Pub Date : 2024-11-29DOI: 10.1016/j.orggeochem.2024.104901
Congsheng Bian , Shiju Liu , Wei Liu , Xiong Cheng , Xin Liu , Jin Dong , Rui Wang , Yongxin Li , Ming Guan , Qianhui Tian , Wenzhi Zhao
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.
{"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 , Shiju Liu , Wei Liu , Xiong Cheng , Xin Liu , Jin Dong , Rui Wang , Yongxin Li , Ming Guan , Qianhui Tian , 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}
Pub Date : 2024-11-19DOI: 10.1016/j.orggeochem.2024.104884
Kun He , Xiaomei Wang , Chunlong Yang , Linfeng Xie , Shuichang Zhang
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 Fe1-xS (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.
{"title":"C/H isotope fractionation of hydrocarbon gases from hydrogenation of organic matter: Insights from hydrothermal experiments","authors":"Kun He , Xiaomei Wang , Chunlong Yang , Linfeng Xie , 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 (H<sub>2</sub>O and H<sub>2</sub>) play a significant role in hydrocarbon (HC) generation in sedimentary basins, and the effects of hydrogenation of organic matter (OM) by H<sub>2</sub>O/H<sub>2</sub> 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 H<sub>2</sub>O (Group 2), and (3) kerogen, H<sub>2</sub>O, and Fe<sub>1-</sub><em><sub>x</sub></em>S (Group 3). Groups 2 and 3 were designed to simulate hydrogenation of OM by H<sub>2</sub>O and H<sub>2</sub>, 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 H<sub>2</sub> produces HC gases with smaller <sup>13</sup>C fractionation and more negative δ<sup>2</sup>H values compared to hydrogenation by H<sub>2</sub>O. These findings suggest distinct mechanisms for HC gas generation during H<sub>2</sub>-OM and H<sub>2</sub>O-OM reactions. Further analysis demonstrates that the equilibrium isotope effect (EIE) governs <sup>13</sup>C and <sup>2</sup>H isotope fractionation during hydrogenation of OM by H<sub>2</sub>. Importantly, the EIE for <sup>2</sup>H isotope fractionation of H<sub>2</sub>O-H<sub>2</sub>, CH<sub>4</sub>-H<sub>2</sub>, and OM-H<sub>2</sub> is evaluated under both experimental and geological conditions. This study provides crucial insights into the significant influence of hydrogenation of OM by H<sub>2</sub> on the generation and C/H isotopic fractionation of HC gases, as well as the evolution and preservation of H<sub>2</sub> 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}
Carbazoles in Ordovician ultra-deep marine oil from the FI17 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[a]carbazole/(benzo[a]carbazole + benzo[c]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 %VRE (the vitrinite reflectance equivalent converted from MPI1 and MPR) when %VRE is <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 %VRE 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 %VRE. The maturity of marine oil can be calculated using the formulas %Rc (the vitrinite reflectance equivalent calculated from MPI1) = −0.0335(1, 8-DMCa/1-ECa) + 1.2902 or %Rc1 (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.
{"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 , Hongwei Ping , Honghan Chen , Zulin Chen , Yanqiu Zhang , Zhou Xie , Yintao Zhang , 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<sub>I</sub>17 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 MPI<sub>1</sub> and MPR) when %<em>VRE</em> is <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 MPI<sub>1</sub>) = −0.0335(1, 8-DMCa/1-ECa) + 1.2902 or <em>%R</em>c<sub>1</sub> (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}
Pub Date : 2024-11-10DOI: 10.1016/j.orggeochem.2024.104881
Bin Cheng , Zhiwei Wei , Yiman Zhang , Hanyu Deng , Yuxian Li , Haozhe Wang , Zewen Liao
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-n-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. tran-1-methyldecalin (1-MD), 5-methyltetraline (5-MT) and 1-MN, the 2H enrichment follows the order δ2H1-MD < δ2H5-MT < δ2H1-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.
{"title":"Hydrogen isotope fractionation during aromatization to form alkylnaphthalene: Insights from pyrolysis experiments of 1-n-butyldecalin","authors":"Bin Cheng , Zhiwei Wei , Yiman Zhang , Hanyu Deng , Yuxian Li , Haozhe Wang , 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 <sup>2</sup>H enrichment follows the order δ<sup>2</sup>H<sub>1-MD</sub> < δ<sup>2</sup>H<sub>5-MT</sub> < δ<sup>2</sup>H<sub>1-MN</sub> 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 <sup>2</sup>H, resulting in a higher δ<sup>2</sup>H value of higher aromatic-ring-number hydrocarbon than that of a lower aromatic-ring-number at low aromatization. However, <sup>2</sup>H 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}
Pub Date : 2024-11-09DOI: 10.1016/j.orggeochem.2024.104878
Jingkun Zhang , Jian Cao , Wenjun He
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 > Fe > Mn, whereas that for the substitution of Ca is Mn > Fe > 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.
人们对石油体系中痕量金属的迁移机制知之甚少，这限制了我们对有机-无机相互作用及其在石油来源追踪中应用的了解。基于金属卟啉的分子模型，利用密度泛函理论进行的数值模拟显示，卟啉质子化与石油中的痕量金属脱钩有关。痕量金属很容易与弱质子化的卟啉 N 形成共价键，形成稳定的化合物。然而，在流体 pH 值较低时，由于 N 的质子化作用增强，激活了与 O2- 离子键的形成，金属可能会脱钩。释放出的金属可能会通过 Ca 的置换作用被固定在自生方解石胶结物（ACC）储层中。镁、锰和铁的解耦顺序为镁 > 铁 > 锰，而 Ca 的置换顺序为锰 > 铁 > 镁，这反映了有机-无机相互作用的复杂性，也表明了金属在石油来源指纹识别中的潜在应用。对中国准噶尔盆地南部的案例研究表明，ACC 的锰、铁和镁富集可分别提供古生代、中生代和新生代石油系统的指示，为石油盆地的油源追踪提供了一种潜在的新方法。
{"title":"Porphyrin protonation induces decoupling of trace metals in petroleum","authors":"Jingkun Zhang , Jian Cao , 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 O<sup>2−</sup>. 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 > Fe > Mn, whereas that for the substitution of Ca is Mn > Fe > 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}
Pub Date : 2024-11-02DOI: 10.1016/j.orggeochem.2024.104894
Wenna Liu , Wanglu Jia , Qiang Wang , Jian Chen , Jinbu Li , Ping’an Peng
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 > alkane mixture > 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), n-heptane (nC7), and toluene (Tol).
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., nC7/MCH, Tol/nC7) 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, nC7, 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.
有机化合物在蒸发过程中的同位素分馏是稳定同位素领域最关键的问题之一。近年来，石油中轻烃（LHs）的氢（H）同位素组成在石油成因研究中越来越受到关注。然而，与碳（C）同位素相比，我们对各类 LHs 在蒸发过程中的氢同位素分馏模式和影响因素的了解十分有限。在本研究中，我们在恒温条件下对单一化合物、烷烃混合物和轻油这三种系统中的 LHs 进行了蒸发实验。我们评估了残留液相中单个 LHs 的含量和 H 同位素组成。我们结合碳同位素对 H 同位素分馏程度和影响因素进行了研究。随着蒸发的进行，LHs 的 H 同位素分馏呈现出 "反同位素分馏 "特征（残留 LHs 中 D 的消耗），这与 C 同位素分馏相反。同位素分馏的程度受蒸发系统、化合物分子量及其结构的影响。(1）H 和 C 的同位素分馏程度依次降低：轻油 > 烷烃混合物 > 单一化合物体系。这种差异可能与蒸发体系的不饱和程度和蒸发基质有关。(2）对于同一蒸发体系中结构相似的 LHs，由于样品池的缓冲作用，H 同位素分馏程度随分子量的增加而增加，C 同位素分馏程度则随分子量的增加而减小。(3) 对于具有相同 C 数的 LHs，甲基环己烷（MCH）的蒸发率和同位素分馏程度低于其他 C7 化合物，如 3-甲基己烷（3-MH）、正庚烷（nC7）和甲苯（Tol）。将同一化合物的 H 和 C 同位素组成与常用的 LHs 分子比（如 nC7/MCH、Tol/nC7）结合起来，可以全面区分控制油类形成的三个关键过程：蒸发、热成熟和生物降解。此外，C7 LHs（3-MH、nC7 和 Tol）之间的 H 同位素组成差异可能会因蒸发而改变，但其变化范围要比来源差异造成的变化范围小得多。因此，将 H 和 C 同位素结合起来，在石油来源特征描述方面可能大有可为。
{"title":"Influencing factors of hydrogen isotopic fractionation of light hydrocarbons during evaporation and implications","authors":"Wenna Liu , Wanglu Jia , Qiang Wang , Jian Chen , Jinbu Li , 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 > alkane mixture > 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 C<sub>7</sub> compounds like 3-methylhexane (3-MH), <em>n</em>-heptane (<em>n</em>C<sub>7</sub>), 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>C<sub>7</sub>/MCH, Tol/<em>n</em>C<sub>7</sub>) enables full differentiation of three critical processes controlling oil formation: evaporation, thermal maturation, and biodegradation. Furthermore, the differences in H isotopic compositions between C<sub>7</sub> LHs (3-MH, <em>n</em>C<sub>7</sub>, 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}
Pub Date : 2024-10-20DOI: 10.1016/j.orggeochem.2024.104886
Oliver C. Moore , Amy D. Holt , Laura A. Richards , Amy M. McKenna , Robert G.M. Spencer , Dan J. Lapworth , David A. Polya , Jonathan R. Lloyd , Bart E. van Dongen
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.
亚洲各地的含水层都受到了地生砷（As）通过微生物还原含砷的氢氧化铁（III）矿物而释放到地下水中的影响，严重影响了水质。地下水溶解有机物（DOM）可能是砷释放的关键，主要作为电子供体或电子快车。本研究利用光学分析和超高分辨率质谱仪，在柬埔寨干丹省的易砷含水层中，通过不同主岩性（粘土和砂土为主）的钻孔，研究了地下水 DOM 的来源和组成。地下水和地表水 DOM 组成与砷浓度相关，以推断 DOM 在促进砷释放方面的潜在作用。光学和分子水平分析表明，地下水样本中的陆源 DOM 总体上占主导地位，与沙为主的岩性相比，粘土中脂肪族化合物的新鲜度指数和相对丰度 (RA) 较高。与地表水相比，地下水 DOM 的 O/C 比和碳的名义氧化态相对较低（地下水和地表水的 O/C 比和碳的名义氧化态分别为 -0.19 至 -0.13，而地下水和地表水的 O/C 比和碳的名义氧化态分别为 0.04），脂肪族化合物的相对丰度（%RA）较低，而富含羧基的脂环族分子的相对丰度（%RA）较高，这表明 DOM 在渗入含水层后经过了微生物处理。这两个地点的砷浓度与 DOM 色氨酸：类富勒烯荧光和脂肪族化合物的%RA 呈负相关，这可能表明微生物在释放砷的同时也降解了可生物降解的 DOM，这与其作为电子供体源的作用是一致的。总之，这些数据支持 DOM 成分是控制微生物介导的砷释放的重要因素。
{"title":"Characterisation of dissolved organic matter in two contrasting arsenic-prone sites in Kandal Province, Cambodia","authors":"Oliver C. Moore , Amy D. Holt , Laura A. Richards , Amy M. McKenna , Robert G.M. Spencer , Dan J. Lapworth , David A. Polya , Jonathan R. Lloyd , 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}
Pub Date : 2024-10-10DOI: 10.1016/j.orggeochem.2024.104876
Xinyan Fang , Qing Zhang , Liangliang Wu , Ansong Geng , Shufen Liu , Pufan Wang , Xiao Liang
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 % EqVRo) is relatively low compared to their adjacent host shales (2.9 % EqVRo). 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.
碳酸盐凝块被广泛用于古气候、古环境和古生物学研究，甚至用于火星上潜在生命的研究。中新生代碳酸盐岩凝块（热成熟度相对较低）中的这些岩石学、元素、同位素和脂质生物标记信号可以有效地保存其寄主沉积物/岩石沉积过程中海水条件和底栖生态系统的细节。然而，对高成熟度条件下的前寒武纪-寒武纪碳酸盐岩凝结物的此类研究仍然很少，这些古老的碳酸盐岩凝结物保留其原始生物信息的能力仍不确定。为此，本研究利用华南扬子地块下寒武统琼珠寺组的两个寒武纪碳酸盐岩凝块，分别从其中心、过渡层和边缘及其邻近的黑色页岩中采集样品，对这两个碳酸盐岩凝块进行了研究。结合有机和无机地球化学分析，阐明了这些古寒武纪碳酸盐岩凝块中有机质（OM）的来源和保存过程。结果表明，与邻近的主页岩（2.9% EqVRo）相比，这些凝块中有机质的热成熟度（1.8% EqVRo）相对较低。在这些凝结体内的游离碳氢化合物和方解石包涵碳氢化合物中均可检测到庚烷和甾烷，单个化合物的浓度范围为 0.001 至 0.800 μg/g TOC，而与角质结合的碳氢化合物则缺乏可检测到的生物标志物。结果表明，两个寒武纪碳酸盐凝块主要形成于铁还原区和细菌硫酸盐还原区，延伸至沉积物-水界面以下 10 至 38 米深处。这些凝结体内的 OM 主要继承了琼珠寺主页岩最初未改变的 OM 特征。碳酸盐凝块保护了内部的 OM，使其免受进一步的热和二次（如生物降解）改变过程的影响，也可能阻止了传统的大分子骨架角质的形成，表现为没有结合的生物标志物。寒武纪碳酸盐凝块中的生物标志物，无论是游离形式还是闭合形式，仍然保留了其原始来源信息，为了解沉积物埋藏过程中的古生物地球化学过程和寒武纪早期的古海水化学过程提供了宝贵的资料。
{"title":"Origin and preservation mechanisms of organic matter in carbonate concretions from Lower Cambrian black shales in South China","authors":"Xinyan Fang , Qing Zhang , Liangliang Wu , Ansong Geng , Shufen Liu , Pufan Wang , 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><sub>o</sub>) is relatively low compared to their adjacent host shales (2.9 % EqV<em>R</em><sub>o</sub>). 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}
Pub Date : 2024-10-10DOI: 10.1016/j.orggeochem.2024.104883
Rongzhen Qiao, Meijun Li, Donglin Zhang, Hong Xiao
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.
采用气相色谱-质谱法分析了顺北油田凝析油中的高菱形酮。研究结果表明，顺北油田的凝析油受到了二次变化的叠加影响，包括生物降解、热液变化、蒸发分馏、裂解和 TSR。寒武纪 TSR 产生的 H2S 与奥陶纪碳氢化合物受热液活动的影响相互作用，可能导致石油中噻金刚烷的局部高浓度。综合分析表明，TSR 在顺北油田奥陶系储层中是局部的、有限的，对石油化学性质没有重大影响。对比研究表明，顺北油田凝析油中的二烷烃浓度没有受到生物降解和蒸发分馏的明显影响。与二烷烃相关的参数可以有效地描述其地球化学特征和二次改变。多参数相关热图表明，顺北油田凝析油中较高的二烷烃不是由于高热演化造成的，而是热液活动改变的。热液活动促进了凝析油中较高金刚石的形成。由热液活动形成的高等金刚烷为研究热液过程提供了一个新的视角。此外，这还有助于研究超深层有机流体与其矿物和水环境之间的有机-无机相互作用。
{"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, Meijun Li, Donglin Zhang, 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 H<sub>2</sub>S, 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}
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