Organic Geochemistry最新文献

{"title":"First report of Early Permian Tasmanite oil shales in northern Pangea with global implications","authors":"Ruijie Zhang ,&nbsp;Jian Cao ,&nbsp;Wenxuan Hu ,&nbsp;Lizeng Bian ,&nbsp;Yuce Wang ,&nbsp;Bin Zhang ,&nbsp;Liuwen Xia ,&nbsp;Suping Yao ,&nbsp;Yong Tang","doi":"10.1016/j.orggeochem.2024.104736","DOIUrl":"https://doi.org/10.1016/j.orggeochem.2024.104736","url":null,"abstract":"<div><p>During the Late Paleozoic Ice Age (LPIA; particularly early Permian), organic material of the alga <em>Tasmanites</em> was extensively deposited in sediments of southern Gondwana, which formed the Tasmanite oil shales that have only been identified in Tasmania, Australia. It remains unclear whether other analogous geological records exist worldwide that formed at the same time, and the origin is enigmatic. This paper reports the first discovery of Tasmanite oil shales in northern Pangea, specifically in the Lucaogou Formation of the Junggar Basin, China, deposited during the Artinskian (<em>ca.</em> 290 Ma). The organic petrological features of <em>Tasmanites</em> are clearly visible, including thick-walled disks with tubes and radially arranged channels. These shales have markedly elevated C₂₈/C₂₉ steranes and tricyclic terpanes/hopanes ratios. Based on inorganic geochemical data, the salinity of the paleo-lake during deposition of the Tasmanite oil shale interval decreased abruptly from saline to brackish–freshwater. In addition, the pH changed from alkaline to nearly neutral, while the redox environment changed from anoxic to suboxic. Enhanced continental chemical weathering and the change in salinity of the paleo-lake occurred at the same time as global warming and large-scale glacier melting during the Artinskian, which promoted the habitat of the low-salinity tolerant <em>Tasmanites</em>. Our results provide new geological evidence for another occurrence of early Permian Tasmanite oil shales, indicating that <em>Tasmanites</em> flourishs and the associated oil shales may have been widely deposited at the end of the LPIA. The flourishment of <em>Tasmanites</em> archives biotic–environmental co-evolution.</p></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"188 ","pages":"Article 104736"},"PeriodicalIF":3.0,"publicationDate":"2024-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139435939","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":"Archaeal lipid biomarkers in near-surface sediments at a giant colony of the bivalve Calyptogena: Molecular records of a massive methane release event associated with methane hydrate dissociation","authors":"Susumu Sakata ,&nbsp;Urumu Tsunogai ,&nbsp;Masahiro Oba ,&nbsp;Tomomi Ujiie ,&nbsp;Manabu Tanahashi","doi":"10.1016/j.orggeochem.2024.104739","DOIUrl":"10.1016/j.orggeochem.2024.104739","url":null,"abstract":"<div><p>To investigate the possibility that dissociation of subsurface methane hydrate (MH) in the eastern Nankai Trough, offshore of Japan, led to the formation of a giant colony of the bivalve <em>Calyptogena</em> (currently mostly dead), the carbon isotope ratios (δ¹³C) of archaeal lipids and methane were measured in near-surface core sediments at Daini-Tenryu Knoll. The irregular variation of porewater methane δ¹³C with depth (from −75 ‰ to −26 ‰) suggested that originally low δ¹³C microbial methane was degraded in different proportions by anaerobic methane oxidation. Consistent with this inference, biomarkers of anaerobic methanotrophic archaea (ANME), namely, crocetane (2,6,11,15-tetramethylhexadecane), PMI (2,6,10,15,19-pentamethylicosane), and diethers (archaeol and hydroxyarchaeols), were detected in lipid extracts. The low diether δ¹³C values (−121 ‰ to −104 ‰) were characteristic of ANME, but less variable than the methane δ¹³C values, and the relationships between diethers and methane δ¹³C values deviated from regression lines derived using worldwide data from modern methane seep sites. In contrast, δ¹³C values of the ANME source methane predicted from those regression lines and the diether δ¹³C values agreed well with methane δ¹³C values in MH samples obtained by nearby deep drilling. This result strongly suggests that most of the diethers were produced by ANME that proliferated during a past massive methane release event associated with MH dissociation. The crocetane δ¹³C value, measured in a mixture with phytane and estimated from the correlation of the δ¹³C of the mixture with the mole fraction of crocetane, was about −127 ‰. More than half of the PMI δ¹³C values were greater than −100 ‰, suggesting the background presence of fossil PMI from methanogens.</p></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"188 ","pages":"Article 104739"},"PeriodicalIF":3.0,"publicationDate":"2024-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0146638024000044/pdfft?md5=52f943db7329db4ec61e14f4abecb261&pid=1-s2.0-S0146638024000044-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139462941","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":"High abundances of degraded triterpenoids in Miocene turbiditic sediments of south-central Hokkaido, Japan","authors":"Hiroyasu Asahi ,&nbsp;Ken Sawada","doi":"10.1016/j.orggeochem.2023.104671","DOIUrl":"https://doi.org/10.1016/j.orggeochem.2023.104671","url":null,"abstract":"<div><p>Aliphatic and aromatic degraded triterpenoids (TTs), including <em>des</em>-A and <em>des</em>-E TTs, were investigated in turbiditic and hemipelagic mudstones from the Miocene Kawabata Formation (Ishikari basin) and Abetsu and Nibutani formations (Hodaka basin) of south-central Hokkaido, Japan. <em>des</em>-A TTs with carbon skeletons of oleanane, ursane, and lupane are derived from angiosperms, while <em>des</em>-E TTs with hopane carbon skeletons are of bacterial origin. These compounds are thought to form through microbial degradation under dysoxic and anoxic conditions. We found that the concentrations and abundances of total degraded TTs, especially <em>des</em>-A TTs, relative to total organic carbon (TOC) were markedly higher in the Kawabata Formation despite significant levels in the Abetsu and Nibutani formations. These results clearly suggested that huge amounts of <em>des</em>-A TTs may have been transported to, and accumulated in, the Ishikari basin during the late Miocene. Degraded TT/TOC ratios are correlated with aquatic macrophyte <em>n</em>-alkane proxy (<em>P</em>aq) values in the Abetsu Formation. Higher <em>P</em>aq values are interpreted as indicating large contributions of aquatic, submerged or floating macrophytes, and are commonly observed in lake and pond environments. Thus, large amounts of degraded TTs were likely produced through the biodegradation of transported angiospermous TTs in dysoxic or anoxic environments, such as ponds and wetlands. Furthermore, we assumed that organic matter deposited in the Hidaka basin was transported from wetlands and marsh areas, especially floodplain lakes, of paleo-Hidaka Island. The class distributions of degraded TTs varied among samples from these formations. The higher relative abundances of <em>des</em>-A lupanes in the Ishikari basin (Kawabata Formation) suggest that TTs were supplied from mountainous forested areas, where lupenoid-producing woody plant taxa may occur. Meanwhile, less abundant <em>des</em>-A lupanes in the Hidaka basin (Abetsu and Nibutani formations) suggest little or no supply of TTs from mountainous forested areas.</p></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"188 ","pages":"Article 104671"},"PeriodicalIF":3.0,"publicationDate":"2024-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139111515","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 – October 2023","authors":"","doi":"10.1016/j.orggeochem.2023.104704","DOIUrl":"10.1016/j.orggeochem.2023.104704","url":null,"abstract":"","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"187 ","pages":"Article 104704"},"PeriodicalIF":3.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S014663802300150X/pdfft?md5=c909a36e2c2e320a341de4e9f2ec535f&pid=1-s2.0-S014663802300150X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138552888","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":"Robert Alexander Obituary died 28th July 2023 (82 years)","authors":"","doi":"10.1016/j.orggeochem.2023.104692","DOIUrl":"10.1016/j.orggeochem.2023.104692","url":null,"abstract":"","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"187 ","pages":"Article 104692"},"PeriodicalIF":3.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0146638023001389/pdfft?md5=ffe4e990ec2442e5040158fb5ef523a7&pid=1-s2.0-S0146638023001389-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139020749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geochemistry Articles – September 2023","authors":"","doi":"10.1016/j.orggeochem.2023.104703","DOIUrl":"10.1016/j.orggeochem.2023.104703","url":null,"abstract":"","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"187 ","pages":"Article 104703"},"PeriodicalIF":3.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0146638023001493/pdfft?md5=eab345073f953303bc23ca32c0e5dd73&pid=1-s2.0-S0146638023001493-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138581333","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":"Paleoceanographic importance of tri- and di-unsaturated alkenones through the early phase of Cretaceous Oceanic Anoxic Event 2 from southern high latitudes of the proto-Indian Ocean","authors":"Takashi Hasegawa ,&nbsp;Akiko S. Goto","doi":"10.1016/j.orggeochem.2023.104722","DOIUrl":"10.1016/j.orggeochem.2023.104722","url":null,"abstract":"<div><p>Alkenones are biomarkers derived exclusively from species of haptophyte algae. The relative abundance of di- to tri-unsaturated C₃₇ alkenones expressed as U^K'₃₇ is widely applied as a sea surface paleotemperature proxy for Cenozoic marine sediments. However, the absence of alkatrienones prior to the Eocene has precluded application of the U^K'₃₇ proxy for assessment of Cretaceous paleoclimates. Herein, we report a C₄₀ alkatrienone (tetraconta-9<em>E</em>, 16<em>E</em>, 23<em>E</em>-trien-3-one; C_40:3 Et) in deep-sea sediments from southern high latitudes (International Ocean Discovery Program: IODP site U1516). This discovery extends the geologic record of alkatrienones to the late Cenomanian, ∼70 million years earlier than previous reports. The parallel occurrence of higher abundances of a C₄₀ alkadienone (tetraconta-16<em>E</em>, 23<em>E</em>-dien-3-one; C_40:2 Et) allowed calculation of the U^K’₄₀ unsaturation index, comparable to U^K’₃₇. Stratigraphic variations in the δ¹³C of C_40:2 Et revealed an elevated (∼1.5 ‰) positive carbon isotope excursion (CIE) relative to those observed in carbonate from other OAE2 sequences likely reflecting a decrease in global <em>p</em>CO₂. The U^K’₄₀ profile suggests a concurrent drop in sea surface temperature associated with the decline in <em>p</em>CO₂ during the early phase of OAE2. The timing of these environmental perturbations in the southern high latitude of the proto-Indian Ocean suggests they were triggered by volcanism associated with large igneous province (LIP) formation.</p></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"188 ","pages":"Article 104722"},"PeriodicalIF":3.0,"publicationDate":"2023-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139051132","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":"The occurrence and geochemical origin of 9-alkyl HDBTs substituted by long isoprenoid alkyl chains in crude oil","authors":"Jianxun Wu ,&nbsp;Abdelrahman A. Hamid ,&nbsp;Weilai Zhang ,&nbsp;Shuofan Li ,&nbsp;Yahe Zhang ,&nbsp;Yuhong Liao ,&nbsp;Quan Shi","doi":"10.1016/j.orggeochem.2023.104721","DOIUrl":"10.1016/j.orggeochem.2023.104721","url":null,"abstract":"<div><p>1,1,4a,6-tetramethyl-9-alkyl-1,2,3,4,4a,9b-hexahydrodibenzo[b,d]thiophene (9-alkyl HDBT) was initially found in highly desulfurized diesel oils. This and related organic sulfur compounds (OSCs) have a special shielding structure that make them extremely resistant to hydrodesulfurization. The structure of 9-alkyl HDBTs is likely directly inherited from biological precursors related to terpenoids, but their origins have not been determined. In this study, OSCs were isolated from a low sulfur crude oil from the Junggar Basin in China by the methylation/demethylation method and characterized by gas chromatography-mass spectrometry. A series of 9-alkyl HDBTs substituted with long isoprenoid alkyl chains were identified in the OSCs. Raney nickel desulfurization was conducted to assist the structural identification. The presence of 9-alkyl HDBTs with a <em>β</em>-carotene carbon skeleton and the predominance in specific carbon numbers of alkyl-substituted 9-alkyl HDBTs support a carotenoid origin of such OSCs. Possible geochemical pathways are proposed for the formation of these OSCs via <em>β</em>-carotene, involving processes such as sulfur incorporation, cyclization, aromatization, hydrogenation, and cleavage.</p></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"188 ","pages":"Article 104721"},"PeriodicalIF":3.0,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139030296","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":"Robert Alexander Obituary died 28th July 2023 (82 years)","authors":"","doi":"10.1016/j.orggeochem.2023.104692","DOIUrl":"https://doi.org/10.1016/j.orggeochem.2023.104692","url":null,"abstract":"Abstract not available","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"79 1","pages":""},"PeriodicalIF":3.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139030346","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":"Possible application of bicyclic sesquiterpanes to evaluate the thermal maturity of oils. A study of Kamchatka and Chukotka oils from Cenozoic deposits, Russia","authors":"Irina Konopleva","doi":"10.1016/j.orggeochem.2023.104717","DOIUrl":"https://doi.org/10.1016/j.orggeochem.2023.104717","url":null,"abstract":"<div><p>The distribution of bicyclic sesquiterpanes in crude oils was studied to assess the applicability of the sesquiterpane ratios as maturity parameters. GC–MS analysis was conducted on ten oil samples that were generated in Miocene-Paleogene deposits located within the Kamchatka Peninsula and southeast Chukotka, the Russian Far East. During catagenesis, there is a shift in the distribution of sesquiterpanes with increasing thermal maturity, e.g., a decrease of the relative content of C₁₆ homodrimanes towards an increase of C₁₅ drimanes and C₁₄ sesquiterpanes. New maturity indices, based on sesquiterpanes, correlate well with commonly used maturity indicators, such as a methylphenanthrene index (MPI-1) and a methyldibenzothiophene ratio (MDR) (the <em>R</em>² value greater than 0.746). Since C₁₄ sesquiterpanes can arise as a product of thermolysis of higher homologues or may be derived from other organic sources, it is not included in one of the new indices.</p></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"187 ","pages":"Article 104717"},"PeriodicalIF":3.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0146638023001638/pdfft?md5=372d844f08fc5004f1ac1d097d51b5df&pid=1-s2.0-S0146638023001638-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138656603","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}