Organic Geochemistry最新文献

{"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":"2025-01-17","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}

{"title":"Geochemistry Articles – December 2024","authors":"","doi":"10.1016/j.orggeochem.2025.104931","DOIUrl":"10.1016/j.orggeochem.2025.104931","url":null,"abstract":"","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"201 ","pages":"Article 104931"},"PeriodicalIF":2.6,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143419389","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":"Application of biomarker and non-biomarker parameters to assess maturity using the Central Carpathian Paleogene Basin as a case study","authors":"Dorota Staneczek,&nbsp;Leszek Marynowski","doi":"10.1016/j.orggeochem.2025.104933","DOIUrl":"10.1016/j.orggeochem.2025.104933","url":null,"abstract":"<div><div>This study employs an integrated approach to investigate the thermal maturity of sedimentary rocks within the Central Carpathian Paleogene Basin (CCPB) by combining biomarker and non-biomarker parameters. The research primarily applies biomarker ratios based on the distribution of aliphatic and aromatic hydrocarbons and compares them with other paleotemperature indicators such as Rock-Eval pyrolysis. The results reveal a notable thermal gradient across the CCPB. The highest maturity levels are recorded in the Spiš Basin with calculated vitrinite reflectance values exceeding 2.0 %, and the least mature in the Orava Basin and Šariš Upland. The latter two contain unsaturated compounds, indicating immature organic matter. The variations in the paleotemperature pattern emerge from the changing thickness of overlying rocks in these areas. The findings suggest that the calculated vitrinite reflectance derived from the methylphenanthrene index (MPI1) is the most appropriate method for characterizing the broadest maturity range. When comparing the results of the illite/smectite-derived paleotemperatures with biomarker-derived ones, there is a good agreement in the results of the rocks with a higher degree of maturity. In contrast, at lower maturities, the illite/smectite-derived paleotemperatures appear to be overestimated. This study highlights the limitations of using a single maturity indicator and argues for a comprehensive approach combining different parameters to accurately reconstruct paleotemperatures. These results advance our understanding of the geological evolution of the CCPB and provide valuable information for future hydrocarbon exploration in the region. The CCPB is an excellent testing ground for comparing different maturity parameters.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"201 ","pages":"Article 104933"},"PeriodicalIF":2.6,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145152","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":"2025-01-16","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":"Discerning diagenetic pathways for discrete sterol precursors","authors":"Kelsey E. Doiron ,&nbsp;Peter K. Bijl ,&nbsp;Thomas Wagner ,&nbsp;Simon C. Brassell","doi":"10.1016/j.orggeochem.2025.104935","DOIUrl":"10.1016/j.orggeochem.2025.104935","url":null,"abstract":"<div><div>Studies of steroidal hydrocarbons in sedimentary sequences have helped elucidate the diagenetic fate of sterols, although discrete aspects of their transformation pathways remain unresolved. Steroidal hydrocarbons are prominent aliphatic hydrocarbons in Campanian to Paleocene sediments (∼78–63 Ma) recovered from the Transkei Basin (Hole U1581B), offshore South Africa, during IODP Expedition 392. Their distributions parallel those observed for other immature marine Cretaceous sediments, comprising C₂₇ to C₂₉ Δ⁴- and Δ⁵-sterenes and Δ^4,22- and Δ^5,22-steradienes, 20S and 20R diasterenes, partially rearranged sterenes (19-nor-5β-methylster-8-enes), and 5α- and 5β-steranes. In the upper Campanian through Danian sediment sequence, the proportion of C₂₈ steradienes (&gt;60%) far exceeds that for sterenes and steranes (∼10–30%) likely reflecting major phytoplankton contributions of their C₂₈ Δ^5,22 sterol precursor. The composition of steroidal hydrocarbons changes systematically with depth matching the succession of proven diagenetic transformations, including progressive increase in 20S/(20S + 20R) diasterenes. The occurrence of partially rearranged sterenes (19-nor-5β-methylster-8-enes) and increasing amounts of diasterenes in the middle Campanian are accompanied by a concomitant decrease in the proportions of sterenes and steradienes. Increasing downcore proportions (∼20%) of C₂₈ steranes and diasterenes indicates a pathway for diagenetic hydrogenation of Δ^4,22- and Δ^5,22-steradienes to Δ⁴- and Δ⁵-sterenes, which are subsequently rearranged to diasterenes or reduced to 5α- and 5β-steranes dependent on the agency of clay catalysis. Hence, contributions from steradienes lead to the diagenetic evolution of the carbon number distributions of steranes and diasterenes as they gradually become an aggregate measure of all sterol precursors.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"201 ","pages":"Article 104935"},"PeriodicalIF":2.6,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145070","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":"Revisiting the fingerprint of organic matters in speleothem by Electron Paramagnetic Resonance","authors":"Yves Perrette ,&nbsp;Hervé Vezin ,&nbsp;Bernard Fanget ,&nbsp;Julia Garagnon ,&nbsp;Jérome Poulenard","doi":"10.1016/j.orggeochem.2025.104929","DOIUrl":"10.1016/j.orggeochem.2025.104929","url":null,"abstract":"<div><div>The evolution of soil organic carbon (SOC) stocks is critical for both food production and climate change mitigation. This study uses advanced electron paramagnetic resonance (EPR) spectroscopy to investigate the spatial localisation and characterisation of organic carbon in speleothems, with a particular focus on methodological advances in recent decades. A speleothem sample from the Choranche cave in France was analysed using UV laser-induced fluorescence (LIF) and continuous wave EPR spectroscopy. The LIF analysis identified three main types of organic compounds − aromatic amino acids, aliphatic aromatics and larger aromatic compounds − distributed throughout the sample. EPR spectroscopy revealed the presence of Fe³⁺ and Mn²⁺ ions, along the entire sample for Fe³⁺ and more localised for Mn²⁺. When radical organic matter (ROM) is detected, first and second harmonic EPR imaging shows its collocation with Fe³⁺ and Mn²⁺, suggesting specific embedding conditions or source events. The study highlights a significant discrepancy between fluorescent organic matter (FOM) and ROM, challenging previous assumptions about their co-transfer from soil to speleothems. The results suggest that ROM is likely to be associated with specific soil redox conditions or high-energy events, whereas FOM represents a continuous background transfer. This distinction is crucial for accurate interpretations of soil organic carbon loss and its environmental implications. Future research should integrate detailed spectroscopic and isotopic analyses to better quantify organic carbon dynamics and their environmental proxies. Our results highlight the importance of distinguishing between different types of organic matter in speleothems to improve our understanding of soil organic carbon fluxes in relation to climate and human land use.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"201 ","pages":"Article 104929"},"PeriodicalIF":2.6,"publicationDate":"2025-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145154","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":"Geochemistry Articles – October 2024","authors":"","doi":"10.1016/j.orggeochem.2024.104896","DOIUrl":"10.1016/j.orggeochem.2024.104896","url":null,"abstract":"","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"199 ","pages":"Article 104896"},"PeriodicalIF":2.6,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143104868","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 – September 2024","authors":"","doi":"10.1016/j.orggeochem.2024.104885","DOIUrl":"10.1016/j.orggeochem.2024.104885","url":null,"abstract":"","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"199 ","pages":"Article 104885"},"PeriodicalIF":2.6,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143104869","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":"Spatial distribution of n-alkanes and GDGTs in the central Arctic Ocean during Marine Isotope Stages 1, 2 and 3","authors":"Akanksha Singh ,&nbsp;Sze Ling Ho ,&nbsp;Min-Te Chen ,&nbsp;Pei-Ling Wang ,&nbsp;Martin Jakobsson ,&nbsp;Richard Gyllencreutz ,&nbsp;Ludvig Löwemark","doi":"10.1016/j.orggeochem.2024.104920","DOIUrl":"10.1016/j.orggeochem.2024.104920","url":null,"abstract":"<div><div>Arctic sea ice affects Earth’s albedo, marine productivity and organic matter (OM) transport. Lipid biomarkers have been used to trace OM transport in the Arctic Ocean, but uncertainties remain regarding their spatio-temporal variations and sources over the last glacial cycle. Our study addresses these gaps by analyzing glycerol dialkyl glycerol tetraethers (GDGTs), <em>n</em>-alkanes, and total organic carbon (TOC) in nine central Arctic sediment cores spanning the Marine Isotope Stages (MISs) 3–1. Elevated IIIa/IIa values of branched GDGTs (brGDGTs) in the central Arctic throughout the studied interval suggest a marine origin, contrasting to the #rings_tetra ratios which indicate a terrigenous brGDGT source. We propose that the IIIa/IIa ratio may be a more sensitive indicator of in situ brGDGT production in the central Arctic marine sediments. TOC and biomarker concentrations in the Central Lomonosov Ridge (CLR) cores were higher compared to those from the Lomonosov Ridge off Greenland (LRG) and Morris Jesup Rise (MJR) cores. Low productivity in the central Arctic, along with similarity in the spatial patterns of marine-derived brGDGTs and isoprenoid GDGTs, as well as terrestrial long-chain <em>n</em>-alkanes, suggests that these biomarkers are primarily transported to the central Arctic from the Siberian shelves. This spatial pattern persisted throughout MISs 3–1, suggesting continued sea ice drift during glacial periods, albeit with weakened intensities. Meanwhile, the spatiotemporal variations of the Branched Isoprenoid Tetraether (BIT) index in the region plausibly reflect the relative changes in the crenarchaeol and brGDGT production on the shelf and/or selective degradation of crenarchaeol during its transport.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"201 ","pages":"Article 104920"},"PeriodicalIF":2.6,"publicationDate":"2024-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143378488","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":"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":"2024-12-18","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}