slip faults. The karst conduits display distinct east‒west differential evolution. The eastern conduits experienced intense vertical erosion and roof collapse, forming a subsurface fluvial window geomorphology with severe clastic infilling, whereas the western conduits maintained relatively stable configurations. This finding suggests that conduit evolution is influenced by tectonic uplift and the hydraulic gradient, with the degree of infilling closely related to the watershed area, fault activity, and evolutionary stage. Highly evolved conduit segments tend to exhibit more severe infilling.The complete filling of the cave not only reduces porosity but also significantly compromises the reservoir's effective storage capacity. These findings provide a theoretical basis for evaluating the effectiveness of similar karst fracture–cavity reservoirs worldwide.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"182 ","pages":"Article 107596"},"PeriodicalIF":3.6,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145044509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Temporal and spatial variations of redox conditions in the middle Triassic Chang 7 member of the Yanchang formation, Ordos Basin, North China","authors":"Hanlin Liu ,&nbsp;Yuangeng Huang ,&nbsp;Xiangdong Zhao ,&nbsp;Wei Wang ,&nbsp;Xincheng Qiu ,&nbsp;Zhen Qiu ,&nbsp;Juan Han ,&nbsp;Zhen Shen ,&nbsp;Yujie Li ,&nbsp;Ganlin Hua ,&nbsp;Zhong-Qiang Chen ,&nbsp;Caineng Zou","doi":"10.1016/j.marpetgeo.2025.107565","DOIUrl":"10.1016/j.marpetgeo.2025.107565","url":null,"abstract":"<div><div>The Chang 7 member of the lower Yanchang Formation, situated within the Ordos Basin, dates back to the Ladinian stage of the late Middle Triassic. These strata, notable for their organic-rich black shales, serve as a key lacustrine hydrocarbon-bearing unit in China. The Chang 7 shales encompass a wide array of vertebrate, invertebrate, and plant fossils, offering valuable perspectives on the ecological recovery of lacustrine systems following the end-Permian mass extinction (EPME). Redox conditions within the water column play a critical role in influencing organic matter deposition and shaping lacustrine biodiversity. Nonetheless, prior investigations into redox dynamics during the formation of the Chang 7 shales have predominantly relied on single redox proxies or isolated sampling locations, which restrict a comprehensive understanding of the redox evolution across the entire Ordos Basin. For these reasons, this study employs framboidal pyrite size statistics, pyrite sulfur isotopes, major and trace element concentrations, and lipid biomarkers of five Ladinian-age wells from both deep and shallow sedimentary facies to rebuilt up evolutional patterns of redox conditions in the Basin. Our results reveal remarkable difference of redox conditions amongst deposition periods of three submembers. Notably during the formation of the Chang 7₃ submember (lower Chang 7 member), the Ordos paleo-lake exhibited progressively declining oxygen levels, transitioning from dysoxic to anoxic conditions in deeper facies. Dysoxic conditions prevailed in the deep facies, with transient anoxic conditions emerged. By contrast, evidence indicates that the Chang 7₂ submember (middle Chang 7 member) was primarily deposited under fluctuating dysoxic-oxic conditions, while the Chang 7₁ submember (upper Chang 7 member) was formed in predominantly oxic environments. Collectively, the Chang 7 member shows remarkable organic matter preservation, with an average total organic carbon (TOC) content of 11.02 wt%, and peak TOC levels reaching 35.8 wt% in the Chang 7₃ submember. These findings indicate that by the Ladinian, the Ordos paleo-lake had already achieved a high level of productivity, capable of sustaining a fully developed, trophically complex lacustrine ecosystem in the aftermath of the EPME. The relatively oxygen-depleted bottom waters during deposition of the Chang 7₃ submember provided favorable conditions for the preservation of the abundant and diverse biota. This comprehensive analysis offers valuable insights into the lacustrine paleoenvironmental conditions and biotic recovery following the EPME, and provides important clues for the formation environment of source rocks.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"182 ","pages":"Article 107565"},"PeriodicalIF":3.6,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144721568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cenomanian channel system evolution of Mundaú Sub-basin deepwater, Brazilian Equatorial Margin: Reservoir characterization using machine learning techniques","authors":"Ian de Oliveira Souza Cerdeira ,&nbsp;Karen Maria Leopoldino Oliveira ,&nbsp;Jorge de Jesus Picanço Figueiredo ,&nbsp;Heather Bedle ,&nbsp;Narelle Maia de Almeida ,&nbsp;Ana Clara Braga Souza","doi":"10.1016/j.marpetgeo.2025.107540","DOIUrl":"10.1016/j.marpetgeo.2025.107540","url":null,"abstract":"<div><div>Submarine channel systems have garnered significant attention in recent years due to their importance in petroleum exploration and favorable reservoir characteristics. Specifically, the Brazilian Equatorial Margin basins have attracted considerable interest from various sectors because of substantial hydrocarbon discoveries in adjacent basins. In the Mundaú Sub-basin (Ceará Basin, NE Brazil), recent studies have identified a series of sand-rich structures associated with a Cenomanian submarine channel system. However, despite these advancements, the depositional elements, sedimentary architecture, and stratigraphic sequences remain poorly understood. This paper aims to integrate robust quantitative geophysical techniques, including unsupervised machine learning methods, multi-attribute analysis, and RGB blending, to clarify the main evolutionary stages of the Cenomanian submarine channel-lobo system in the central portion of the aforementioned Sub-basin and their controlling factors. We utilized data from four exploration wells drilled in the deep waters of the Mundaú Sub-basin, along with a 2200 km² seismic volume covering the study area. Our integrated approach identified three main evolutionary stages. The first stage is characterized by straight to low-sinuosity confined channels on the upper to middle slope, alongside poorly confined channels and splays on the lower slope to basin floor, primarily comprising sand-prone layers developed during a Falling Stage System Tract. The second stage exhibits low to moderate sinuosity confined channels in the upper to middle slope, with significantly poorly confined channels and splays on the lower slope to basin floor, also dominated by sand-prone layers developed in a Lowstand Tract System. The final stage features a high-sinuosity confined channel with dominant sand-prone and sand/mud-prone layers developed in a Transgressive System Tract. all stages and across almost the whole region, sand-prone and sand/mud-prone facies were identified and associated with various depositional elements at different scales. the presence of sand-prone layers in all stages is thought to result from high-density turbidity currents driven by a narrow shelf and stepped slope. The mapped features and predicted facies indicate an unexplored area with sand-rich layers likely possessing good lateral and vertical connectivity. Important structures that may facilitate oil migration were identified, highlighting the high exploration potential of the Cenomanian submarine channel system in the Mundaú Sub-basin.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"182 ","pages":"Article 107540"},"PeriodicalIF":3.7,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144604136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating key pressure loss factors in the Wufeng-Longmaxi formation shale gas reservoirs, Southern Sichuan: A quantitative approach","authors":"Nengwu Zhou ,&nbsp;Guangshun Xiao ,&nbsp;Shuangfang Lu ,&nbsp;Bo Song ,&nbsp;Jun Wang ,&nbsp;Zhong Chu ,&nbsp;Xinyu Jiang ,&nbsp;Yang Liu ,&nbsp;Wenbiao Li ,&nbsp;Pengfei Zhang ,&nbsp;Guohui Chen ,&nbsp;Min Wang","doi":"10.1016/j.marpetgeo.2025.107560","DOIUrl":"10.1016/j.marpetgeo.2025.107560","url":null,"abstract":"<div><div>Pressure loss in the Wufeng-Longmaxi Formation shale gas reservoirs of the southern Sichuan Basin is a complex issue. This occurrence is influenced by several critical factors: faults, stratigraphic properties, fold structures, and the timing and magnitude of uplift events. While we know these factors are significant, their quantitative impact and individual contributions to pressure loss remain poorly understood. In this study, we integrate the burial and thermal history of the basin to reconstruct the evolution of key reservoir parameters, including formation temperature, hydrostatic pressure, overburden pressure, total porosity, water-filled porosity, and gas adsorption porosity. Using this framework, we simulate the effects of different preservation conditions on pressure loss within shale gas reservoirs and evaluate the relative contributions of these controlling factors. Simulation results revealed that the location of fault development, particularly its penetration through the caprock, is the predominant factor governing pressure loss in local shale gas reservoirs. In contrast, the scale of fault development has a relatively minor impact. Additionally, the thickness and vertical diffusion coefficient of the caprock, along with the time, emerged as secondary controlling factors that substantially influence the rate of pressure loss across the shale gas reservoirs. Furthermore, the dip angle of synclinal folds and the lateral diffusion coefficient act as accelerators of pressure loss, potentially leading to rapid depletion of reservoir pressure. Conversely, the properties of anticlines exhibit minimal influence on pressure loss. These findings provide valuable insights for the management and optimization of shale gas reservoirs in the Wufeng-Longmaxi Formation.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"182 ","pages":"Article 107560"},"PeriodicalIF":3.7,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144670281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the limitations of spot permeability measurements to quantify bulk permeability of bioturbated reservoirs: Insights from digital rock physics modeling","authors":"Ahmed Refaat ,&nbsp;Hassan A. Eltom ,&nbsp;Ammar El-Husseiny","doi":"10.1016/j.marpetgeo.2025.107577","DOIUrl":"10.1016/j.marpetgeo.2025.107577","url":null,"abstract":"<div><div>Substantial permeability contrasts between the fine-grained host rock matrix (HRM) and the coarse-grained burrow fillings (BF) are observed in bioturbated reservoirs, which are characterized by burrows that create a dual-porosity system. Consequently, assessing bulk permeability becomes particularly challenging, as these reservoirs often exhibit permeability contrast between HRM and BF spanning several orders of magnitude. To address this issue, the present study utilizes insights from digital rock physics modeling to critically examine the limitations of spot permeability measurements in accurately estimating bulk permeability in bioturbated systems. Specifically, we applied an integrated workflow to examine samples from a bioturbated interval in the upper Hanifa Formation in Saudi Arabia, incorporating spot permeability measurements, petrographic analysis, micro-CT scanning, pore network modeling, and permeability simulations to evaluate the effectiveness of spot permeability data in capturing bulk flow behavior. Our findings revealed that although spot permeability data are valuable for identifying localized permeability trends, they can be misleading when used to infer true bulk permeability, as they may fail to account for isolated or poorly connected pore systems. In particular, our results showed a significant discrepancy emerged between the CT scan data and spot measurements: while the CT imaging showed isolated and poorly connected pores within the burrow fillings—resulting in negligible flow during simulations—the spot measurements indicated substantially higher permeability values, ranging from 2.65 mD to 796.30 mD. This contrast underscores the complexity of relying on localized measurements to characterize bulk reservoir properties. Therefore, achieving more accurate permeability estimations in bioturbated reservoirs necessitates a comprehensive approach that integrates spot permeability data with high-resolution imaging and digital simulation techniques.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"182 ","pages":"Article 107577"},"PeriodicalIF":3.6,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144858215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Oil cracking with different water contents: New insights into the influence of water on the phase evolution and thermal stability of deep crude oil","authors":"Aizimaiti Maimaiti ,&nbsp;Qi Wang ,&nbsp;Fang Hao ,&nbsp;Jinqiang Tian ,&nbsp;Xianzhang Yang ,&nbsp;Haizu Zhang ,&nbsp;Subi Abudouaini ,&nbsp;Fuyun Cong","doi":"10.1016/j.marpetgeo.2025.107602","DOIUrl":"10.1016/j.marpetgeo.2025.107602","url":null,"abstract":"<div><div>Water is widely distributed under geological conditions and has an significant influence on the process of oil cracking into gas. However, the mechanism of reservoir water content on the thermal stability and phase evolution of deep oil and gas reservoirs still needs further study. In this study, gold-tube pyrolysis experiments were conducted using oil, oil–water (3:2), and oil–water (1:4) mixtures, at constant heating rates of 2 °C/h and 20 °C/h. The experimental results show that water has little effect on the yield of C_1-5 hydrocarbons, but increases the yields of the non-hydrocarbon gases H₂ and CO₂. The hydrogen isotopic composition of methane, ethane, and propane generated during pyrolysis experiments with added water became increasingly enriched in deuterium with increasing water content and maturity. Our results demonstrate that disproportionation and hydrogen isotope exchange between water and crude oil significantly affect both the evolution of product yields and the hydrogen isotopic signatures of generated hydrocarbons. Extrapolation of kinetic parameters at a constant heating rate of 2 °C/Ma based on the thermal history of the Tabei area in the Tarim Basin indicates that water reduces the thermal stability of crude oil, which ultimately leads to a decrease in the depth threshold for liquid hydrocarbon preservation by about 1000 m. The PVT phase simulation results show that the effect of water on the cracking behavior of crude oil is strongest at the stage of EasyRo = 1.33 %–2.19 %. At EasyRo = 1.47 %, the presence of water leads to a decrease in the cricondentherm of the crude oil by about 33.8 °C and an increase in the cricondenbar by about 2.46 MPa.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"182 ","pages":"Article 107602"},"PeriodicalIF":3.6,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145060253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Origin of hydrogen sulfide in produced gas of Upper Permian shales from western Hubei, southern China: A preliminary study","authors":"Yasheng Cui ,&nbsp;Le Li ,&nbsp;Huan Yang ,&nbsp;Keliang Pan ,&nbsp;Jie Xin ,&nbsp;Yuanqing Hu ,&nbsp;Xiaogui Peng ,&nbsp;Feng Yang","doi":"10.1016/j.marpetgeo.2025.107570","DOIUrl":"10.1016/j.marpetgeo.2025.107570","url":null,"abstract":"<div><div>An unexpected moderate concentration (0.3 %–2 %) of hydrogen sulfide (H₂S) was detected in the produced gas from upper Permian shales in western Hubei, southern China. This raised the hypothesis that H₂S could either be a primary component of the shale gas reservoir or a secondary product generated by fracturing. This study systematically acquired data on desorbed gas composition, produced gas composition, sulfur isotopes of H₂S in the produced gas, ion chemistry of flowback water, and compiled fracturing and production data, to preliminarily investigate the origin of H₂S in the produced gas. The unusually low sulfur isotope composition of H₂S in the produced gas (3.20 ‰–4.48 ‰, with an average of 3.66 ‰) rules out contamination from overlying (Changxing Formation) or underlying (Huanglong Formation) gas-bearing layers via natural fractures or fracturing-induced pathways. A two-order magnitude difference in H₂S content between desorbed and produced gas indicates that most of the H₂S in the produced gas is not supplied by the primary gas reservoir. The estimated volume of produced H₂S (62,025 m³) greatly exceeds the theoretical maximum H₂S yielded from acid-rock reactions (4243.5 m³), ruling out this reaction as the major source of H₂S. The reservoir temperature (average 89.39 °C), coupled with a positive correlation between H₂S content and sulfate and calcium ions, suggests that fracturing-induced bacterial sulfate reduction (BSR) is the main driver for secondary H₂S formation. Thermochemical sulfate reduction (TSR) is unlikely due to temperature constraints.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"182 ","pages":"Article 107570"},"PeriodicalIF":3.6,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144781623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mud volcanism and diapirism along the Japan Trench axis: evidence for a complex earthquake plumbing system on the down-going plate","authors":"Myra Keep ,&nbsp;Troy Rasbury ,&nbsp;Cecilia McHugh ,&nbsp;Michael Strasser ,&nbsp;Ken Ikehara ,&nbsp;Charlotte Pizer ,&nbsp;Yasuyuki Nakamura","doi":"10.1016/j.marpetgeo.2025.107597","DOIUrl":"10.1016/j.marpetgeo.2025.107597","url":null,"abstract":"<div><div>Mud volcanoes occur in a variety of geodynamic settings, and are common in subduction zones, usually within the accretionary prism. Although mud volcanism occurs along the Ryukyu Trench in southern Japan, no such activity has been documented along the Japan Trench. Sub-bottom profile data from International Ocean Discovery Program Expedition 386 show acoustically anomalous features in the basin-fill stratigraphy consistent with mud diapirism and mud volcanism along the Japan Trench. Unusually these features occur in basins along the trench axis itself, and not primarily as part of the accretionary complex. We present evidence for diapirism along ∼600 km of the Japan Trench and for mud volcanoes in the central and northern part of the trench. Mud diapirism and nearby igneous volcanic activity shows close spatial relationships to flexural faults on the down-going plate, which may provide the plumbing system for mobile muds to reach the surface.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"182 ","pages":"Article 107597"},"PeriodicalIF":3.6,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145026784","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The sedimentary provenance of Upper Miocene Dongfang submarine fan, Yinggehai Basin: source-to-sink system unravelled through new detrital zircon U-Pb ages and heavy mineral analysis","authors":"Xingzong Yao ,&nbsp;Congjun Feng ,&nbsp;Wei Zhou ,&nbsp;Pengfei Wu ,&nbsp;Hongjun Qu ,&nbsp;Jiahao Lei ,&nbsp;Zhiqiang Chen ,&nbsp;Yanlong Ge ,&nbsp;Mengsi Sun","doi":"10.1016/j.marpetgeo.2025.107557","DOIUrl":"10.1016/j.marpetgeo.2025.107557","url":null,"abstract":"<div><div>The Upper Miocene Dongfang submarine fan, developed in the Yinggehai Basin, is considered one of the most valuable reservoirs in the northern South China Sea. However, the provenance of the fan remains a controversy between the Red River drainage area and Central Vietnam, hindering hydrocarbon exploration in the basin. In this study, heavy mineral analysis and detrital zircon geochronology of samples from the Upper Miocene intervals in four boreholes were conducted for provenance analysis of the fan. The occurrence of Cr-spinel and high leucoxene contents (34.3 %–85.9 %) in heavy mineral assemblages from these wells suggest sediment contributions from the Red River drainage area and Central Vietnam. Detrital zircon grains from the fan exhibit a wide U-Pb age range, including Luliangian, Jinningian, Caledonian, Indosinian, Yanshanian, and Himalayan populations. Multidimensional scaling (MDS) robustly supports a dual-provenance model consisting of the Red River drainage area and Central Vietnam. Furthermore, we propose that the Red, Ma, Lam, Gianh, and Ben Hai rivers served as sediment pathways owing to the similarities in zircon age distributions between the fan and modern drainage systems. Unmixing models employing the Kolmogorov-Smirnov (K-S) test D statistic quantify the relative source contributions, indicating a potential internal evolution of the fan. Among these, the Red River drainage area dominated the samples D132h and D1310h, accounting for 94.3 % and 86 % of detritus, respectively. Central Vietnam predominantly contributed 99.5 % of sediments to the sample D134h. For the sample D136h, 45.7 % of sediments were derived from the Red River drainage area and 54.3 % from Central Vietnam. The reconstruction of the source-to-sink system reveals that the global forcings (the uplift of the Tibetan Plateau, the expansion of Antarctic ice sheets) and regional adjustments (the intensification of East Asian monsoon, the reversal of Red River Shear Zone) collectively controlled the formation and development of Dongfang submarine fan. Specifically, the activity on the Red River Shear Zone destabilized the deltaic sediments along the western margin of Yinggehai Basin, generating sediment gravity flows that accumulated in the depocenter and formed the Dongfang submarine fan. The source-to-sink system model may provide valuable insights into the prediction of Upper Miocene reservoirs and guides the future hydrocarbon exploration in the basin.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"182 ","pages":"Article 107557"},"PeriodicalIF":3.7,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144633923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}