Organic Geochemistry最新文献

{"title":"Organic matter accumulation driven by land-sea interactions during the Late Cretaceous: A geochemical study of the Nenjiang Formation, Songliao Basin","authors":"Congsheng Bian ,&nbsp;Shiju Liu ,&nbsp;Wei Liu ,&nbsp;Xiong Cheng ,&nbsp;Xin Liu ,&nbsp;Jin Dong ,&nbsp;Rui Wang ,&nbsp;Yongxin Li ,&nbsp;Ming Guan ,&nbsp;Qianhui Tian ,&nbsp;Wenzhi Zhao","doi":"10.1016/j.orggeochem.2024.104901","DOIUrl":"10.1016/j.orggeochem.2024.104901","url":null,"abstract":"<div><div>The Late Cretaceous Nenjiang Formation in the Songliao Basin presents a unique setting to examine how climate change and sea-level rise influenced organic matter accumulation. This study combines TOC analysis, Rock-Eval pyrolysis, GC–MS, GC–MS-MS, and elemental geochemistry on core samples from two wells to assess organic matter deposition before and after transgressive events. TOC values range from 0.18 to 14.63 wt%, with significant variations in hydrocarbon potential and thermal maturity. Periodic warm and cool climates triggered intermittent seawater intrusions that created anoxic conditions conducive to marine diatom and lacustrine dinoflagellate proliferation. Extended warm periods, however, suppressed dinoflagellate development and reduced paleo-productivity. The activity of methanogenic bacteria further contributed to the degradation of sedimentary organic matter, hindering its accumulation. While warm climates facilitated flood events that transported terrigenous nutrients, enhancing dinoflagellate blooms and expanding the oxygen minimum zone. These findings highlight the bio-environmental interactions that governed organic matter accumulation during transgressions, offering insights for exploration in similar sedimentary environments.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"199 ","pages":"Article 104901"},"PeriodicalIF":2.6,"publicationDate":"2024-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746085","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":"C/H isotope fractionation of hydrocarbon gases from hydrogenation of organic matter: Insights from hydrothermal experiments","authors":"Kun He ,&nbsp;Xiaomei Wang ,&nbsp;Chunlong Yang ,&nbsp;Linfeng Xie ,&nbsp;Shuichang Zhang","doi":"10.1016/j.orggeochem.2024.104884","DOIUrl":"10.1016/j.orggeochem.2024.104884","url":null,"abstract":"<div><div>It is widely accepted that organic–inorganic interactions involving hydrogen-rich fluids (H₂O and H₂) play a significant role in hydrocarbon (HC) generation in sedimentary basins, and the effects of hydrogenation of organic matter (OM) by H₂O/H₂ on C/H isotope fractionation remain poorly understood. This study investigates these effects through a series of pyrolysis experiments conducted at 330–420 °C and 50 MPa, encompassing three groups: (1) anhydrous pyrolysis with kerogen only (Group 1), (2) kerogen and H₂O (Group 2), and (3) kerogen, H₂O, and Fe_1-<em>_x</em>S (Group 3). Groups 2 and 3 were designed to simulate hydrogenation of OM by H₂O and H₂, respectively. Results show that HC gas yields in Group 3 experiments are 1.8 to 3.2 times of those in Group 1, while yields in Group 2 are lower than Group 1. Moreover, hydrogenation by H₂ produces HC gases with smaller ¹³C fractionation and more negative δ²H values compared to hydrogenation by H₂O. These findings suggest distinct mechanisms for HC gas generation during H₂-OM and H₂O-OM reactions. Further analysis demonstrates that the equilibrium isotope effect (EIE) governs ¹³C and ²H isotope fractionation during hydrogenation of OM by H₂. Importantly, the EIE for ²H isotope fractionation of H₂O-H₂, CH₄-H₂, and OM-H₂ is evaluated under both experimental and geological conditions. This study provides crucial insights into the significant influence of hydrogenation of OM by H₂ on the generation and C/H isotopic fractionation of HC gases, as well as the evolution and preservation of H₂ in organic-rich shales.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"199 ","pages":"Article 104884"},"PeriodicalIF":2.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699708","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":"Characteristics of carbazole compounds in ultra-deep marine oil from Fuman oilfield, Tarim Basin: Significance for thermal maturity assessment of crude oil","authors":"Zhongdeng Lu ,&nbsp;Hongwei Ping ,&nbsp;Honghan Chen ,&nbsp;Zulin Chen ,&nbsp;Yanqiu Zhang ,&nbsp;Zhou Xie ,&nbsp;Yintao Zhang ,&nbsp;Xu Chen","doi":"10.1016/j.orggeochem.2024.104895","DOIUrl":"10.1016/j.orggeochem.2024.104895","url":null,"abstract":"<div><div>Carbazoles in Ordovician ultra-deep marine oil from the F_I17 fault zone in Fuman oilfield (Tarim Basin) were separated using a recently proposed silica gel column chromatographic method and the enriched fractions were analyzed by GC–MS. Biomarker and carbon isotope signatures revealed that all oil in the study area was produced from the same source rock and that compositional differences can be attributed to thermal maturation. The convergent ratios of N-H shielded isomers/N-H half shielded isomers and benzo[<em>a</em>]carbazole/(benzo[<em>a</em>]carbazole + benzo[<em>c</em>]carbazole) suggested that carbazoles in crude oil had not been affected by vertical migration. Therefore, thermal maturity was identified as the main controlling factor affecting chages of carbazole concentrations and ratios in crude oil. The concentrations of the total carbazole and its three isomers (N-H shielded isomers, N-H half shielded isomers and exposed isomers) in crude oil decreased sharply with increasing maturity. The 1,8-dimethylcarbazole/carbazole (1,8-MCa/Ca) and 1,8-dimethylcarbazole/2,4-dimethylcarbazole (1,8-MCa/2,4-MCa) ratios showed significant correlation with maturity expressed as %<em>VRE</em> (the vitrinite reflectance equivalent converted from MPI₁ and MPR) when %<em>VRE</em> is &lt;1.2 %. Similar trends were observed in the 1-methylcarbazole/3-methylcarbazole (1-MCa/3-MCa) as well as 1,8-dimethylcarbazole/2,6- dimethylcarbazole (1,8-DMCa/2,6-DMCa), (1,5- dimethylcarbazole + 3-ethylcarbazole)/2, 6-dimethylcarbazole ((1, 5-DMCa + 3-ECa)/2, 6-DMCa), and (1, 4-dimethylcarbazole + 4-ethylcarbazole)/2, 6-dimethylcarbazole ((1, 4-DMCa + 4-ECa)/2, 6-DMCa) when the %<em>VRE</em> of crude oil exceeds 1.0 %. This indicated that the concentrations and ratios of carbazole can be used to qualitatively evaluate crude oil maturity. The ratio of 1,8-dimethylcarbazole/1-ethylcarbazole (1,8-DMCa/1-ECa) showed a strict linear relationship with %<em>VRE</em>. The maturity of marine oil can be calculated using the formulas <em>%R</em>c (the vitrinite reflectance equivalent calculated from MPI₁) = −0.0335(1, 8-DMCa/1-ECa) + 1.2902 or <em>%R</em>c₁ (the vitrinite reflectance equivalent calculated from MPR) = −0.0405 (1, 8-DMCa/1-ECa) + 1.3418. The study can be helpful for exploring ultra-deep hydrocarbons and restoring the thermal history of source rocks in the Tarim Basin.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"198 ","pages":"Article 104895"},"PeriodicalIF":2.6,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652441","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":"Hydrogen isotope fractionation during aromatization to form alkylnaphthalene: Insights from pyrolysis experiments of 1-n-butyldecalin","authors":"Bin Cheng ,&nbsp;Zhiwei Wei ,&nbsp;Yiman Zhang ,&nbsp;Hanyu Deng ,&nbsp;Yuxian Li ,&nbsp;Haozhe Wang ,&nbsp;Zewen Liao","doi":"10.1016/j.orggeochem.2024.104881","DOIUrl":"10.1016/j.orggeochem.2024.104881","url":null,"abstract":"<div><div>Alkylnaphthalene homologues are important components of aromatic fraction in sedimentary organic matter and contain significantly geochemical information relative to formation and evolution of the host organic matter. They mainly originate from hydrocarbon aromatization reaction which involves the dehydrogenation of aliphatic rings resulting in the fractionation of stable hydrogen isotopes between aromatic hydrocarbons and their precursors. To examine these processes, this study thermally pyrolysed 1-<em>n</em>-butyldecalin (BD) at different time intervals under 360 °C/50 MPa to study the aromatization and hydrogen isotope fractionation during alkylnaphthalene formation and evolution. The relative content of aromatic products, such as naphthalene (N) and 1-methylnaphthalene (1-MN), increases with increasing aromatization. Sulfur enhanced the degree of aromatization during BD thermal evolution, resulting in greater N and 1-MN formation. For the compounds with the same carbon skeleton, i.e. <em>tran</em>-1-methyldecalin (1-MD), 5-methyltetraline (5-MT) and 1-MN, the ²H enrichment follows the order δ²H_1-MD &lt; δ²H_5-MT &lt; δ²H_1-MN during the low thermal conversion of BD. However, the order was subsequently destroyed with increasing aromatization. The results indicate that hydrocarbon aromatization can enrich aromatic hydrocarbon in ²H, resulting in a higher δ²H value of higher aromatic-ring-number hydrocarbon than that of a lower aromatic-ring-number at low aromatization. However, ²H enrichment will decrease and even result in a reverse order with enhanced aromatization. Our findings are beneficial for understanding genetic mechanism and hydrogen isotope fractionation effect during the formation and evolution of aromatic hydrocarbons.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"198 ","pages":"Article 104881"},"PeriodicalIF":2.6,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652442","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":"Porphyrin protonation induces decoupling of trace metals in petroleum","authors":"Jingkun Zhang ,&nbsp;Jian Cao ,&nbsp;Wenjun He","doi":"10.1016/j.orggeochem.2024.104878","DOIUrl":"10.1016/j.orggeochem.2024.104878","url":null,"abstract":"<div><div>The mechanism of migration of trace metals in petroleum systems is poorly understood, which limits our understanding of organic–inorganic interactions and their application in tracing oil sources. Based on a molecular model of metalloporphyrin, numerical simulations involving density functional theory have revealed that porphyrin protonation is associated with trace-metal decoupling in petroleum. Trace metals readily form covalent bonds with weakly protonated porphyrin N to form stable compounds. However, the metals may be decoupled at lower fluid pH owing to increased N protonation, which activates the formation of ionic bonds with O²⁻. The released metals may then be fixed in authigenic calcite cement (ACC) reservoirs through substitution of Ca. For Mg, Mn, and Fe, the decoupling order is Mg &gt; Fe &gt; Mn, whereas that for the substitution of Ca is Mn &gt; Fe &gt; Mg, reflecting the complexity of organic–inorganic interactions and indicating the potential application of metals in fingerprinting oil sources. This case study of the southern Junggar Basin, China, revealed that Mn, Fe, and Mg enrichment of ACC may provide indications of Paleozoic, Mesozoic, and Cenozoic petroleum systems, respectively, providing a potential new approach for the tracing of oil sources in petroleum basins.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"198 ","pages":"Article 104878"},"PeriodicalIF":2.6,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652438","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":"Influencing factors of hydrogen isotopic fractionation of light hydrocarbons during evaporation and implications","authors":"Wenna Liu ,&nbsp;Wanglu Jia ,&nbsp;Qiang Wang ,&nbsp;Jian Chen ,&nbsp;Jinbu Li ,&nbsp;Ping’an Peng","doi":"10.1016/j.orggeochem.2024.104894","DOIUrl":"10.1016/j.orggeochem.2024.104894","url":null,"abstract":"<div><div>The isotopic fractionation of organic compounds during evaporation is one of the most critical issues in the field of stable isotopes. The hydrogen (H) isotopic compositions of light hydrocarbons (LHs) in oil have gained increasing interest in the research of oil genesis in recent years. However, compared to carbon (C) isotopes, our understanding of H isotopic fractionation patterns and influences for various types of LHs during evaporation is limited. In this study, we performed evaporation experiments at a constant temperature on LHs in three systems: single compound, alkane mixture, and light oil. We assessed the contents and H isotopic compositions of individual LHs in the residual liquid phase. The degree of H isotopic fractionation and influencing factors are studied combined with C isotopes. The H isotopic fractionation of LHs exhibits “inverse isotope fractionation” characteristics (a depletion in D in the residual LHs) with progressive evaporation, which is opposite to the C isotopic fractionation. The degree of isotopic fractionation is influenced by the evaporation system, the compounds’ molecular weight, and their structure. (1) The isotopic fractionation degree of H and C decreases in the following order: light oil &gt; alkane mixture &gt; single compound system. This difference may be related to the unsaturation level of the evaporative system and the evaporation matrix. (2) For LHs with the similar structure in the same evaporation system, the degree of H isotopic fractionation increases with increasing molecular weight due to the buffering effect of the sample pool, while the magnitude of C isotopic fractionation decreases. (3) For LHs with the same C number, methylcyclohexane (MCH) has a lower evaporation rate and less isotopic fractionation than the other C₇ compounds like 3-methylhexane (3-MH), <em>n</em>-heptane (<em>n</em>C₇), and toluene (Tol).</div><div>The distinctive fractionation characteristics of H isotopes make them very useful in geological applications. Combining H and C isotopic compositions of the same compound with the commonly used molecular ratios of LHs (e.g., <em>n</em>C₇/MCH, Tol/<em>n</em>C₇) enables full differentiation of three critical processes controlling oil formation: evaporation, thermal maturation, and biodegradation. Furthermore, the differences in H isotopic compositions between C₇ LHs (3-MH, <em>n</em>C₇, and Tol) may be changed by evaporation, but the variation range is much smaller than that caused by source differences. Therefore, combining H and C isotopes may have great potential for oil source characterizations.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"198 ","pages":"Article 104894"},"PeriodicalIF":2.6,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572988","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":"Characterisation of dissolved organic matter in two contrasting arsenic-prone sites in Kandal Province, Cambodia","authors":"Oliver C. Moore ,&nbsp;Amy D. Holt ,&nbsp;Laura A. Richards ,&nbsp;Amy M. McKenna ,&nbsp;Robert G.M. Spencer ,&nbsp;Dan J. Lapworth ,&nbsp;David A. Polya ,&nbsp;Jonathan R. Lloyd ,&nbsp;Bart E. van Dongen","doi":"10.1016/j.orggeochem.2024.104886","DOIUrl":"10.1016/j.orggeochem.2024.104886","url":null,"abstract":"<div><div>Aquifers throughout Asia are impacted by the release of geogenic arsenic (As) into groundwater by microbial reduction of As-bearing Fe(III) (oxy)hydroxide minerals, severely impacting water quality. Groundwater dissolved organic matter (DOM) is likely key to As release, mainly as electron donor or electron shuttles. This study used optical analyses and ultra-high resolution mass spectrometry to examine the sources and composition of groundwater DOM in the As-prone aquifers of Kandal Province, Cambodia, at boreholes with differing host lithology (clay- and sand-dominated). Groundwater and surface water DOM composition were related to As concentrations, to infer the potential role of DOM in promoting As release. Optical and molecular-level analyses indicated an overall dominance of terrestrial-derived DOM in the groundwater samples, with higher freshness index and relative abundance (RA) of aliphatic compounds in clay compared to sand-dominated lithology. Compared to surface water, groundwater DOM had relatively lower O/C ratios and nominal oxidation state of carbon (−0.19 to −0.13 compared to 0.04 for ground and surface water, respectively), with a lower %RA of aliphatic compounds and higher %RA of carboxyl-rich alicyclic molecules, suggesting microbial processing of DOM since percolation into the aquifer. Concentrations of As across both sites were negatively correlated with DOM tryptophan:fulvic-like fluorescence and the %RA of aliphatics, potentially indicating microbial degradation of biolabile DOM in connection with As release, which is consistent with its role as an electron donor source. Together these data support DOM composition as an important control on microbial mediated As release.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"198 ","pages":"Article 104886"},"PeriodicalIF":2.6,"publicationDate":"2024-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652445","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":"Origin and preservation mechanisms of organic matter in carbonate concretions from Lower Cambrian black shales in South China","authors":"Xinyan Fang ,&nbsp;Qing Zhang ,&nbsp;Liangliang Wu ,&nbsp;Ansong Geng ,&nbsp;Shufen Liu ,&nbsp;Pufan Wang ,&nbsp;Xiao Liang","doi":"10.1016/j.orggeochem.2024.104876","DOIUrl":"10.1016/j.orggeochem.2024.104876","url":null,"abstract":"<div><div>Carbonate concretions are widely used in paleoclimate, paleoenvironmental, and paleontological studies, and even in the study of potential life on Mars. These petrological, elemental, isotopic, and lipid biomarker signals in Meso-Cenozoic carbonate concretions (relatively low thermal maturity) can effectively preserve details of seawater conditions and benthic ecosystems during the deposition of their host sediments/rocks. However, such research on Precambrian-Cambrian carbonate concretions under highly mature conditions remains scarce, and the ability of these ancient carbonate concretions to retain their original biogenic information remains uncertain. To achieve that, this study examines two Cambrian carbonate concretions, using samples from the center, transition, and rim of each, and their adjacent host black shales from the Lower Cambrian Qiongzhusi Formation in the Yangtze Block, South China. Organic and inorganic geochemical analyses were combined to elucidate the origin and preservation process of organic matter (OM) in these ancient Cambrian carbonate concretions. The results show that the thermal maturity of OM within these concretions (1.8 % EqV<em>R</em>_o) is relatively low compared to their adjacent host shales (2.9 % EqV<em>R</em>_o). Hopanes and steranes are detectable in both free and calcite-occluded hydrocarbons within these concretions, with concentrations of individual compounds ranging from 0.001 to 0.800 μg/g TOC, whereas kerogen-bound hydrocarbons lack detectable biomarkers. The results indicate that the two Cambrian carbonate concretions were formed mainly within the iron reduction and bacterial sulfate reduction zones, extending to depths of 10 to 38 m below the sediment-water interface. The OM within these concretions mainly inherited the initial unaltered signature of OM from the Qiongzhusi host shale. The carbonate concretions protected the internal OM from further thermal and secondary (e.g., biodegradation) alteration processes and might also prevent the formation of the conventional macromolecular skeletal kerogen manifested by the absence of bound biomarkers. The biomarkers, in both free and occluded forms, in the Cambrian carbonate concretions still retained their original source information, providing valuable insights into ancient biogeochemical processes during sediment burial and ancient seawater chemistry during the early Cambrian.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"197 ","pages":"Article 104876"},"PeriodicalIF":2.6,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417963","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":"Distribution and origin of higher diamondoids in the ultra-deep Paleozoic condensates of the Shunbei oilfield in the Tarim Basin, NW China","authors":"Rongzhen Qiao,&nbsp;Meijun Li,&nbsp;Donglin Zhang,&nbsp;Hong Xiao","doi":"10.1016/j.orggeochem.2024.104883","DOIUrl":"10.1016/j.orggeochem.2024.104883","url":null,"abstract":"<div><div>Higher diamondoids in the condensates of the Shunbei oilfield were analyzed using GC–MS. The findings indicate that the condensates in the Shunbei oilfield were subjected to a superimposed effect of secondary alterations, including biodegradation, hydrothermal alteration, evaporative fractionation, cracking, and TSR. High local concentrations of thiaadamantanes in oil may result from the interaction of H₂S, derived from Cambrian TSR, with Ordovician hydrocarbons, influenced by hydrothermal activities. Comprehensive analysis shows that TSR is local and limited in Ordovician reservoirs in the Shunbei oilfield and has no significant impact on oil chemistry. Comparative studies indicate that the diamondoid concentrations in condensates from the Shunbei oilfield have not been significantly impacted by biodegradation and evaporative fractionation. Parameters related to diamantanes can effectively characterize their geochemical characteristics and secondary alteration. A multi-parameter correlation heat map suggests that higher diamondoids in the condensates of the Shunbei oilfield are not due to high thermal evolution but have been altered by hydrothermal activity. The hydrothermal activity promotes the formation of higher diamondoids in the condensate. The higher diamondoids that are formed by hydrothermal activity offer a new perspective for studying hydrothermal processes. Additionally, this aids in studying the organic-inorganic interactions of ultra-deep organic fluids with their mineralogical and aqueous environments.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"197 ","pages":"Article 104883"},"PeriodicalIF":2.6,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417965","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 – August 2024","authors":"","doi":"10.1016/j.orggeochem.2024.104865","DOIUrl":"10.1016/j.orggeochem.2024.104865","url":null,"abstract":"","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"197 ","pages":"Article 104865"},"PeriodicalIF":2.6,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533616","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}