Organic Geochemistry最新文献

{"title":"Mid- to Late-Holocene branched GDGT-based air temperatures from a crater lake in Cameroon (Central Africa)","authors":"Guillemette Ménot ,&nbsp;Salomé Ansanay-Alex ,&nbsp;Valérie F. Schwab ,&nbsp;Gilbert Todou ,&nbsp;Olivier Séné ,&nbsp;Jean-Michel Onana ,&nbsp;Gerd Gleixner ,&nbsp;Dirk Sachse ,&nbsp;Yannick Garcin","doi":"10.1016/j.orggeochem.2025.104982","DOIUrl":"10.1016/j.orggeochem.2025.104982","url":null,"abstract":"<div><div>African low-latitude regions tend to be underrepresented in global continental temperature reconstructions, limiting both our understanding and the reliability of predictions of past and future changes in temperature and precipitation in those parts of the world. The lack of continuous sedimentary archives and quantitative temperature proxies further complicates this issue, especially outside Eastern Africa. Here, we use data collected in Cameroon lakes to assess branched glycerol dialkyl glycerol tetraether (brGDGT)-based temperature proxies and examine potential confounding variables impacting temperature reconstructions. By analyzing GDGT distributions in soil watershed, water column, and surface sediment samples from a total of 11 Cameroon lakes, we could verify that the degree of methylation of brGDGTs (through the MBT′_5Me) can serve as a reliable indicator for reconstructing mean annual air temperatures. Additionally, we could confirm that surface water conductivity represents a controlling factor for the brGDGT assemblage in surface sediments of crater lakes. Moreover, we provide the first reconstruction of Mid- to Late-Holocene GDGT-based air temperatures for a crater lake in Cameroon (Central Africa), revealing a temperature decrease of 2.5 °C over the last 7000 years, which agrees with recently published records for East Africa but exceeds current model predictions. These discrepancies highlight the need for additional studies to focus on this geographically underrepresented area.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"204 ","pages":"Article 104982"},"PeriodicalIF":2.6,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760936","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":"Reforestation in northeastern China increased the soil microbial necromass carbon accumulation by influencing glomalin and enzyme activities","authors":"Li Pan ,&nbsp;Xiuwei Wang","doi":"10.1016/j.orggeochem.2025.104983","DOIUrl":"10.1016/j.orggeochem.2025.104983","url":null,"abstract":"<div><div>Farmland reforestation is a common measure aimed at improving soil properties and preventing soil carbon loss, with microbial necromass carbon (MNC) being a crucial component of soil organic carbon. The changes in soil MNC content are closely linked to microbial community structure and microbial metabolites. However, the precise impact of microbial community, enzyme activities, and glomalin-related soil protein (GRSP) on MNC accumulation following the conversion from farmland to forest remains incompletely understood. To address these knowledge gaps, soil samples were collected from a farmland and two adjacent forests in the black soil region of Northeast China, focusing on the 0–30 cm depth. By utilizing the microbial cell wall’s biomarker amino sugars, the study estimated MNC contents and investigated how reforestation influences MNC levels in farmland, along with exploring the underlying mechanisms. The results revealed a significant increase in soil MNC by 139–167% and soil organic carbon by 25–34% post-reforestation. Moreover, the contribution of MNC to the soil organic carbon pool was enhanced following reforestation. It was observed that GRSP content was predominantly influenced by microbial community composition, with β-1,4-N-acetyl-glucosaminidase and GRSP emerging as key indicators affecting soil MNC levels. Notably, compared to microbial community composition alone, GRSP and enzyme activities exerted a more substantial impact on MNC in soil. In conclusion, this study underscores the significance of GRSP and enzyme activities in shaping soil MNC accumulation, thereby enhancing our understanding of the implications of reforestation on soil carbon stocks and the microbial-driven mechanisms at play.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"204 ","pages":"Article 104983"},"PeriodicalIF":2.6,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143687784","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":"Sedimentary geochemical records of the palaeovegetation and palaeoclimate evolution in the Pinghu Formation, Western Slope Belt, Xihu Sag, East China Sea Basin","authors":"Yanan Wang ,&nbsp;Lin Wei ,&nbsp;Xiong Cheng ,&nbsp;Hui Diao ,&nbsp;Wenjun Li ,&nbsp;Dujie Hou ,&nbsp;Jiansheng Li","doi":"10.1016/j.orggeochem.2025.104973","DOIUrl":"10.1016/j.orggeochem.2025.104973","url":null,"abstract":"<div><div>The sedimentary development of source rocks in marine-continental transitional facies is controlled mainly by the synergistic evolution of palaeovegetation and palaeoclimate. A set of marine-continental transitional coal seams in Xihu Sag of the East China Sea Basin were discovered at the end of the last century, whose lithology is mainly fine-grained sedimentary, with significant non-homogeneity and complex developmental control factors. Although systematic geochemical evaluations and hydrocarbon potential studies have been carried out on the source rocks in the Xihu Sag, few studies have focused on the fine-grained characterization of the palaeovegetation and palaeoclimate evolution during the depositional period. In this study, the palaeovegetation and palaeoclimate of the Pinghu Formation in Xihu Sag have been reconstructed based on biomarkers, pollen abundance, and trace elements. The organic matter of the Pinghu Formation is mainly input from terrigenous higher plants. The biomarkers reveal that gymnosperms gradually increase from the early to late stages of the Pinghu Formation, whereas pteridophytes exhibit the opposite trend. The contribution of gymnosperms to organic matter in the Wuyunting area is higher than in the Pinghu area. Furthermore, the number of temperate deciduous broad-leaved angiosperms (<em>Alnipollenites</em>, <em>Ulmipollenites</em>, <em>Momipites</em>, and <em>Juglanspollenites</em>) and mountain coniferous gymnosperms (<em>Pinuspollenites</em>) increased from the early to late stages of the Pinghu Formation, while the abundance of tropical/subtropical plants (<em>Quercoidites</em>, <em>Taxodiaceaepollenites</em>, and <em>Salixipollenites</em>) decreased. The vegetation succession<!--> <!-->is characterized by gradually transforming from tall gymnosperms to low-growing pteridophytes from the northern Wuyunting area to the southern Pinghu area. In conclusion, palynological data (including pteridophytes, angiosperms, and gymnosperms) and trace element ratios indicate that from the early to late stages of the Pinghu Formation, the palaeoclimate gradually became colder, with humidity and water depth decreasing.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"203 ","pages":"Article 104973"},"PeriodicalIF":2.6,"publicationDate":"2025-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143578858","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":"Preservation of archaeal core lipids in siliceous hot spring deposits: An experimental study","authors":"L. Weimann ,&nbsp;M. Reinhardt ,&nbsp;C. Ostertag-Henning ,&nbsp;J.-P. Duda ,&nbsp;V. Thiel","doi":"10.1016/j.orggeochem.2025.104974","DOIUrl":"10.1016/j.orggeochem.2025.104974","url":null,"abstract":"<div><div>Siliceous hot spring systems have been present on our planet since at least 3.5 Ga, often hosting diverse communities of Archaea. Isoprenoid core lipids are important biomarkers for these microorganisms, but these lipids have only been reported from modern and subrecent siliceous sinter settings, perhaps indicating a bias against their long-term preservation in such environments. We conducted closed-system maturation experiments with the archaeal core lipids archaeol and isoprenoid glycerol dialkyl glycerol tetraethers (isoGDGTs) at 250 °C and 300 bar for 14 days. Compounds were heated with artificial sea water, with and without silica, as single compounds, and as part of a lipid mixture from a microbial mat. The products were analyzed using gas chromatography-mass spectrometry, scanning electron microscopy, and X-ray diffraction. This allowed to assess the preservation potential of these biomarkers during simulated siliceous sinter formation and subsequent diagenesis. Amorphous silica gel transformed into small microspheres (∼10 µm) when heated with single organic compounds, but formed more irregularly shaped rounded grains when heated with the lipid mixture. The presence of silica led to an enhanced degradation of archaeol, most likely caused by hydroxyl radicals deriving from silica-fluid interactions. IsoGDGTs, in contrast, were less affected by silica and showed an enhanced stability when heated as part of the lipid mixture. The results indicate that (i) the silica matrix, (ii) the molecular structure, and (iii) the presence of other organic compounds play a critical role for the preservation of archaeal core lipids in siliceous hot spring systems.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"204 ","pages":"Article 104974"},"PeriodicalIF":2.6,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143631873","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":"Optimized sample cleanup for compound-specific isotope analysis of polycyclic aromatic hydrocarbons in complex environmental samples","authors":"Md Samrat Alam ,&nbsp;Jason M.E. Ahad ,&nbsp;Colin A. Cooke","doi":"10.1016/j.orggeochem.2025.104966","DOIUrl":"10.1016/j.orggeochem.2025.104966","url":null,"abstract":"<div><div>Compound-specific isotope analysis (CSIA) using gas chromatography – isotope ratio mass spectrometry is a powerful tool to discriminate sources of polycyclic aromatic hydrocarbons (PAHs). However, interferences from co-eluting peaks often prevent accurate isotopic measurements in complex environmental samples. Purification of sample extracts is thus a crucial analytical step. In this study, we report a rapid and effective cleanup method using high-performance liquid chromatography (HPLC) that provides high integrity isolation of PAHs suitable for CSIA. The method reported here was effective at purifying both parent and alkylated PAHs from several highly complex matrices, including river sediments, bitumen, petroleum coke, and wildfire ash. HPLC separation removed much of the interfering aromatic unresolved complex mixture (UCM) and significantly improved chromatography, yielding well-resolved PAH peaks with high intensities and signal-to-noise ratios. Recoveries and purities of target compounds following HPLC separation were 70 ± 13% and 97 ± 5%, respectively. No noticeable differences (± 0.5‰) were observed in the carbon isotope values (δ¹³C) of standards subjected to extraction and HPLC purification steps, indicating negligible isotopic fractionation associated with the protocol. The δ¹³C values for individual PAHs in samples were comparable to those previously reported for the same sample types, further demonstrating this method’s high level of accuracy and precision. Additionally, this technique allows for isotopic characterisation of a larger number of 4- to 5-ring PAHs compared to many previous studies due to removal of much of the later-eluting UCM, potentially providing greater insight into source discrimination and understanding of PAH deposition and transformation processes. While the focus of this investigation was on PAHs, this technique could be adapted to other problematic compounds targeted for CSIA.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"203 ","pages":"Article 104966"},"PeriodicalIF":2.6,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511397","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":"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":"2025-02-26","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":"Sources of bacterial 3-hydroxy fatty acids in Liangzihu Lake from central China: Implications for paleoclimate reconstruction","authors":"Honghai Wang ,&nbsp;Yi Yang ,&nbsp;Canfa Wang ,&nbsp;Shucheng Xie","doi":"10.1016/j.orggeochem.2025.104949","DOIUrl":"10.1016/j.orggeochem.2025.104949","url":null,"abstract":"<div><div>Bacterial 3-hydroxy fatty acids (3-OH-FAs) derived proxies are new tools for paleoclimate reconstruction. However, their effectiveness in temperature reconstruction in lake environments remains unclear. We investigated the compositions of 3-OH-FA and bacterial community across a transect from nearshore soils to water column and surface sediments in the center of Liangzihu Lake (LZH), central China, to elucidate the origins of 3-OH-FA within the lake environments and to evaluate their potential as temperature proxies. The 3-OH-FA in lake center sediments was found to be produced in situ, which can be further supported by the 16S rRNA gene sequencing results. We quantified the input of soil organic matter (OM) in the lake using a δ¹³C_org based two-end member model. The contribution of soil OM ranged from above 50% in nearshore sediments to &lt; 20% in the lake center, reflecting a decreased influence of soil contribution offshore. Moreover, 3-OH-FA based temperature proxies, RAN₁₃ (the ratio of <em>anteiso</em> to <em>normal</em> C₁₃) and RIN₁₇ (the ratio of <em>iso</em> to <em>normal</em> C₁₇) were examined. The temperature estimates derived from the RAN₁₃ were close to the meteorological temperature, whereas the temperature estimates based on RIN₁₇ are lower than the measured temperature. Therefore, our study not only elucidates the sources of 3-OH-FAs within LZH but also evaluates the reliability of associated temperature indices, which provides insights into temperature reconstruction in lake sediment cores.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"203 ","pages":"Article 104949"},"PeriodicalIF":2.6,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143474541","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":"Structural properties of organic matter in marine-continental transitional shales and impacts on methane accumulation","authors":"Zhen Qiu ,&nbsp;Dongjun Song ,&nbsp;Jingyu Zhang ,&nbsp;Qin Zhang ,&nbsp;Wen Liu ,&nbsp;Weiliang Kong ,&nbsp;Guangyin Cai ,&nbsp;Wanli Gao ,&nbsp;Tianquan Qu","doi":"10.1016/j.orggeochem.2025.104946","DOIUrl":"10.1016/j.orggeochem.2025.104946","url":null,"abstract":"<div><div>The chemical structure characteristics of organic matter (OM) in marine-continental transitional (MCT) shales and the controls on shale gas accumulation were revealed through analysis of Raman spectroscopy, infrared spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and CO₂ adsorption tests on the Lower Permian Shan-2 shale OM samples from the eastern margin of the Ordos Basin. Organic matter in the high-mature shale is enriched in aromatic groups, with a noticeable condensation and polymerization of the chemical structure after ∼3.0 %R_mc (Raman-based R_o). As %R_mc increases from 2.30 to 3.42, the position of the (002) peak from the stacking of aromatic layers increases from 25.15° to 25.88° in XRD spectra, the spacing between aromatic layers (d₀₀₂) decreases from 0.3540 nm to 0.3444 nm, the calculated graphitization degree (level of OM transforming into graphite) gradually increases, and the carbon layers in the OM evolve from a chaotic shape to a better-oriented state in TEM images, directly indicating an elevated graphitized level. Release of heteroatoms from OM results in reduced average lateral size (L_a) and stacking height (L_c) of the aromatic layer, reaching minimum values at ∼3.0 to 3.2 %R_mc. The stacking of aromatic layers forms some organic micropores, as evidenced by similar micropore size distribution between OM and bulk shale samples, possibly favoring methane accumulation. These findings provide new insights into the factors that affect the gas accumulation characteristics in MCT shales.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"203 ","pages":"Article 104946"},"PeriodicalIF":2.6,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143464518","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":"Chemodiversity of soil dissolved organic matter complementally improved by stepwise elution and electrospray ionization modes","authors":"Shasha Zhuo,&nbsp;Rong Qin,&nbsp;Qing-Long Fu","doi":"10.1016/j.orggeochem.2025.104965","DOIUrl":"10.1016/j.orggeochem.2025.104965","url":null,"abstract":"<div><div>The chemodiversity of dissolved organic matter (DOM) molecules can affect the biogeochemical cycling of carbon and nitrogen in terrestrial and aquatic environments. In this study, the negative and positive ion modes of electrospray ionization (ESI(−) and ESI(+), respectively) coupled with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) were employed to reveal the chemical composition of seven soil DOM isolates by stepwise elution using different methanol/water solvents. The intensity percentage of CHON molecules in soil DOM detected in the ESI(+) mode was 4.6%–47.3% higher than that for the ESI(−) mode. The O/C ratio, H/C ratio, and the nominal oxidation states of the carbon value of soil DOM molecules linearly correlated (<em>R</em>² &gt; 0.8 for 72% number of stepwise eluted DOM isolates) with the increasing volume of methanol in the SPE elution solvents in dual ion modes, demonstrating the selective fractionation of oxygen-rich and highly polar molecules by methanol-poor solvents. This polarity-dependent fractionation is expected to be universal across different soils. These results suggest that combining the ESI(−) and ESI(+) modes with stepwise elution enables the comprehensive characterization of soil DOM composition, favouring the in-depth understanding of the critical roles of DOM in the biogeochemical cycles of carbon and nitrogen.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"203 ","pages":"Article 104965"},"PeriodicalIF":2.6,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552904","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":"2025-02-22","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}