Marine and Petroleum Geology最新文献

{"title":"Structural evolution of the Handun salt diapir, Zagros fold and thrust belt, southern Iran","authors":"","doi":"10.1016/j.marpetgeo.2024.107172","DOIUrl":"10.1016/j.marpetgeo.2024.107172","url":null,"abstract":"<div><div>The Fars region, in the Zagros fold and thrust belt, hosts a wide range of diapirs piercing over 10 km of stratigraphic sequence. Comprising Precambrian to Early-Cambrian Hormuz Salt, these diapirs exhibit a prolonged history of evolution. Outcrop evidence for understanding the diapir deformation history is mostly limited to the Cenozoic contractive phase, and the seismic data lacks the necessary quality for an exhaustive understanding of the deepest structure's geometries. Through regional and field evidence we unravel the Handun salt structure evolution and propose a sequential restoration to describe the key deformational events. Our study presents a field-based novel regional balanced cross-section and a 3D-geological model, and addresses the role of structural inheritances and the position of the Handun diapir with respect to the decupled basement. The performed field studies describe folds and unconformities related to Cenozoic halokinetic sequences with exceptional clarity. It was possible to observe changes of the diapir activity along the structure and provide field evidence for the relative timing and kinematics of primary and secondary welding. Finally, our data suggest that the Handun diapir formed in the early Paleozoic above the shoulder of a basement extensional fault, and was partially translated above its southern hanging-wall during the shortening. In the Paleocene a sustained ratio of salt rise rate was enhanced by the Zagros/Oman contraction. In response to the Oligocene continental collision, the diapir was profusely supplied with salt, which flared upward to form overhangs. Since the middle Miocene the salt supply slowly depleted, with the diapiric walls remaining near the surface but tapering upward, probably due to primary welding or increased sedimentation. Secondary welding occurred post-Pliocene in the last stages of the diapir evolution with consequent development of a secondary minibasin.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142529211","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":"Seismic stratigraphy and petroleum prospectivity in the Northern Rovuma Basin, offshore Tanzania","authors":"","doi":"10.1016/j.marpetgeo.2024.107173","DOIUrl":"10.1016/j.marpetgeo.2024.107173","url":null,"abstract":"<div><div>The upper slope area of the Northern Rovuma Basin has been poorly studied and little is known about its development and petroleum prospectivity. Interpretation of wellbore, 2D and 3D seismic reflection data in this area has allowed identification of seismic features reflecting key factors for understanding the development of the Cretaceous-Holocene stratigraphy and distribution of petroleum system elements. Our results show that infill of sediment into the basin was due to an interplay of three major factors. These are the sea level variations, extensional tectonics and sediment gravity flows. The Miocene and Pleistocene-Holocene tectonic events triggered gravity flows that supplied sediments to the basin. The resultant deposits include slides, slumps, debrites and turbidites some of which contain potential reservoirs that are interpreted to have been charged by the Permo-Triassic Karoo shales and Cretaceous-Cenozoic source rocks. These reservoirs are contained in both stratigraphic and structural traps with localized combinations in some places, and are encased by deep marine shales. Some of the potential reservoirs are positively inverted and compartmentalized, and they contain several bright and flat spots suggesting hydrocarbon accumulations within the Miocene and Oligocene intervals. It has also been revealed that major gravity flows and bottom currents, that supplied and distributed sediment to the basin, were confined in three long-lived channelized systems that were initiated during the Cretaceous (due to rapid regression), and the Oligocene and Pleistocene periods (due to rapid uplift). The channels migrated toward the southeast, with some shift toward the northeast, and had overall northeast traverse direction perpendicular to the shoreline. The reported gravity flows eroded previously deposited sediment in most places causing several unconformities in the whole Cretaceous-Holocene stratigraphy. Seismic stratigraphic interpretation and facies analysis have proved useful in the identification of key petroleum system elements and improve understanding of sedimentary fill evolution of the study area.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142529210","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":"Influence of Triassic and Jurassic arc magmatism in Lower Jurassic Sierra de Santa Rosa Formation, northwestern México: Constraints from geochemistry and U-Pb geochronology","authors":"","doi":"10.1016/j.marpetgeo.2024.107168","DOIUrl":"10.1016/j.marpetgeo.2024.107168","url":null,"abstract":"<div><div>The Permo-Triassic and Lower Jurassic sedimentary succession of the El Antimonio Group in northern Sonora, Mexico is inferred to be deposited in a forearc basin and its age has been constrained by fossil assemblages and detrital zircon geochronology. In this work, petrography, geochemistry and detrital zircon U-Pb geochronology were undertaken on the Sierra de Santa Rosa Formation, the younger unit of the El Antimonio Group in the locality of the Sierra del Álamo, to constrain its tectonic setting, age, source area paleoweathering, and provenance. Sandstone of Sierra de Santa Rosa Formation is petrographically classified as arkose. The elemental ratios, REE patterns and Eu anomaly, as well as bivariate and ternary plots suggest igneous felsic sources subjected to weak to moderated chemical weathering under arid climatic conditions for detritus of the Sierra de Santa Rosa Formation. Detrital zircon U-Pb geochronology of seven sandstone samples of this unit record main populations of Proterozoic age (58% of the total grains) with age peaks at 1.68. 1.39 and 1.14 Ga and Triassic age (31% of total grains) with age peak at 219 Ma, and subordinate groups of Paleozoic, Jurassic and Archean ages. Main sources for the zircon grains are the regional nearby igneous-metamorphic Proterozoic basement rocks, recycled detritus from the Proterozoic and Paleozoic sedimentary cover, and the Permo-Triassic and Jurassic continental magmatic arcs of southwestern North America. The detrital zircon U-Pb geochronology of the dated samples allows to establish Sinemurian to early Toarcian maximum depositional ages for the Sierra de Santa Rosa Formation in the locality of the Sierra del Álamo.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142560809","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":"Tectono-sequence evolution of an extensional strike-slip composite basin, a case study of the Miaoxi'nan sub-sag in the eastern Bohai Bay Basin","authors":"","doi":"10.1016/j.marpetgeo.2024.107170","DOIUrl":"10.1016/j.marpetgeo.2024.107170","url":null,"abstract":"<div><div>The significance of tectonics in shaping sequence stratigraphy within continental rift basins, especially those with extensional strike-slip composite characteristics, cannot be overstated. These basins, often repositories of rich oil and gas reserves, are defined by their intricate fault systems and dynamic tectonic interplay. Despite their economic importance, the tectono-sequence characteristics of these basins remain underexplored, affecting the understanding and prediction of petroleum systems. This study presents a comprehensive tectono-sequence analysis of the Miaoxi'nan sub-sag in the eastern Bohai Bay Basin, a continental lacustrine sag intersected by the eastern branch of the Tan-Lu fault zone. By integrating extensive 3D seismic data, wireline logs, and previous research, we establish a detailed tectono-sequence framework and unravel the complex interplay of geometric and kinematic characteristics within the extensional strike-slip fault system that governs the evolution of the basin. Our investigation reveals a multi-tiered sequence stratigraphic structure comprising two first-order, 4 s-order, and seven third-order sequences. The west sub-branch of the East branch of the Tan-Lu fault zone (EB-TLFZ) is identified as a strike-slip fault with a predominantly south-north strike, while the east sub-branch exhibits characteristics of a persistent tension-shear strike-slip fault zone. The study also shows a transitional fault strike of the rifting system from a multi-directional orientation at the base to a northeast-northeast-east direction, corresponding with different tectonic stages that have directed fault activities and sedimentary deformation. Additionally, both the extensional and strike-slip fault systems of the sag have experienced segmental growth evolution, influencing the westward and northward migration patterns of the basin's depocenter and subsiding center. Overall, the sequence development within the Miaoxi'nan sub-sag is predominantly regulated by the first- and second-order extensional faults, with the EB-TLFZ sub-branch faults providing further adjustment. This study provides vital insights into the tectono-sequence dynamics of extensional strike-slip composite basins, with implications for future hydrocarbon exploration and exploitation.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142529294","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":"Depositional architecture and evolution of Quaternary submarine canyon-fan system in the Baiyun Sag of the Pearl River Mouth Basin, northern South China Sea","authors":"","doi":"10.1016/j.marpetgeo.2024.107167","DOIUrl":"10.1016/j.marpetgeo.2024.107167","url":null,"abstract":"<div><div>Submarine canyons in the shelf margin usually serve as essential conduits for delivering sediments to slopes and basins and coevally develop turbidite reservoirs within deep-water fan systems. To understand the control of the evolution of the canyon-fan system, we focused on Quaternary deep-water depositional systems imaged in 3D seismic reflection data covering the lower reaches of the canyons and the base of the slope in the Baiyun Sag, on the northern margin of the South China Sea. By analyzing seismic facies tied to seismic attribute maps and time-thickness variations, three main seismic units were interpreted and described with markedly different geomorphologies and facies assemblages. Variations in the depositional architecture of the fan system recorded changes in sediment conditions during the Quaternary. The evolution of the Quaternary canyon-fan system can be summarized in three stages. Stage 1 is characterized by fan complexes with backstepping and stratigraphic onlapping against the erosional base, indicating a reduction in sediment supply due to rapid transgression during the Early Pleistocene. During Stage 2, the sediment supply decreased to its lowest rate, producing elongate-shaped turbidite complexes and a high proportion of hemipelagic deposits. In contrast, stage 3 was expressed by canyon-fan systems with downlapping stratigraphy resulting from the enhancement of sediment input during shelf margin/slope progradational intervals. The Quaternary canyon-fan system evolution was controlled not only by the rapid transgression but also by the efficiency of the sediment transfer mechanisms. Although higher rate of sediment supply occurred during stage 1, the dominant canyon-direct fed systems at this stage had highly efficient sediment transfer mechanisms, generating thicker and larger canyon-fan systems compared to stage 3. During stage 3, the progradation-direct-fed system became the primary sediment transport pattern causing sediment to mostly accumulate on the slope and reduce sediment delivery to the basin floor. Our results indicate that the distribution of gas hydrate accumulation is strongly associated with the depositional pattern of turbidites within the Lower Pleistocene succession.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142537974","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":"Molecular and carbon isotopic geochemistry of oils with different fluorescence color from the Upper Jurassic Qigu formation and oil accumulation process in Yongjin area, Junggar Basin in China","authors":"","doi":"10.1016/j.marpetgeo.2024.107163","DOIUrl":"10.1016/j.marpetgeo.2024.107163","url":null,"abstract":"<div><div>The Yongjin area, located in the middle of the Junggar Basin, is an important oil-producing region. Its major oil-producing formation is the Upper Jurassic Qigu Formation, which has experienced multiple oil-charging events that have resulted in oils with various fluorescent colors. However, the source of oils from the Qigu Formation is currently debated. As exploration and development progressed, the productivity of the Qigu Formation was observed to vary owing to oil viscosity differences. Conventional extraction methods can only be used to obtain a mixture of fluorescing oils of different colors, making it difficult to analyze the properties of oils that charge during different periods. Using microscopy to observe fluorescence the characteristics of oil in various samples were analyzed. Then, accelerated sequential extraction was used to separate the oils with different fluorescent colors (Groups I–IV). Through GC-MS (gas chromatography), GC-IRMS (gas chromatography-mass spectrometry), FT-IR (fourier transform infrared spectroscopy), and fluid inclusion observations and measurements, in conjunction with the geological context, the sources of oils from different charge periods and genesis of heavy oil were determined and the process of oil accumulation was reconstructed. Three stages of oil charging were identified: (1) During the Middle to Late Jurassic, low-mature and mature oil from the Lower Permian Fengcheng Formation and a low quantity of low-mature oil from the Middle Permian Lower Wuerhe Formation charged the Qigu Formation. These oils underwent notable biodegradation and oxidation, with some captured by inclusions (Group III) for preservation. (2) During the Late Cretaceous to Early Paleogene, mature oil from the Wuerhe Formation charged the Qigu Formation. This oil mixed with early oil that was not captured by the inclusions, resulting in the formation of black-brown fluorescing oil (Group IV) and yellow fluorescing inclusion oil (Group II). (3) From the Late Paleogene to the present, highly mature condensates from the Lower Wuerhe Formation charged the Qigu Formation. The oil mixed with early oil to generate yellow-brown (Group II) and blue-white (Group I) fluorescing oils. Low-mature and mature oil from the Fengcheng Formation charged the Jurassic reservoirs and underwent secondary alteration, whereas high-mature oil and gas did not. These oils likely predominantly accumulated in reservoirs between the Fengcheng and Lower Wuerhe formations. Although the Jurassic source rocks began to generate oil, this oil did not migrate upward to the Qigu Formation, indicating that the conventional and unconventional reservoirs under the Jurassic Qigu Formation have exploration potential.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142579075","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":"Do red marine carbonates represent oxic environments? New understanding from the Upper Ordovician marine limestone in Tarim Basin, China","authors":"","doi":"10.1016/j.marpetgeo.2024.107166","DOIUrl":"10.1016/j.marpetgeo.2024.107166","url":null,"abstract":"<div><div>Marine red beds (MRBs), typically colored by Fe- and Mn-rich minerals, are often interpreted as indicators of bottom water oxygenation. However, their continuous formation requires long-term input of aqueous derived Fe-Mn oxides and/or stable sources of Fe²⁺ and Mn²⁺ ions, challenging the traditional concept of “red equals oxic environment.” This study investigates two coeval Upper Ordovician Sandbian MRB carbonate intervals in the Tarim Basin. Previous studies attributed the pigment origin to hematite. Th/U values and total rare earth element and yttrium (REY) contents increased in the MRB interval, indicating a terrestrial source of iron. Hematite was observed within the intercrystal pores of calcite precipitating from porewater, consistent with high Ni_carb abundance and MREE-enriched bulge pattern in the red intervals. Both sections exhibit high Fe_carb and Mn_carb, pointing to substantial reductive dissolution of Fe and Mn oxides. Simulation shows that isotopic discrimination (Δ¹³C) between carbonate and organic carbon could be biased by increasing benthic Fe-Mn flux, leading to decreased Δ¹³C values in MRB intervals. Ce/Ce∗ values in the high-Mn_carb interval reflect the releasing of Ce by reductive dissolution of Mn oxides. The commonly used carbonate-based redox proxy I/(Ca + Mg) ratio is correlated positively with Mn_carb in the shallower section and with TOC in the deeper section, while it is negatively correlated with TOC in the shallower horizon, suggesting that iodine behavior may be influenced by adsorption and releasing of Mn hydro-oxides and organic matter besides oxygen contents. This study links MRB coloring to Fe and Mn mineral cycling in pore water through reductive dissolution and oxidative precipitation, and highlights potential biases of carbonate-based redox proxies that might be susceptible to other electron acceptors/donors such as Fe-Mn oxides and organic matter, in addition to free oxygen in seawater.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142529212","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":"Coupled evolution of basin structure and fluids recorded by microfractures: A case study of deep-buried ordovician in the tarim basin","authors":"","doi":"10.1016/j.marpetgeo.2024.107161","DOIUrl":"10.1016/j.marpetgeo.2024.107161","url":null,"abstract":"<div><div>The fluid activity in the deep strata of sedimentary basins is commonly related to tectonic activity, and the cements filled in fractures are a good carrier for the tectonic-fluid coupling evolution. Compared to macrofractures, microfractures have characteristics of high frequency and easy identifiable periods. Abundant microfractures infilled by carbonate cements (MCCFs) developed in carbonates of the Ordovician Yingshan and Yijianfang formations in the platform basin area of the Tarim Basin. Based on the study of petrology, U-Pb dating, and geochemical characteristics, this study determined the stages of MCCFs and clarified the tectonic-fluid coupling evolution process recorded by MCCFs in the study area. The formation order of these MCCFs is D1, C1, C2, D2, C3, and C4. The precipitation times of MCCFs have a good correspondence with orogeny around the Tarim Basin and active times of strike-slip faults in the platform basin area. The six stages of MCCFs in the Ordovician Yingshan and Yijianfang formations in the SLU recorded the tectonic-fluid coupling evolution process of concentrated seawater in the late Middle Ordovician, meteoric water at late Ordovician, organic acids during the Silurian, Mg-rich hot brine at the end Devonian-early Carboniferous, and magmatic hydrothermal fluids during the Permian. This not only indicates a close connection between fluid activity and tectonic activity in sedimentary basins, but also confirms that the formation of MCCFs in carbonate formations is closely related to regional tectonic-fluid coupling activities. This study provides a good example for studying macro scale tectonic-fluid coupling activities in basins using microfractures.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142537973","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":"Numerical simulation for subsidence control in CO2 storage and methane hydrate extraction","authors":"","doi":"10.1016/j.marpetgeo.2024.107160","DOIUrl":"10.1016/j.marpetgeo.2024.107160","url":null,"abstract":"<div><div>Gas hydrates are increasingly viewed as a promising alternative to traditional fossil fuels. However, their extraction process poses risks to structural integrity, potentially causing significant subsidence. In this study, we developed a Thermo-Hydro-Mechanical-Chemical (THMC) model to analyze the impact of gas hydrate extraction on seabed subsidence. Our investigation focused on the influence of bottom hole flowing pressure, initial hydrate concentration, gas saturation, permeability, porosity, and rock thermal conductivity on subsidence during gas hydrate extraction via depressurization.</div><div>The results show that seabed subsidence is affected by various factors such as bottom hole flowing pressure, initial hydrate concentration, gas saturation, permeability, porosity, and rock thermal conductivity. It was noted that significant subsidence is associated with low initial hydrate concentration, high permeability, porosity, low gas saturation, low rock thermal conductivity, and a notable pressure drop of 79.31%.</div><div>To address this issue, we propose a seabed subsidence mitigation strategy involving CO₂ injection. This approach not only safeguards offshore infrastructure and coastal communities but also helps reduce CO₂ emissions, aligning with global climate change mitigation efforts. In our model, CO₂ injection occurs in the subsurface reservoir at the interface between the free water zone and hydrate-bearing formations. The CO₂ hydrates formation process releases heat, which dissociates methane hydrates, allowing the methane to be replaced by CO₂ molecules and move towards the production well.</div><div>Our analysis reveals that increasing injection temperature and rate significantly reduces subsidence. Additionally, the range of investigated injection pressures, which included pressures equal to and more than double the initial reservoir pressure, showed inconsequential impacts on seabed subsidence.</div><div>The effectiveness of subsidence reduction is significantly enhanced by injecting a CO₂/N₂ mixture compared to pure CO₂ injection. The most substantial reduction in subsidence occurred when a mixture of CO₂ and N₂ in a 50/50 vol/vol ratio was injected at a high rate.</div><div>These findings offer crucial insights for optimizing the efficiency and control of gas hydrate extraction methods. They emphasize the importance of employing balanced injection strategies to minimize environmental risks and ensure sustainable energy extraction.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142529228","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 rare earth elements and yttrium (REY) geochemistry of the upper Carnian (Upper Triassic) carbonates from northwestern Sichuan Basin (South China)","authors":"","doi":"10.1016/j.marpetgeo.2024.107164","DOIUrl":"10.1016/j.marpetgeo.2024.107164","url":null,"abstract":"<div><div>Rare earth elements and yttrium (REY) serve as valuable tracers of the geochemical properties of paleo-seawater and diagenetic processes. Four different carbonate components, ooids, microbalites, cements and brachiopods, from upper Carnian (Upper Triassic) of the northwestern Sichuan Basin were analyzed for REY geochemistry. Petrographic and cathodoluminescence analyses were employed to identify diagenetic features. The bright luminescent microspar calcite cement, ooids and the microbialites from the lower part of Qingyangou (HWQ) section exhibit bell-shaped REY_SN patterns. Microbialites from the upper part of HWQ section have relatively high REY concentrations with a flat REY_SN pattern. The high content of ΣREY and terrigenous elements (e.g., Al, Zr, Th) in ooids and microbialites reflect the input of terrigenous clastic in the northwestern Sichuan Basin during Late Carnian. Articulated terebratulid brachiopods in the study area display a generally modern seawater-like REY_SN pattern. However, this pattern may be influenced by the presence of sparry cement that has infilled the cracks and punctae of the brachiopod shells. The ooids, microbalites, cements and brachiopods are unsuitable for reconstructing the REY characteristics of Carnian seawater in the northwestern Sichuan Basin due to diagenetic alteration and terrigenous input. This study also highlights the necessity of thoroughly evaluating carbonate components for diagenetic effects and terrigenous contamination when employing them for REY characteristic reconstruction.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142529295","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}