Marine and Petroleum Geology最新文献

{"title":"Characterizing multi-scale heterogeneities in shales: An innovative workflow and application to Paleogene lacustrine shales in the Subei Basin, eastern China","authors":"Zongguang Guo ,&nbsp;Keyu Liu ,&nbsp;Lingjie Yu ,&nbsp;Jie Chen ,&nbsp;Yuqi Wu ,&nbsp;Lei Chen ,&nbsp;Chao Liang","doi":"10.1016/j.marpetgeo.2025.107398","DOIUrl":"10.1016/j.marpetgeo.2025.107398","url":null,"abstract":"<div><div>Quantitative characterization of heterogeneous shales is crucial for identifying shale oil and gas sweet spots. However, there lacks methods that can be used to effectively characterize meso-scale (mm-dm) heterogeneities of shales including their compositions, structures and petrophysical properties which critically bridge the micro-to macro-scale heterogeneities. Here we propose a workflow to obtain two-dimensional representative elementary areas of heterogeneous shales through chemo-sedimentary facies analysis based on micro-XRF imaging at meso-scale. This workflow can guide sub-sampling for effective shale characterization at meso-scale and integrate micro-scale information from scanning electron microscopy with macro-scale wireline log data. To demonstrate the effectiveness of this workflow, we conducted a multi-scale characterization of mineral composition and pore structure heterogeneities on six representative lacustrine shales from the Subei Basin in eastern China. The mineral compositional heterogeneities of different lithofacies were found to be primarily influenced by paleo-water depth and seasonal climate changes, as determined through chemo-sedimentary facies analysis. Pore heterogeneities were further characterized using field emission scanning electron microscopy, low-temperature nitrogen adsorption, high-pressure mercury intrusion and fractal dimension analysis. Three distinct pore types (Type I, II, and III) were identified, with their complex relationships among mineral types, pore structures, and fractal dimensions elucidated. Type I pores exhibit H3-type hysteresis loops, Type II pores exhibit blended H2-type and H3-type hysteresis features, while Type III pores display a predominant H2-type hysteresis behavior. Heterogeneities of micropores, mesopores and macropores in shales are mainly determined by clay, carbonate and felsic mineral contents, respectively. The proposed workflow enables concurrent quantitative and <em>in situ</em> evaluation of heterogeneous attributes pertaining to lacustrine shales, providing valuable insights for the exploration of lacustrine shale oil and gas.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"178 ","pages":"Article 107398"},"PeriodicalIF":3.7,"publicationDate":"2025-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143834808","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":"Brine-saturated kaolinite mudrocks preserve capillary sealing to CO2 at high pressure and temperature","authors":"Mohamed M. Awad,&nbsp;D. Nicolas Espinoza","doi":"10.1016/j.marpetgeo.2025.107396","DOIUrl":"10.1016/j.marpetgeo.2025.107396","url":null,"abstract":"<div><div>Caprock sealing capacity is essential for carbon geological storage in saline aquifers and depleted oil and gas formations. Clay-rich caprocks and fault gouge are expected to hold buoyant CO₂ in the storage formation by capillary forces. However, all direct capillary sealing capacity measurements of clay-rich rocks to CO₂ were so far limited to pressures below ∼20 MPa and/or temperatures below 50 °C, typically lower than target storage conditions. This paper presents new results of brine absolute permeability, capillary CO₂ breakthrough pressure, and post-breakthrough CO₂ permeability for resedimented kaolinite clay plugs at fluid pressures greater than 41 MPa, temperatures of 60 °C and 80 °C, and mean effective stress of ∼6.8 MPa. The results show that breakthrough pressure (P_CO₂ - P_w) is always positive and remains in the interval between ∼ 1.4 MPa and 2.8 MPa within the range of pressure and temperature explored. Moreover, average post-breakthrough CO₂ relative permeability is ∼5 %. An additional test with a clay mixture representative of a shale from the North Sea, at similar pressure-temperature conditions held a differential pressure, i.e., no breakthrough, over three months with a maximum difference P_CO₂ - P_w = 5.71 MPa. Results and analysis support the water-wet properties of clays at high pressure and temperature and the resulting capillary sealing capacity to CO₂. These results support expectations that clay-rich caprocks are satisfactory seals for holding buoyant CO₂ via capillary forces. Results also suggest that if the sealing capacity is surpassed, clay-rich caprocks can limit advective flow because of their low CO₂ relative permeability and potential for resealing through snap-off.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"177 ","pages":"Article 107396"},"PeriodicalIF":3.7,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143776729","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":"Facies analysis of gravity-flow deposits from the Upper Cretaceous of the Alborz Mountains (northern Iran)","authors":"Hedieh Abbasian ,&nbsp;Mahboubeh Hosseini-Barzi ,&nbsp;Abbas Sadeghi ,&nbsp;Abdolhossein Amini ,&nbsp;Eduardo Garzanti","doi":"10.1016/j.marpetgeo.2025.107395","DOIUrl":"10.1016/j.marpetgeo.2025.107395","url":null,"abstract":"<div><div>Field studies of sedimentary successions complemented by petrographic analyses allow distinctions among sub-environments, even in the case of subtle differences in geometry, structure, and composition. In three apparently uniform sections of the coarse-grained siliciclastic K2b unit of Upper Cretaceous age exposed in the southern central Alborz Mountains (northern Iran), careful observations of texture, fabric, composition, and bed thickness have allowed the identification of eight petrofacies, twelve low-rank facies associations, and six high-rank facies associations. The coarse grain size of the K2b unit, the radial paleocurrent pattern indicated by grain orientation, along with the presence of hummocky and swaley cross-stratification, glaucony, Skolithos ichnofacies, and <em>Hedbergellidae</em> planktonic foraminifera suggest a fan-delta prograding onto a shallow shelf. Conglomerate layers, erosion surfaces, plane beds, and oriented grains point to diverse depositional mechanisms, including cohesive debris flows, hyperconcentrated flows, and turbidity currents. Sediment-gravity flows in the K2b unit, generated along the southern margin of the Proto-south Caspian basin, testify to both relative sea-level fall and tectonic uplift in mountainous source areas.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"177 ","pages":"Article 107395"},"PeriodicalIF":3.7,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143734754","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":"Seafloor thermal structures controlled by recent slope failure and fluid flow: An example from offshore SW Taiwan","authors":"Wei-Chung Han ,&nbsp;Liwen Chen ,&nbsp;Wu-Cheng Chi ,&nbsp;Hsieh-Tang Chiang ,&nbsp;Song-Chuen Chen ,&nbsp;Char-Shine Liu ,&nbsp;Chuen-Tien Shyu","doi":"10.1016/j.marpetgeo.2025.107394","DOIUrl":"10.1016/j.marpetgeo.2025.107394","url":null,"abstract":"<div><div>Ubiquitous bottom simulating reflections (BSRs) on seismic profiles indicate the presence of gas hydrates and free gases in both the active and passive margins offshore SW Taiwan. Detailed seafloor temperature measurements and modeling were conducted in offshore SW Taiwan gas hydrate provinces to investigate the thermal structure under dynamic gas hydrate systems. We performed seismic analysis, direct temperature measurements, and BSR-based thermal modeling to understand the seafloor thermal structures and subsurface fluid flow systems. First, seismic interpretation was applied to understand the BSR distribution and structural features in the gas hydrate provinces along the convergent plate boundary offshore SW Taiwan. Then, we compiled the 159 <em>in-situ</em> temperature measurements in marine sediments, and a regional heat flow map was proposed. After that, we use the sub-bottom depths of the widespread BSRs to derive seafloor thermal structures offshore SW Taiwan. Finally, by comparing the measured and BSR-based temperature fields, several interesting geological processes affecting the seafloor thermal structures are revealed. The distinct heating effects near the lower slope of the accretionary prism indicate active fluid flow along the thrust and décollement systems. In the upper slope, the seafloor thermal structure shows an overall low with local higher heat flow near the diapiric structures, implying that the diapirs may serve as active fluid conduits. Although few large-scale fault systems exist in the passive South China Sea (SCS) Slope, the upward fluid migration along normal faults, dipping strata, and gas chimneys contribute to intense local-scale seafloor heating. Apparent thermal nonequilibrium observed near the deformation front reveals a recent mass transport deposit (MTD) event with a volume of ∼0.8 km³. Our results present the geologically controlled seafloor thermal structures under the dynamic gas hydrate systems, which may give insights into the subsurface fluid flow, gas hydrate systems, and submarine geohazards.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"177 ","pages":"Article 107394"},"PeriodicalIF":3.7,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143734755","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":"Underestimated risks for application of hydraulic fracturing into hydrate exploitation: In the perspective of formation deformation and sand production","authors":"Peng Li ,&nbsp;Zhiqiang Fan ,&nbsp;Liang Zhao ,&nbsp;Chunlong Yang ,&nbsp;Kun He ,&nbsp;Dayong Wang","doi":"10.1016/j.marpetgeo.2025.107393","DOIUrl":"10.1016/j.marpetgeo.2025.107393","url":null,"abstract":"<div><div>Hydraulic fracturing in hydrate-bearing formation enhances reservoir permeability, thereby promoting gas production, but simultaneously compromises the mechanical strength integrity of the solid skeleton, amplifying risks of reservoir deformation, seafloor subsidence, and sand production. Despite these challenges, the interplay between hydraulic fracturing and such risks remains inadequately quantified, resulting in underestimation of exploitation risks. In this study, we developed a fully coupled thermal-hydraulic-mechanical-chemical model that incorporates sand production dynamics, validated against experimental data and numerical benchmarks. Using the Shenhu hydrate reservoir as a case study, we evaluated the effects of hydraulic fracturing (characterized by a fracture length of 5 m, a fracture permeability of 1 D, and a damage zone permeability of 50 mD) on long-term gas production, formation deformation, and sand production behaviors. Our analysis reveals that hydraulic fracturing increases cumulative gas production by 57 %, reaching 2.34 × 10⁶ m³ after 1000 days. However, it also triggers significant mechanical degradation: the volumetric strain in the damaged zone exceeds 2.5 %, which exacerbates formation collapse, inducing an additional 7 cm of seafloor subsidence, for a total of 21 cm and intensifying sand production to 903 m³, 2.4 times higher than production without fracturing. Further increases in fracture length beyond 5 m or fracture permeability above 0.1 D yield diminishing returns in gas production but exacerbates sand production. Enhancing the damaged zone's permeability from 25 mD to 75 mD increases gas production by 20 %, but also raises sand production by 49 % and seafloor subsidence by 4 cm.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"177 ","pages":"Article 107393"},"PeriodicalIF":3.7,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143725657","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":"Implications of carbon isotope fractionation of natural gas, pyrobitumen, and source rock on Sinian gas reservoirs evolution, central Sichuan Basin","authors":"Yishu Li ,&nbsp;Guangdi Liu ,&nbsp;Zezhang Song ,&nbsp;Mingliang Sun ,&nbsp;Xingwang Tian ,&nbsp;Dailing Yang ,&nbsp;Lianqiang Zhu","doi":"10.1016/j.marpetgeo.2025.107392","DOIUrl":"10.1016/j.marpetgeo.2025.107392","url":null,"abstract":"<div><div>Hydrocarbon reservoirs in ancient and deeply buried formations typically exhibit complex evolutionary histories. After experiencing high temperatures, pressures, and multiple types of secondary modifications, the geological information carried by hydrocarbons is superimposed and difficult to interpret. Methane carbon isotopes (δ¹³C) in the Sinian natural gas in the central Sichuan Basin are heavier than those of the reservoir solid pyrobitumen (SB) and are considered an ‘anomalous’ fractionation. Therefore, based on the abundant δ¹³C data of the source rock, SB, and natural gas, this study aimed to interpret the geological significance recorded by the ‘anomalous’ fractionation combined with the analysis of geological elements and the evolution process of the gas reservoir. The results showed that the combined contributions of multiple source rocks lead to differences in the original δ¹³C of crude oil in paleo-oil reservoirs. Among them, the slope of the paleo-uplift was closer to the Deyang–Anyue rift trough, where the δ¹³C of the main Cambrian source rocks was negatively biased, making the δ¹³C of the paleo-oil reservoirs more negative. During the late thermal evolution, deasphalting was caused by gas produced from oil cracking under high temperatures and pressures. In contrast, the adsorption of clay minerals and gas intrusion due to kerogen degradation in the source rocks had little effect on deasphalting. The δ¹³C values of the bulk SB precipitated by deasphalting were light and similar to those of the contemporaneous oil. However, the cracked gas with substantial negative δ¹³C produced in the early phase completely escaped as the reservoir pressure increased; the traps concentrated only the late cracked gas, which was isotopically heavier than all the SB produced in the different stages. This study provides new insights into the evolution of isotopic fractionation in ancient oil and gas systems involving oil cracking and phase transformation.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"177 ","pages":"Article 107392"},"PeriodicalIF":3.7,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143704765","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 characteristics of light hydrocarbons generated in thermochemical sulfate reduction: Results from three series of simulation experiments","authors":"Zhenyu Sun ,&nbsp;Jian Chen ,&nbsp;Wanglu Jia ,&nbsp;Qiang Wang ,&nbsp;Jie Xu ,&nbsp;Xin Li ,&nbsp;Jianghu Yang ,&nbsp;Ping'an Peng","doi":"10.1016/j.marpetgeo.2025.107388","DOIUrl":"10.1016/j.marpetgeo.2025.107388","url":null,"abstract":"<div><div>Thermochemical sulfate reduction (TSR) is an intense redox reaction that significantly alters the original hydrocarbons in deep reservoirs. Previous studies have shown that light hydrocarbons (LHs) could be generated as important products in certain stages of TSR. However, the geochemical characteristics of these TSR-derived LHs remain poorly investigated, and their differences from those of LHs generated by thermal cracking (TC-derived LHs) are unclear. A TSR simulation designed to generate LHs without the influence of TC can solve this problem. In this study, three TSR series were conducted using <em>n</em>-octadecane, <em>n</em>-dodecylbenzene, and heavy oil as initial hydrocarbon reactants in sealed gold tubes. The yield, molecular composition, and carbon isotopic characteristics of the generated LHs were systematically analyzed. Results indicated that the yield of TSR-derived light oils was considerable (243.90–326.48 mg/g HCs), broadly equivalent to that in TC. However, the generation process of TSR-derived LHs was significantly brought forward and occurred at lower maturities relative to TC. In terms of molecular composition, TSR facilitated the formation of <em>n</em>-alkanes and aromatics, while suppressing the generation of branched alkanes and cycloalkanes. This resulted in the compositional characteristics of TSR-derived LHs being distinct from those of TC-derived LHs. Additionally, TSR-derived LHs became increasingly enriched in ¹³C as TSR progressed. The observed enrichment (3.7 ‰–6.2 ‰) was greater than that in TC-derived LHs (&lt;3 ‰) but smaller than that in TSR-altered LHs, most of which were destroyed by TSR alteration (3–22 ‰). Most geochemical parameters of TSR-derived LHs did not provide reliable information on biological inputs, depositional environment, maturity, or later alteration. As a result, these parameters should be used cautiously in deep reservoirs where TSR is likely to occur. Moreover, the composition of the initial hydrocarbons influenced the generation of TSR-derived LHs. The long-chain paraffin group from the initial hydrocarbons breaks off and gradually evolves into LHs during the later stages of TSR, whereas the occurrence of aromatic rings leads to the earlier generation of aromatic-rich LHs. TSR-derived light oils represent a new hydrocarbon resource in deep basins, although they are less economical than TSR-unaltered oils. This study enhances our understanding of the generation, evolution, and typical geochemical characteristics of TSR-derived LHs, and offers valuable insights for evaluating light oil resources in deep basins.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"177 ","pages":"Article 107388"},"PeriodicalIF":3.7,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143704766","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":"Fracturing in basinal siliciclastic deposits of the Wolfcampian Alta Formation, Marfa Basin, west Texas","authors":"David A. Ferrill ,&nbsp;Kevin J. Smart ,&nbsp;Adam J. Cawood ,&nbsp;Daniel J. Lehrmann ,&nbsp;Giovanni Zanoni ,&nbsp;R. Ryan King","doi":"10.1016/j.marpetgeo.2025.107391","DOIUrl":"10.1016/j.marpetgeo.2025.107391","url":null,"abstract":"<div><div>The Wolfcampian Alta Formation represents 1700 m of deep-water siliciclastic deposits exposed in the Marfa Basin, the southwestern sub-basin of the Permian Basin complex of west Texas. These exposures are important outcrop analogs for the highly productive Wolfcamp Shale oil and gas reservoir of the Delaware and Midland Basins because they are of similar age, lithologies, and depositional environments. We present preliminary field data from outcrops of the Alta Formation in the southeast part of the Chinati Mountains, including lithostratigraphy, fracture characterization, and mineralogical analyses. Mesostructural deformation fabrics are dominated by up to four systematic sets of bed-perpendicular opening- mode fractures but also include rare bed-parallel opening-mode veins (beef), and occasional normal faults and thrust faults. Opening-mode fractures are generally bed-restricted and are interpreted to record a complex history reflecting changing extension direction at the time of fracturing in these sandstone and shale strata. Fracture dimensions mapped in a sandstone bedding pavement exposure show that length (parallel to bedding) to height (perpendicular to bedding) ratios for opening-mode fractures range from 0.13 to 38.56, with an average aspect ratio for all mapped opening-mode fractures of 4.84. Scanline surveys of a systematic NE-striking opening-mode fracture set show that fracture spacing is strongly correlated with mineralogy in both sandstone and shale lithologies, with a strong positive correlation for fracture spacing vs. clay content, and very strong negative correlations for fracture spacing vs. quartz, quartz + feldspar, and brittleness index. Bed thickness vs. fracture spacing data from scanlines show marked differences between sandstone and shale beds, with a very strong positive correlation for sandstone beds, a weak negative correlation for shale beds, and a very weak positive correlation – i.e. no correlation – for combined data. These results suggest that composition exerts a first-order control on opening-mode fracture abundance, and that bed thickness is likely a subordinate, or less important, controlling factor. These relationships can potentially be leveraged for mineralogy-based subsurface fracture prediction in comparable siliciclastic deposits.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"177 ","pages":"Article 107391"},"PeriodicalIF":3.7,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143740011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Changes in lake sedimentary environment and characteristics of organic matter enrichment under the influence of geological events: The lower Jurassic (Sinemurian-Toarcian) organic-rich shale, Sichuan Basin, Upper Yangtze Plate","authors":"Jiahao Kang ,&nbsp;Xingzhi Wang ,&nbsp;Fei Huo ,&nbsp;Deming Zeng ,&nbsp;Yue Li ,&nbsp;Zisang Huang ,&nbsp;Yiqing Zhu ,&nbsp;Bo Li ,&nbsp;Shengyang Xie ,&nbsp;Yuran Yang ,&nbsp;Yiming Yang","doi":"10.1016/j.marpetgeo.2025.107390","DOIUrl":"10.1016/j.marpetgeo.2025.107390","url":null,"abstract":"<div><div>Two sets of lacustrine organic-rich shale formations (Dongyuemiao and Da'anzhai members) have been developed in the Lower Jurassic (Sinemurian-Toarcian) in the Sichuan Basin of the Upper Yangtze Plate. The two strata have terrestrial sedimentary records of the Sinemurian-Pliensbachian boundary event (SPBE) and the Toarcian Oceanic Anoxic event (T-OAE). Based on the petrological and geochemical data, the paleoenvironment of lakes during the Dongyuemiao and Da'anzhai periods was reconstructed, and the organic matter enrichment characteristics under the influence of two geological events (SPBE and T-OAE) were systematically explored. From our analysis, it was indicated that two volcanic activities (the Central Atlantic Magmatic Province (CAMP) and Karoo Ferrar Large Igneous Province) triggered global geological events (SPBE and T-OAE) and global marine transgression during the Early Jurassic. As a result, the climate in the Sichuan Basin shifted towards dryness in the short term. During the middle of the Sinemurian period (Dong2 period), the Sichuan Basin was a freshwater lake formed under a warm-humid climate. The biological productivity of lakes is high, in terms of terrestrial debris input, and has an oxic bottom water environment. Under the influence of climate, higher biological productivity is the key to controlling the enrichment of organic matter. During the late Sinemurian period (Dong1 period), the greenhouse gas emissions from the Central Atlantic Magmatic Province (CAMP) caused the transformation of the climate in the Sichuan Basin into semi-dry to semi-humid. These changes induced a marine transgression in the eastern part of the basin. However, the impact of marine transgression on the enrichment of organic matter was limited, and the enrichment of organic matter still depends on biological productivity. During the Toarcian period (Da'anzhai period), the continuous eruption of the Karoo Ferrar Large Igneous Province caused the climate of the basin to transform into semi-dry during the maximum flooding period. This effect may have triggered the entire basin's marine transgression. High salinity, deeper bottom water, and dyoxic environments greatly promote the preservation of organic matter.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"177 ","pages":"Article 107390"},"PeriodicalIF":3.7,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143681241","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":"Campanian-Maastrichtian evolution of sedimentary systems during the final stages of an epeiric sea —La Luna Sea— in eastern Colombia: Processes, spatio-temporal variability, and depositional controls","authors":"Carlos A. Giraldo-Villegas ,&nbsp;Francisco J. Rodríguez-Tovar ,&nbsp;Sergio A. Celis ,&nbsp;Andrés Pardo-Trujillo","doi":"10.1016/j.marpetgeo.2025.107385","DOIUrl":"10.1016/j.marpetgeo.2025.107385","url":null,"abstract":"<div><div>Epeiric seas were widespread during the Cretaceous, associated with global sea-level rise. Their stratigraphic record, controlled mainly by eustasy, tectonic and climatic factors, resulted in the accumulation of important hydrocarbon source and reservoir rocks. In the NW of South America-Colombia, an epeiric sea established in the Early Cretaceous—knows as La Luna Sea in the Late Cretaceous—, bounded by a volcanic arc to the western side and by the Amazonian Craton to the east, was progressively filled during the Campanian-Maastrichtian, being these latest Cretaceous deposits important hydrocarbon reservoirs for conventional petroleum systems. In the Campanian-early Maastrichtian period the western side and the central part of the basin had a normal shoreface profile, dominated by pelagic and wave sedimentation processes, while a delta profile dominated by fluvial processes characterized the eastern side. During the late Maastrichtian, directly related to the accretion of western Caribbean terranes, transitional and continental environments dominated by fluvial processes were established on both sides of the basin, suggesting changes in geomorphological-topographic and drainage system characteristics of the emerged areas, leading to the filling of the epeiric basin. The distribution of the deposits was controlled by allogenic processes: tectonism associated with the growth of the proto-Central Cordillera, the global eustatic level, and in minor degree by autogenic processes such as channel avulsion, bottom and longshore currents, and high productivity events. These processes and their variable temporal and spatial influence were responsible for the different types of deposits on either side of the basin, which had a direct impact on the establishment of macrobenthic communities, also providing new exploration ideas related to the reservoirs.</div><div>Comparisons suggest that the size of the receiving and emerged zones plays an important role in the distribution and arrangement of deposits along and across the basin, related to the nature of the internal processes involved in sediment redistribution.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"177 ","pages":"Article 107385"},"PeriodicalIF":3.7,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143681242","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}