Organic Geochemistry最新文献

{"title":"Diamondoids, biomarkers, and chemofacies: Uniting insights on hydrocarbon maturation and migration in the Cline Shale, Midland Basin","authors":"Maram AlSaif ,&nbsp;Ibrahim Atwah ,&nbsp;Mauro Becker ,&nbsp;J. Michael Moldowan ,&nbsp;Alex Zumberge ,&nbsp;Franco Marcantonio","doi":"10.1016/j.orggeochem.2025.104953","DOIUrl":"10.1016/j.orggeochem.2025.104953","url":null,"abstract":"<div><div>Basinal mudrocks within the Wolfcamp Group of the Midland Basin, including the Cline Shale (Wolfcamp-D) interval, have proven to be prolific producers of oil and gas. However, predicting hydrocarbon distribution within the Cline Shale remains challenging due to its complex lithological heterogeneity and geochemical variability. In this study, molecular techniques and chemometrics were applied to address this challenge by: (1) characterizing the chemo-stratigraphically distinct depositional units of the Cline Shale, (2) understanding the role of lithological facies in hydrocarbon distribution, and (3) correlating produced-oil samples with the most productive zones within the Cline Shale.</div><div>Results reveal that the Cline Shale is dominated by marine-derived organic matter, with minimal terrigenous input. The sediments, currently in the peak-to-late oil window, exhibit distinct variations in redox conditions, paleoproductivity, and organic matter preservation across the Upper, Middle, and Lower intervals. Biomarkers such as terpanes, hopanes, and steranes highlight these variations. Further analysis using Quantitative Diamondoid Analysis (QDA) indicates notable differences in maturity and hydrocarbon cracking that cannot be explained solely by burial depth (∼300 ft difference). The highly mature oil in the Upper Cline appears to have been generated locally, whereas condensate in the Lower Cline is likely the result of lateral migration from deeper, more mature intervals. Quantitative Extended Diamondoid Analysis (QEDA) supports this by correlating oil samples from a nearby well to extracts from siliceous mudstones in the Upper Cline.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"203 ","pages":"Article 104953"},"PeriodicalIF":2.6,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143508832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 ultra-deep natural gases","authors":"Mingming Jiang ,&nbsp;Quanyou Liu","doi":"10.1016/j.orggeochem.2025.104964","DOIUrl":"10.1016/j.orggeochem.2025.104964","url":null,"abstract":"<div><div>As a clean energy source, natural gas occurs at various depths. Natural gas exploration targets have shifted from shallow to ultra-deep reservoirs. Despite the considerable potential of ultra-deep exploration, its development remains limited. To accelerate and improve the exploration of ultra-deep natural gas, it is essential to thoroughly understand the characteristics and origins. Analyzing the geochemical characteristics of both hydrocarbon and non-hydrocarbon gases from ultra-deep reservoirs (depth &gt; 6 km) across various global basins helps identify and classify their characteristics and origins. These gas pools typically contain helium in concentrations below 0.02% or is absent, with hydrogen generally below 2%, indicating that ultra-deep reservoirs may not serve as significant reservoirs for He and H₂. For hydrocarbon gas genesis, thermogenesis is predominant, with illustrative examples from different basins. Concerning CO₂ origins, inorganic processes such as thermochemical sulfate reduction (TSR) and magmatic CO₂ are prevalent, while organic and mixed origins, including organic matter degradation, are less common. The primary origin of H₂S is TSR, with the Mississippi Salt Basin being an exception due to possible contamination from inorganic volcanic gases interacting with hydrocarbon accumulations. Nitrogen’s origin is mainly related to the thermal evolution stage of source rocks. Understanding these gas characteristics provides valuable theoretical insights, which can guide the future exploration and development of ultra-deep natural gas and non-hydrocarbon gases.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"203 ","pages":"Article 104964"},"PeriodicalIF":2.6,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143464516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long chain n-alkanes in lake sediment track differences in adjacent land vegetation.","authors":"Bowen Xiao ,&nbsp;Dënë Cheecham-Uhrich ,&nbsp;David C. Eickmeyer ,&nbsp;Linda E. Kimpe ,&nbsp;Vilmantas Prėskienis ,&nbsp;E. Henriikka Kivilä ,&nbsp;Meiling Man ,&nbsp;Myrna J. Simpson ,&nbsp;Irena Creed ,&nbsp;Milla Rautio ,&nbsp;Jules M. Blais","doi":"10.1016/j.orggeochem.2025.104934","DOIUrl":"10.1016/j.orggeochem.2025.104934","url":null,"abstract":"<div><div>We conducted an analysis of <em>n</em>-alkanes, lignin-derived phenols, and other sediment markers from 19 lakes across four ecoregions in Saskatchewan, Canada, spanning from Prairie Grassland to Boreal Upland. Our goal was to establish whether these biomarkers relate to different ecoregions and land cover types (herbaceous plants vs trees) in the catchments of these lakes. Our findings revealed a significant inverse correlation between the proportion of herbaceous plants to trees in a lake’s catchment and the proportion of aquatic <em>n</em>-alkanes <em>P</em>_aq (C₂₃ + C₂₅)/(C₂₃ + C₂₅ + C₂₉ + C₃₁) indicating that aquatic plants contributed proportionally more to sedimentary <em>n</em>-alkanes when the catchments were mostly in Boreal forest. We also observed significant positive correlations between the proportion of herbaceous plants to trees in a lake’s catchment and the <em>n</em>-alkane composition ratios C₃₁/(C₂₇ + C₃₁) and C₃₁/(C₂₇ + C₂₉ + C₃₁), reflecting higher relative inputs of C₃₁ from herbaceous vegetation. These findings suggest that these ratios could potentially be utilized to infer historical land cover composition based on dated sediment records. Moreover, variations in the C₃₁/(C₂₇ + C₃₁) alkane ratio were observed among ecoregions, particularly between Prairie Grassland and the forest-dominated areas. We found no correlations between chlorophyll-<em>a</em> concentrations in lake water and the above-mentioned <em>n</em>-alkane ratios in sediment, suggesting that these ratios primarily reflect land cover composition rather than autochthonous production in the lakes. Additionally, the C/N ratio and δ¹³C were not effective in distinguishing ecoregions or land cover composition, likely due to influences from algal production and perhaps agricultural activities in surrounding farmland. In contrast, lignin-derived phenols in sediments showed relatively little association with their respective ecoregions and appeared to be influenced by decomposition as evidenced by high ratios of carboxylic acids relative to aldehydes (Ad/Al). Overall, our research highlights the potential of <em>n</em>-alkanes as biomarkers for tracking distinct land cover types due to their strong associations with the proportion of grasses and trees.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"202 ","pages":"Article 104934"},"PeriodicalIF":2.6,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Comparing lipid extraction methods on lake sediments without dichloromethane","authors":"Aaron F Diefendorf","doi":"10.1016/j.orggeochem.2024.104919","DOIUrl":"10.1016/j.orggeochem.2024.104919","url":null,"abstract":"<div><div>This study compares different lipid extraction methods and solvents with a focus on reducing or eliminating the use of dichloromethane (DCM). DCM has high neurotoxicity and is carcinogenic. This study focuses on lake sediment extraction using accelerated solvent extraction (ASE), sonication, QuEChERS, and Soxhlet methods and compares the solvents DCM, ethyl acetate (EtOAc), methanol (MeOH), and hexanes. For ASE and sonication extractions, the replacement of DCM with EtOAc results in similar extraction efficiencies for <em>n</em>-alkanes, <em>n</em>-alkanols, and slightly lower extraction of <em>n</em>-alkanoic acids. For example, when using an ASE with recovery standards, switching from 9:1 DCM/MeOH to 9:1 EtOAc/MeOH results in a small decrease of 10% in the extraction of total hydrocarbons (mostly <em>n</em>-alkanes), the same recovery of the alcohols (mostly <em>n</em>-alkanols), and a decrease of 19% for the acids (mostly <em>n</em>-alkanoic acids). The QuEChERS method reduces the volume of DCM, but had poor recovery compared to ASE or sonication. Many labs could switch from using DCM to EtOAc with ASE or sonication and have minor to no changes in extraction efficiency. The use of 9:1 hexanes/EtOAc produced high recoveries of <em>n</em>-alkanes and <em>n</em>-alkanols with a cleaner extract that requires less post extraction cleanup. Sonication has the potential advantage of higher throughput and lower costs, although hands-on time is higher than ASE and recoveries were not always as high as with ASE. While this study focuses on the extraction of lake sediment, the results should be transferable to the extraction of soils, rocks, and other biological materials with minor method adjustments.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"202 ","pages":"Article 104919"},"PeriodicalIF":2.6,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143386988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aromatic carotenoids and their aryl isoprenoid derivatives in the early Paleozoic rocks and crude oils of the Tarim Basin, China","authors":"Huiyuan Yang ,&nbsp;Jiaquan Zhou ,&nbsp;Jian Ma ,&nbsp;Xingqian Cui","doi":"10.1016/j.orggeochem.2025.104950","DOIUrl":"10.1016/j.orggeochem.2025.104950","url":null,"abstract":"<div><div>Emerging viewpoints suggest dynamic oceanic redox states and notable biotic turnovers in the early Paleozoic, but these aspects remain controversial and require further investigation. The Tarim Basin, which harbors significant marine hydrocarbon source rocks, records a typical phase of marine deposition of the early Paleozoic. In this study, we investigated biomarker compositions and patterns of selected rocks and crude oils of Early Cambrian to Late Ordovician ages from the Tarim Basin, China. Of particular importance are fossilized C₄₀ aromatic carotenoids and their biogenic aryl isoprenoid derivatives, which originate specifically from phototrophic sulfur bacteria inhabiting the euxinic photic zone and are indicative of redox conditions of ancient oceans. The prevalence of 2,3,6-aryl isoprenoids and isorenieratane indicates a biological origin of green sulfur bacteria, implying that the Tarim Basin witnessed euxinia in the subsurface photic zone during a certain period of the early Paleozoic. Along with other biomarker-based proxies, especially steroids and hopanoids, our results from the Tarim Basin suggest the dominance of reducing oceanic water column in the early Cambrian and the late evolution of partially oxygenated water column.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"202 ","pages":"Article 104950"},"PeriodicalIF":2.6,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 isotope characterization of hydrocarbon products from organic-sulfur-rich mudstones during closed hydrous-pyrolysis","authors":"Jaime Cesar ,&nbsp;Julito Reyes ,&nbsp;Omid H. Ardakani ,&nbsp;Levi J. Knapp","doi":"10.1016/j.orggeochem.2025.104963","DOIUrl":"10.1016/j.orggeochem.2025.104963","url":null,"abstract":"<div><div>A series of mudstones with varying organic sulfur content were subjected to hydrous pyrolysis and the produced oil and gas were analyzed. The samples come from the late Devonian Duvernay Formation (Canada), the late Miocene Onnagawa Formation (Japan), and the early Jurassic Gordondale Member of the Fernie Formation (Canada), in order of increasing organic sulfur content. Comparison of molecular parameters in the produced oils and residual extracts showed that these have almost identical values, with linear correlation near 1:1, except for polycyclic aromatics such as alkylphenanthrenes and alkyldibenzothiophenes. The excellent correlation suggests that in an ideal scenario, in the absence of long-distance migration, hydrocarbon mixing, and secondary alteration, produced oils and residual bitumen would have very similar molecular properties. In addition, for the same %VR_eqv, samples with higher sulfur content exhibit an apparent higher thermal maturity according to molecular ratios such as Pr/<em>n</em>C₁₈ and C₃₀Hopane/C₃₀Moretane. Generated gases showed source effects on their molecular and carbon isotope composition for the maturity interval analyzed herein (0.57 to 1.42 % VR_eqv). H₂S gas was generated only from the Gordondale samples and the isotope values are presented in this study.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"202 ","pages":"Article 104963"},"PeriodicalIF":2.6,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143438187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 constraints on the hydrocarbon generation and expulsion in source rocks with different primary organic matter compositions: A case study on the Lucaogou Formation in the Jimusaer Sag, Junggar Basin, Northwest China","authors":"Shiju Liu ,&nbsp;Gang Gao ,&nbsp;Xiangyun Shi ,&nbsp;Wenzhe Gang ,&nbsp;Baoli Xiang ,&nbsp;Ming Wang ,&nbsp;Wenzhi Zhao","doi":"10.1016/j.orggeochem.2025.104952","DOIUrl":"10.1016/j.orggeochem.2025.104952","url":null,"abstract":"<div><div>This study investigates the effects of different types of primary organic matters on hydrocarbon generation and expulsion of source rocks. Samples representing three typical source rocks from the Lucaogou Formation in the Jimusaer Sag were collected and analyzed by hydrous pyrolysis, total organic carbon, Rock-Eval, gas chromatography-mass spectrometry, organic petrology, and scanning electron microscopy. Distinct differences in crude oil biomarkers were observed between telalginite- and lamalginite-rich source rocks. Telalginite-rich source rocks exhibit higher abundances of pristane, phytane, <em>β</em>-carotane, gammacerane, and C₂₉ regular steranes, while lamalginite-rich source rocks are characterized by enrichments of C₂₄ tetracyclic terpane, C₂₉ hopane, and C₂₈ regular steranes. These biomarkers provide insights into the primary types of organic matter and their depositional environments with high water salinity of telalginite and low salinity of lamalginite. Hydrous pyrolysis results reveal that telalginite-rich source rocks demonstrate early hydrocarbon generation and a wider oil window than lamalginite-rich source rocks. Compared to lamalginite-rich source rocks, telalginite-rich source rocks produced better quality of crude oil, exhibit a smaller specific surface area of organic matter, and greater development of organic-inorganic pores, which contribute to their higher oil expulsion. These findings are helpful to the understanding of the constraints imposed by different primary organic matters on hydrocarbon generation and expulsion of the source rocks, and the insights have significant implications for exploration and development of the shale oil resources.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"202 ","pages":"Article 104952"},"PeriodicalIF":2.6,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing tetraether lipids as a paleotemperature proxy on western edge of the Chinese Loess Plateau: A cautionary tale","authors":"Jingjing Guo ,&nbsp;Louise Fuchs ,&nbsp;Martin Ziegler ,&nbsp;Youbin Sun ,&nbsp;Francien Peterse","doi":"10.1016/j.orggeochem.2025.104947","DOIUrl":"10.1016/j.orggeochem.2025.104947","url":null,"abstract":"<div><div>The 130,000-year long, high-resolution paleotemperature record obtained from branched glycerol dialkyl glycerol tetraethers (brGDGTs) stored in a loess-paleosol sequence from Yuanbao on the western Chinese Loess Plateau (CLP) does not follow global temperature variations, whereas these are recorded by traditional loess proxy records from the same section. Specifically, reconstructed temperatures are lowest during Marine Isotope Stage 5 (MIS5), even indicating colder interstadials than stadials, which contradict brGDGT-based records from other sections on the CLP. The overall low temperatures during wet periods may be explained by an increase in soil moisture availability, which dampens land surface temperatures by increasing the soil heat capacity. However, comparison of brGDGT distributions at Yuanbao with those in modern surface soils from the CLP and the global soil calibration dataset reveals a lack of modern analogues during the interval from ∼73 to 63 ka. Notably, the Isomer Ratio (IR) rapidly increases from 0.2 to 0.6 (corresponding to a pH shift of ∼2 units) during this period, indicating a drastic shift in the composition of the bacterial community that in turn may have influenced the MBT′_5Me-temperature relationship. This community shift occurs after Chinese Stadial-20 around 73 ka, a weak monsoon event tentatively linked to oceanic reorganizations after the Toba eruption, suggesting that this drastic change in (hydro)climate might have impacted brGDGT producers. We thus recommend thoroughly assessing brGDGT distributions and understanding the environmental background prior to interpretating brGDGT-based temperatures in a paleoclimatic context.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"201 ","pages":"Article 104947"},"PeriodicalIF":2.6,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Study on hydrocarbon retention and expulsion of kerogen based on centrifugal swelling method","authors":"Tian Liang ,&nbsp;Feng Zhu ,&nbsp;Zhao-Wen Zhan ,&nbsp;Xiao-Hui Lin ,&nbsp;Yan-Rong Zou ,&nbsp;Ping’an Peng","doi":"10.1016/j.orggeochem.2024.104921","DOIUrl":"10.1016/j.orggeochem.2024.104921","url":null,"abstract":"<div><div>Centrifugal swelling experiments using <em>n</em>-hexadecane and 1-methylnaphthalene were carried out to explore the connection between hydrocarbon retention and expulsion in type Ⅰ kerogen. A driving force-hydrocarbon expulsion model was innovatively established through the results of differential centrifugation experiments and low field nuclear magnetic resonance. Additionally, the hydrocarbon expulsion process of kerogen was categorized into three distinct stages based on the driving force, including free, intergranular state and immovable state (adsorption and swelling) hydrocarbon expulsion. A linear correlation also was established between the T₁/T₂ signal and the liquid hydrocarbon content during the swelling process, revealing that low-field NMR technology could effectively detect the retention of alkane compounds in kerogen. The study revealed that when the driving force is greater than 647.4 g N, most of the shale oil retained in the kerogen is in an immobile state, which cannot be exploited. Additionally, the hydrocarbon expulsion model based on the centrifugal experiment presents several advantages, including low equipment requirements, straightforward operation, and a broad range of applications. This model can effectively support various types of laboratories conducting shale oil retention assessment work, especially those in oilfields with relatively simple experimental setups.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"201 ","pages":"Article 104921"},"PeriodicalIF":2.6,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143373026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geochemistry Articles – November 2024","authors":"","doi":"10.1016/j.orggeochem.2025.104930","DOIUrl":"10.1016/j.orggeochem.2025.104930","url":null,"abstract":"","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"201 ","pages":"Article 104930"},"PeriodicalIF":2.6,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143419388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}