Marine and Petroleum Geology最新文献

{"title":"Quantitative prediction of fracture distribution in deep conglomerate reservoirs of the Bozhong 19-6 South structure, offshore Bohai Bay Basin, East China: Insights from numerical simulation of multiphase strike-slip regimes","authors":"Liang Zhou ,&nbsp;Chao Deng ,&nbsp;Li-ya Da ,&nbsp;Yu Xia ,&nbsp;He-wei Hu ,&nbsp;Kai Ji ,&nbsp;Chang-yu Fan ,&nbsp;Yong Cheng ,&nbsp;Yu-jie Ning ,&nbsp;Xiao-fang Yang","doi":"10.1016/j.marpetgeo.2025.107644","DOIUrl":"10.1016/j.marpetgeo.2025.107644","url":null,"abstract":"<div><div>Fracture development and distribution within the BZ19-6 South (BZ19-6S) conglomerate reservoirs is dominantly controlled by Cenozoic multiphase strike-slip stress regimes, critically influencing hydrocarbon migration, accumulation, and sweet-spot distribution. This study characterizes these complex fracture systems by first reconstructing strike-slip superimposed activity during three key tectonic periods (middle Eocene, Oligocene, present-day) using balanced cross-sections, throw-depth plots, and growth indices integrated with regional dynamics. A 3D geological model was then constructed from seismic data, sedimentary microfacies, and paleo-tectonic restorations. Concurrently, a heterogeneous geomechanical model was developed using well logs and rock mechanics tests. Finite element simulations, constrained by loading stress magnitudes from acoustic emission experiments (as boundary conditions), reconstructed paleo- and present-day tectonic stress fields for each period. By considering the principles of fracture mechanics with wellbore fracture statistics, models for tensile/shear failure rates and linear fracture density were established to quantify fracture evolution. Validation against exploration-well data confirmed prediction accuracy, thereby guiding new well placement in high-fracture zones. Key findings: (1) Distinct strike-slip superimposed patterns across periods generated superimposed structural styles with variable geometries and intensities; (2) The Middle Eocene-Oligocene fractures were primarily controlled by burial depth, whereas present-day fractures are jointly co-governed by burial depth and strike-slip faults. This study advances deep reservoir fracture prediction through high-resolution tectonic staging and stress superposition analysis, providing a quantitative framework for fracture evaluation and reservoir development.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"183 ","pages":"Article 107644"},"PeriodicalIF":3.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145418207","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 role of reservoir compartmentalization in the failure of reservoirs of structurally complex accommodation zones: an example from The Morgan Accommodation Zone, Gulf of Suez, Egypt","authors":"Zakaria Hassan ,&nbsp;Mohamed S. Hammed ,&nbsp;Ahmed E. Radwan ,&nbsp;Selim S. Selim ,&nbsp;Shaimaa Abdelhaleem","doi":"10.1016/j.marpetgeo.2025.107610","DOIUrl":"10.1016/j.marpetgeo.2025.107610","url":null,"abstract":"<div><div>Compartmentalization of hydrocarbon reservoirs represents a global challenge in assessing and developing proven fields due to the necessity for a detailed survey of the field structures, burial history, and pressure system. The geological complexity arising from overlapping fault segments, kinematically linked fracture networks, and heterogeneous stratigraphic juxtapositions within accommodation zones between Gulf of Suez rift segments results in highly variable reservoir performance—yielding prolific hydrocarbon production in some fields, while others remain non-productive—and contribute to the occurrence of multiple oil-water contacts within individual producing reservoirs. We use structural restoration, basin modelling, pore pressure and fracture gradient modelling to assess the pre-rift reservoir failure and the variation of the oil-water contact in the syn-rift reservoirs of the Morgan accommodation Zone, Gulf of Suez. Our results show that: (1) pre-Miocene source rocks are too shallow for maturation due to complex fault linkages and interaction; (2) immature pre-Miocene source rocks prevent effective hydrocarbon generation and charge; (3) no overpressure above the Eocene Thebes Formation; lack of charge attributed to either immature source rocks at juxtaposition points or sealing faults; (4) a fill-to-spill mechanism governs Miocene syn-rift oil-water contact variations; deeper oil-water contact in western blocks results from better connectivity to mature source kitchens west of GS327. These results offer crucial new insights into the interplay of pressure regimes, migration routes, and reservoir compartmentalization governing hydrocarbon plays in complex accommodation zones.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"183 ","pages":"Article 107610"},"PeriodicalIF":3.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145270561","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":"Lower Paleozoic salt diapirs in the northern part of the West Siberian Basin and the Enisey-Khatanga Trough: structural setting and petroleum habitat","authors":"Konstantin Sobornov","doi":"10.1016/j.marpetgeo.2025.107638","DOIUrl":"10.1016/j.marpetgeo.2025.107638","url":null,"abstract":"<div><div>Seismic data from the northern part of the West Siberian Basin and the Enisey-Khatanga Trough indicates the presence of up to 15 km-thick Paleozoic sediments underlying the Mesozoic overburden. This finding challenges the traditional notion that folded Paleozoic rocks constitute the economic basement of the basin. The Paleozoic section comprises evaporitic units, most likely of Ordovician age, which were deposited in troughs formed during the Early Paleozoic Uralian rifting. A reinterpretation of the geological structure suggests that salt tectonics has significantly influenced the subsurface architecture of these regions. Seismic evidence for salt diapirs includes (1) significant heights of salt structures (5 km or more), (2) seismic transparency, (3) minibasin tectonostratigraphic successions flanking the salt structures, and (4) radial fault systems in the overlying deposits. Additional evidence for the occurrence of salt diapirs includes magnetic, gravimetric, thermal, electrical, and topographic anomalies. Minibasin tectonostratigraphic successions suggest that diapirism began soon after salt deposition, preceding the onset of the Late Paleozoic compression. Far-field intracratonic deformations modified salt structures during the Mesozoic-Cenozoic, including extensional episodes in the Early Triassic and Early-Middle Jurassic and contractional episodes in the Late Triassic, Early Cretaceous, and the Late Cenozoic. These events led to folding of post-salt strata, which was accompanied by continuous differential compaction and Quaternary post-glacial rebound of diapirs. These processes amplified anticlines in post-salt Cretaceous reservoirs, which host giant gas accumulations.</div><div>The thick and thermally mature Paleozoic deposits include source rocks, which likely significantly contributed to the region's hydrocarbon potential. The upward migration of hydrocarbons through salt structures, from the deeply buried Paleozoic section into the Mesozoic overburden, provides a plausible explanation for the long-debated origin of the abundant gas content in Cretaceous deposits.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"183 ","pages":"Article 107638"},"PeriodicalIF":3.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145322318","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":"Intrasalt carbonates in the Estopanyà Salt Wall (South-Central Pyrenees): reservoir quality and implications for geothermal exploration in salt diapirs","authors":"Pedro Ramirez-Perez ,&nbsp;Gabriel Cofrade ,&nbsp;Jean-Pierre Sizun ,&nbsp;Juan D. Martín-Martín ,&nbsp;Mar Moragas ,&nbsp;David Cruset ,&nbsp;Anna Travé","doi":"10.1016/j.marpetgeo.2025.107646","DOIUrl":"10.1016/j.marpetgeo.2025.107646","url":null,"abstract":"<div><div>Stringers are disrupted rock bodies commonly enclosed within salt diapirs. Traditionally, they have been regarded as a risk factor in the energy exploitation of salt structures due to their heterogeneity and general sub-seismic scale, which hinder their detailed identification. Nevertheless, rock units in stringers may exhibit sufficient permeability and temperature to act as potential reservoirs, for instance, in geothermal energy. Despite this possibility, studies regarding the reservoir potential of intrasalt stringers remain scarce.</div><div>The well-exposed Estopanyà Salt Wall in the South-Central Pyrenees contains abundant Muschelkalk carbonate stringers, providing an excellent opportunity to study the geological controls on their reservoir properties. Four lithofacies within two stratigraphic intervals were identified. Depositional lithofacies (DLF-1 and DLF-2) preserve original rock textures, whereas alteration lithofacies (ALF-1 and ALF-2) result from intense brecciation, cementation, and dolomitization-dedolomitization affecting the depositional facies. Thermophysical analyses of 30 samples reveal limited variation in mineral density (2.61–3.00 g cm⁻³), bulk density (1.92–2.95 g cm⁻³), and thermal conductivity (2.37–3.48 W m⁻¹ K⁻¹), with the latter being primary controlled by rock mineralogy. In contrast, connected porosity (0.33–29.20 %), permeability (&lt;0.001–19.85 mD; &lt;10⁻¹⁸–10⁻¹⁴ m²), P-wave velocity (3.7–6.4 km s⁻¹ dry; 3.7–6.5 km s⁻¹ saturated conditions), and specific heat capacity (640–804 J kg⁻¹ K⁻¹) show greater variability. Property cross-plots indicate that porosity percentage and distribution are the main factors controlling the observed thermophysical behavior, which is ultimately linked to rock texture.</div><div>The area and scarce thickness of porous and permeable intervals (estimated at reservoir volumes of 0.14–4.6 km³), likely preclude the limited reservoir use of the studied stringers. However, petrographic evidence from them highlights interesting processes such as brecciation and dolomitization that may have enhanced the permeability and thermal conductivity in the past, while subsequent cementation and dedolomitization reduced reservoir quality. Accordingly, although current outcrop conditions show diminished reservoir potential, higher porosity-permeability values may be preserved in the subsurface.</div><div>Overall, this study establishes a conceptual model for the geological controls, limitations, and potential of intrasalt carbonates as unconventional reservoirs, providing comprehensive petrological and thermophysical data that can guide their exploration for geothermal production in salt diapir settings.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"183 ","pages":"Article 107646"},"PeriodicalIF":3.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145418206","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":"Seismic cycle-controlled hydrocarbon vertical migration through carbonates in the Ragusa Oil Field (SE Sicily, Italy)","authors":"Giovanni Barreca ,&nbsp;Salvatore Gambino ,&nbsp;Luca Smeraglia ,&nbsp;Andrea Billi ,&nbsp;Eugenio Carminati ,&nbsp;Giovanni Cassarino","doi":"10.1016/j.marpetgeo.2025.107640","DOIUrl":"10.1016/j.marpetgeo.2025.107640","url":null,"abstract":"<div><div>Hydrocarbon seepage at the Earth's surface provides crucial insights into subsurface petroleum systems. This study investigates the role of seismic cycle dynamics in controlling vertical hydrocarbon migration by studying the Ragusa Oil Field, a long-exploited petroleum district in the Hyblean foreland domain of south-eastern Sicily (Italy). Inspired by oil spilling in the area that followed a seismic sequence in February 2016, a multiscale structural analysis was undertaken to explore the relationship between fault activity and oil mobilization. This study integrates mesoscale structural measurements, microstructural analysis of bitumen-bearing fault breccias, and 3D Dilation Tendency modelling under paleo- and present-day stress conditions to build a dynamic model of upward hydrocarbon migration and seepage at the Earth's surface during the seismic cycle in carbonate-hosted normal faults in a foreland setting. Evidence from abandoned asphalt mines and active seep sites reveals both stratigraphic layer-impregnation and localized fault/fracture-controlled oil pathways. Field observation and Dilation Tendency analysis indicate that vertical hydrocarbon migration may predominantly occur by fractures instability during seismic rupture allowing overpressured fluids to migrate vertically, mainly at fault intersections. These findings highlight the role of seismic deformation in controlling fractures instability and transient permeability changes which, in turn, facilitate hydrocarbon mobilization and leakage. Calcite clast aggregates within hydrocarbon-filled voids observed during microstructural investigations confirm episodic, pressure-driven fluidization consistent with co-seismic mobilization. Stratigraphic evidence of repeated seepage events in Quaternary alluvial deposits supports a model of cyclic hydrocarbon migration linked to stress variations during the seismic cycle. The novelty of this paper is that we document an hydrocarbon seepage process associated with modern seismicity, filling the gap of previous observations of hydrocarbon seepage speculatively associated with fossil earthquakes without a direct cause-effect link.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"183 ","pages":"Article 107640"},"PeriodicalIF":3.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145364275","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":"Retraction notice to “Machine learning assisted reservoir characterization for CO2 sequestration: A case study from the Penobscot field, Canada Offshore” [Mar. Petrol. Geol. 169 (2024) 107054]","authors":"Satya Narayan ,&nbsp;Vijay Kumar ,&nbsp;Bappa Mukherjee ,&nbsp;S.D. Sahoo ,&nbsp;S.K. Pal","doi":"10.1016/j.marpetgeo.2025.107631","DOIUrl":"10.1016/j.marpetgeo.2025.107631","url":null,"abstract":"","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"183 ","pages":"Article 107631"},"PeriodicalIF":3.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733505","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":"Quantifying the effect of chlorite on reservoir quality and CO2 sequestration in deep saline aquifers from the permian tight sandstone reservoir in the ordos basin, China","authors":"Yaxin Shang ,&nbsp;Keyu Liu ,&nbsp;Ziyi Wang ,&nbsp;Bo Zhang","doi":"10.1016/j.marpetgeo.2025.107619","DOIUrl":"10.1016/j.marpetgeo.2025.107619","url":null,"abstract":"<div><div>Chlorite can strongly affect the quality of clastic sandstone reservoirs and may also impact the potential of geologic sequestration of CO₂ in deep saline aquifers. However, there is a lack of quantitative evaluation of the effect of chlorite on CO₂ sequestration in sandstones to date. Here we applied a suite of analytical techniques including petrographic and petrological analysis, X-ray diffraction measurement, petrophysical analysis, and CO₂-fluid-rock reactive-transport simulations to investigate the impact of chlorite on both reservoir quality and CO₂ geological sequestration in the Upper Permian sandstones in the northeastern Ordos Basin, China. Three types of chlorite are present in the reservoir sandstone: grain-coating, pore-throat-blocking, and pore-filling. Grain-coating chlorite sandstones feature thin chlorite wrapping on sand grain surfaces that effectively prevent quartz cementation, thus preserving good reservoir porosity and permeability. Pore-throat-blocking chlorite sandstones generally exhibit high porosity but low permeability with the thick chlorite coatings inhibiting quartz cement growth and preserving porosity while blocking pore throats and reducing permeability. Pore-filling chlorite sandstones are characterized by both low porosity and low permeability due to extensive chlorite filling of the pore spaces as matrix. Reactive transport simulations demonstrate that high-porosity and -permeability reservoir sandstones may not always be the most favorable sandstone type for CO₂ geological sequestration when considering the key geochemical sequestration mechanisms (<em>i.e.</em> dissolution and mineral trapping). When disregarding the impact of chlorite on reservoir quality, pore-filling chlorite sandstones, with their high chlorite content, are most suitable for CO₂ sequestration due to their greater capacity for trapping CO₂ via mineralization. However, when both chlorite abundance and reservoir quality factors are considered, pore-throat-blocking chlorite sandstones would possess the largest total CO₂ sequestration capacity.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"183 ","pages":"Article 107619"},"PeriodicalIF":3.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145270613","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":"Isotopic evidence for the origin and migration of methane and carbon dioxide in terrestrial mud volcano systems: Insights from carbon and hydrogen isotope fractionation","authors":"Li Zhang ,&nbsp;Xiangxian Ma ,&nbsp;Georgy Chelnokov ,&nbsp;Vasilii Lavrushin ,&nbsp;Yuxin Guo ,&nbsp;Wasim Sajjad ,&nbsp;Zhongping Li ,&nbsp;Guodong Zheng","doi":"10.1016/j.marpetgeo.2025.107649","DOIUrl":"10.1016/j.marpetgeo.2025.107649","url":null,"abstract":"<div><div>Mud volcano systems release methane (CH₄) and carbon dioxide (CO₂), which are not only potential energy resources but also key greenhouse gases influencing global climate change. However, the formation mechanisms and geochemical characteristics of gases emitted from mud volcanoes—shaped by both thermogenic and microbial processes—are still not well understood. In this study, representative terrestrial mud volcanoes from the Junggar Basin (Northern Tianshan) and the Kuban Basin (Northern Caucasus), were investigated through stable isotopes of CH₄–H₂O, CH₄–CO₂, and CO₂–DIC systems, aiming to elucidate water–gas interactions and gas generation pathways. The hydrogen isotopic compositions of CH₄–H₂O system reveal clear regional differences between Junggar and Kuban mud volcanoes. The Junggar samples are characterized by strongly depleted δD_CH4, and highly negative ΔD_(CH4–H2O) values, indicating extensive microbial overprinting under low-temperature conditions. In contrast, the Kuban samples exhibit a wider range of ΔD values, suggesting spatial variability in microbial influence, potentially limited by localized rapid gas ascent or open systems. Carbon isotope data reveal a mixed-origin pattern, with varying contributions from both thermogenic and microbial processes. A small number of samples (e.g., Western Tsymbaly) display isotopic characteristics consistent with microbial CO₂ reduction. In contrast, other samples exhibit isotopic discrepancies among CH₄, CO₂, and DIC, suggesting that CH₄ and CO₂ were influenced by different formation mechanisms or geochemical processes. Overall, methane in both regions has primarily thermogenic sources, but has undergone varying degrees of secondary microbial alteration in the shallow subsurface (e.g., through acetate fermentation or anaerobic methane oxidation). These findings support a model of thermogenic dominance with microbial overprinting. This study highlights the value of multi-parameter isotope approaches in unraveling the complex formation and transformation mechanisms of CH₄ and CO₂ in active mud volcano systems and provides valuable geochemical constraints for gas origin tracing and natural gas exploration.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"183 ","pages":"Article 107649"},"PeriodicalIF":3.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526188","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":"Characteristics of periodically active cold seep and gas hydrate systems in Krishna-Godavari offshore basin, India","authors":"Jin Qian ,&nbsp;Xiujuan Wang ,&nbsp;Jiapeng Jin ,&nbsp;Maheswar Ojha ,&nbsp;Nengyou Wu ,&nbsp;Ranjana Ghosh ,&nbsp;Kalachand Sain ,&nbsp;Zhen Liu","doi":"10.1016/j.marpetgeo.2025.107615","DOIUrl":"10.1016/j.marpetgeo.2025.107615","url":null,"abstract":"<div><div>In the Krishna-Godavari (K-G) offshore basin, India, a 130 m thick fracture-filling gas hydrate-bearing layer (GHBL), associated with near-seafloor paleo-cold seep activity, was identified during drilling and coring at Site NGHP-01-10 (Site 10). Our new analyses of drilling cores and pore-water show that authigenic carbonates and shells are present throughout the upper 200 mbsf at Site 10, with two separate intervals of high chloride concentrations up to 663 mM. It indicates a periodically active cold seep and relatively young hydrate system. This study combines core, well log and seismic data to gain insight into the fine characteristics and detailed formation process of such a thick paleo-cold seep and hydrate system. Seismic imaging of newly interpreted chimney-like structures, growth faults and multiple stacked mass transport deposits (MTDs) illustrates that the system is located within a geologically disturbed sediment zone. Synthetic seismogram-derived time-depth relationship between seismic and core data shows that multiple MTDs repeatedly control the paleo-cold seeps and further influence the hydrate. A new paleo-cold seep and hydrate system is identified southeast of Site 10, where seismic data reveal a buried vent characterized by a high amplitude reflection consistent with seafloor polarity, along with high density and velocity indicative of authigenic carbonates. These two thick systems probably formed in stages due to the clear stratifications on the seismic data, 2D anisotropic saturations and internal chimney-like structures. They are originated from diapirism and growth faulting, and their lateral extent depends on the fracture zone width within the anticline ridge. After formation, the process of hydrate recycling is triggered by the sedimentation and has led to the upward shift of the system. Our findings indicate that there exists a periodically active cold seep and gas hydrate system at Site 10. The activity of this periodic system can account for the formation of the multilayered or thick GHBL, and facilitate an understanding of the evolution of the paleo-cold seep found around the world. Although the cold seep at Site 10 is not active and the hydrate is currently only in the chloride diffusion stage, the underlying gas accumulation means that new cold seep and hydrate systems may form in the future.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"182 ","pages":"Article 107615"},"PeriodicalIF":3.6,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145219114","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":"Geochemical insights into authigenic pyrite formation in central Yellow Sea sediments: influence of sedimentary environment and microbial sulfate reduction","authors":"Yu Gu ,&nbsp;Xin Chang ,&nbsp;Xiting Liu ,&nbsp;Mingyu Zhang ,&nbsp;Yanfei An ,&nbsp;Guangchao Zhuang ,&nbsp;Houjie Wang","doi":"10.1016/j.marpetgeo.2025.107587","DOIUrl":"10.1016/j.marpetgeo.2025.107587","url":null,"abstract":"<div><div>Authigenic pyrite is a key archive of paleo-redox conditions and sulfur cycling in marine sediments, yet its formation mechanisms under variable marginal sea environments remain incompletely understood. This study investigates the formation of authigenic pyrite in Holocene sediments from the central Yellow Sea, focusing on its morphology, sulfur isotopes, and environmental controls. Pyrite formation is primarily constrained by the availability of reactive organic carbon, as revealed by total organic carbon–total sulfur relationships (C/S ratios) and reactive iron content. High C/S ratios suggest that the supply of organic matter, rather than the availability of sulfate or iron, plays the dominant role. Framboidal pyrite is the most common morphology. These framboids consist of tightly packed microcrystals, primarily octahedral and truncated octahedral in shape, indicating rapid precipitation under early diagenetic, low-oxygen, and low-energy conditions. The sulfur isotopes of pyrite (δ³⁴S_pyr, Vienna Canyon Diablo Troilite; V-CDT) range from −47.4 ‰ to −7.8 ‰, reflecting large fractionations associated with microbial sulfate reduction (MSR). The vertical δ³⁴S_pyr profile shows transitions from open- to closed-system MSR regimes, modulated by changes in sedimentation rate, freshwater input, and stratification linked to the Yellow Sea Cold Water Mass. These findings reveal the interplay between sedimentary environment, pyrite morphology, and sulfur isotope composition, offering insights into sulfur cycling in modern marginal marine settings and ancient analogues.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"182 ","pages":"Article 107587"},"PeriodicalIF":3.6,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144931635","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}