Organic Geochemistry最新文献

{"title":"Quantification and isotopic characterization of benzene polycarboxylic acids (BPCA)-derived black carbon in deep oceanic sediments: Towards assessing pyrogenic inputs from marine sources","authors":"N. Penalva-Arias ,&nbsp;O. Teruel ,&nbsp;M. Raja ,&nbsp;A. Rosell-Melé ,&nbsp;J. Villanueva","doi":"10.1016/j.orggeochem.2024.104811","DOIUrl":"https://doi.org/10.1016/j.orggeochem.2024.104811","url":null,"abstract":"<div><p>Methodologies based on benzene polycarboxylic acids (BPCA) selectively target the polymeric aromatic fraction of black carbon (BC) and are considered adequate to quantify pyrogenic inputs in environmental samples such as soils, lakes, and marine dissolved organic carbon. However, the usefulness of these methodologies to quantify BPCA-derived BC in deep-sea sediments has not been fully evaluated. In this manuscript we describe and validate a procedure to quantify BPCAs in deep oceanic sediments with very low organic carbon content. The resulting analytical procedure has produced reproducible quantitative data for BPCAs over a period of 10 months (coefficient of variation, CV = 6.4 − 6.6%). The stable carbon isotopes (δ¹³C) of BC_BPCA have been characterized using an LC Isolink™-irMS system with an accuracy better than 0.5‰. The quantitative and isotopic composition of several marine sediments has been characterized to investigate the relative contributions of marine/diagenetic and continental/pyrogenic sources to the BC accumulated in oceanic sediments from different contexts, ranging from upwelling systems to remote oceanic locations. Overall, a significant fraction of the sedimentary BC is of marine origin and should be considered in inventories of pyrogenic materials accumulated in the world oceans. However, the continental/pyrogenic sources can be largely dominant in marine settings with large inputs of pyrogenic materials.</p></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"193 ","pages":"Article 104811"},"PeriodicalIF":3.0,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0146638024000767/pdfft?md5=f19b6c6d578f2a575981ee0e67868738&pid=1-s2.0-S0146638024000767-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141291701","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":"Investigating the application of organic geochemical techniques to tropical Anjohibe (Madagascar) stalagmites","authors":"Robin R. Dawson ,&nbsp;Isla S. Castañeda ,&nbsp;Stephen J. Burns ,&nbsp;Jeffrey M. Salacup ,&nbsp;Nick Scroxton ,&nbsp;David McGee ,&nbsp;Peterson Faina ,&nbsp;Laurie R. Godfrey ,&nbsp;Lovasoa Ranivoharimanana","doi":"10.1016/j.orggeochem.2024.104810","DOIUrl":"10.1016/j.orggeochem.2024.104810","url":null,"abstract":"<div><p>Speleothem stable carbon isotopes (δ¹³C_carb) are used to reconstruct past environments, but are a complex signal of karst, soil and plant processes. To help untangle these signals, we used plant waxes, their carbon isotopic values (δ¹³C_wax) and polycyclic aromatic hydrocarbons (PAHs) extracted from stalagmites to evaluate plant photosynthetic pathway (C₃ vs C₄) and biomass burning above a cave. Our test case investigates stalagmites from Anjohibe in Madagascar where at around 1000 CE multiple δ¹³C_carb records increase by ∼ 8–10 ‰. This suggests that humans transformed the local landscape from C₃ vegetation to C₄ grasses through agropastoral practices, which rely on burning to promote grass growth. We evaluated different protocols to remove contamination, finding higher biomarker yields after polishing off the surface of the stalagmite versus ultrasonic pre-cleaning in solvent. Anjohibe stalagmites include <em>n-</em>alkanes from trees and grasses; however, bulk organic δ¹³C and δ¹³C_wax from samples dated to after the transition to the modern C₄ landscape yield values suggesting C₃ vegetation. This is likely due to a disproportionally higher contribution of C₃ waxes to the overall <em>n</em>-alkane signal. PAHs are present in the stalagmite but do not match the types found in overlying soils and further testing is required to determine their source. We find that δ¹³C values of bulk organic carbon, or plant waxes extracted from stalagmites, should be interpreted with caution as the proportion of plant matter on the landscape does not necessarily equate to the proportion of organic molecules produced by those plants or preserved in the sedimentary record.</p></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"195 ","pages":"Article 104810"},"PeriodicalIF":2.6,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0146638024000755/pdfft?md5=eba34ccd10bd13b84d56a1a0223e2c72&pid=1-s2.0-S0146638024000755-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141781948","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":"On the validity of position specific carbon isotopic analysis (PSIA) of propane","authors":"Clifford C. Walters (Editor-in-Chief)","doi":"10.1016/j.orggeochem.2024.104799","DOIUrl":"10.1016/j.orggeochem.2024.104799","url":null,"abstract":"","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"192 ","pages":"Article 104799"},"PeriodicalIF":3.0,"publicationDate":"2024-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141039996","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":"Contribution of abiotic methane polymerization of C2+ hydrocarbons in highly mature natural gas reservoirs","authors":"Yun Li ,&nbsp;Wenmin Jiang ,&nbsp;Wen Liu ,&nbsp;Yongqiang Xiong ,&nbsp;Ping'an Peng","doi":"10.1016/j.orggeochem.2024.104798","DOIUrl":"https://doi.org/10.1016/j.orggeochem.2024.104798","url":null,"abstract":"<div><p>The formation and evolution of thermogenic gases were investigated using a combination of intermolecular and intramolecular isotope analyses of 32 natural gas samples collected from the Sichuan and Tarim basins (China) and the Arkoma Basin (USA). Three evolution stages (I–III) were identified: In stage I, hydrocarbon gases are produced through thermal decomposition of organic matter, and kinetic isotope effects in C–C bond breakage control their isotopic distributions; In stage II, C₂–C₅ hydrocarbons crack with increasing thermal maturity, with their formation and decomposition tending toward thermodynamic equilibrium, and at the end of this stage, the intermolecular and intramolecular isotopic compositions of gaseous hydrocarbons are in thermodynamic equilibrium; A remarkable feature of stage III is the surface-catalyzed abiotic polymerization of methane, which provides a critical origin of C₂₊ hydrocarbons in this stages and leads to isotopic anomalies in C₂₊ hydrocarbons, including the reversal of δ¹³C distributions of C₁–C₃ and the reverse evolution trend of SP value of propane (i.e., tending to be positive). The contribution of C₂₊ hydrocarbons from the abiotic polymerization of methane can be determined based on a two-end member model. C₂₊ hydrocarbons in the Changning shale gases are all generated from abiotic methane polymerization, and the contribution ratio in the Weiyuan shale gases is about 85 %, while, the contribution of C₂₊ hydrocarbons in dry gases from the Tarim Basin formed by this way is no more than 55 %. High methane abundance, high temperature, and abundant catalyst are beneficial to abiotic methane polymerization.</p></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"192 ","pages":"Article 104798"},"PeriodicalIF":3.0,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140947548","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":"Discussion on the studies of position-specific carbon isotopes of propane by Li et al. (2018), Zhang et al. (2022) and Shuai et al. (2023)","authors":"Juske Horita","doi":"10.1016/j.orggeochem.2024.104795","DOIUrl":"https://doi.org/10.1016/j.orggeochem.2024.104795","url":null,"abstract":"<div><p>In a series of recent publications in <em>Organic Geochemistry</em> and elsewhere, investigators from State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry and their collaborators have reported position-specific δ¹³C of propane obtained from natural reservoirs and pyrolysis experiments. Based solely on the very negative Δ_C-T values (δ¹³C_center – δ¹³C_terminal), ranging from −7 to −10 ‰, they advocated for abiogenic origins of the propanes from sedimentary settings (shale and coal deposits). However, they never demonstrated accuracy of the data and it is likely that correct Δ_C-T values for these propanes are close to zero ‰. Therefore, their discussion and interpretation in terms of geochemical processes, including a putative abiogenic origin, are not substantiated.</p></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"192 ","pages":"Article 104795"},"PeriodicalIF":3.0,"publicationDate":"2024-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140924492","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":"Reply to “Discussion on the studies of position-specific carbon isotopes of propane by Li et al. (2018), Zhang et al. (2022) and Shuai et al. (2023)”","authors":"Yun Li ,&nbsp;Yongqiang Xiong ,&nbsp;Yanhua Shuai","doi":"10.1016/j.orggeochem.2024.104797","DOIUrl":"https://doi.org/10.1016/j.orggeochem.2024.104797","url":null,"abstract":"","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"192 ","pages":"Article 104797"},"PeriodicalIF":3.0,"publicationDate":"2024-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140924424","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":"Early stages of Type I-S kerogen formation revealed by Rock-Eval® 7S analysis of sediment from a modern halo-alkaline lake (Dziani Dzaha, Mayotte)","authors":"","doi":"10.1016/j.orggeochem.2024.104794","DOIUrl":"10.1016/j.orggeochem.2024.104794","url":null,"abstract":"<div><p>The Dziani Dzaha (Mayotte Islands, Indian Ocean) is a small, shallow, saline and hyperalkaline maar lake. Its surface waters are characterized by intense primary production, inducing the waters below 2 m depth to remain aphotic and anoxic all year round, at least until 2017, when a ∼5 m-long core was taken from the center of the lake. The recovered sediments were described and sampled at high resolution. They consist of laminated microbial mats, mixed with carbonate lenses or nodular beds, and rare silty detrital facies. The inorganic and organic carbon contents of 160 samples were analyzed using the Rock-Eval® method, including the Rock-Eval® 7S device which quantifies both total organic sulfur and total sulfur content, in addition to conventional Rock-Eval parameters. The Dziani Dzaha sediments are characterized by high TOC content (8.5 wt% on average and up to 27.9 wt%) and variable inorganic carbon content. HI values average 630 mg HC/g TOC and reach up to 834 mg HC/g TOC. TS content varies from 0.3 to 3.6 wt%, with TSorg/TOC ratios close to 0.01 at the top of the core and fluctuating downcore between 0.02 and 0.05. Interestingly, the pyrolysis thermal stability of sulfurized organic matter increases with depth, and the highest HI values are associated with highest Sorg content, sulfurization of organic matter being generally accompanied by reductive processes. The hydrogen- and organic-sulfur-rich sediments of Dziani Dzaha can be considered modern analogues of Type I and I-S petroleum source rock deposits, such as the Eocene Green River shales and Kimmeridgian Orbagnoux laminites, with remarkable facies and geochemical similarities. (258 words)</p></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"195 ","pages":"Article 104794"},"PeriodicalIF":2.6,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141023904","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":"Direct evidence of gas flushing oil in deep reservoirs: Insight from integrated fluid inclusion analyses","authors":"Xinzhuo Wei ,&nbsp;Keyu Liu ,&nbsp;Wenfang Yuan ,&nbsp;Peng Yang ,&nbsp;Lu Zhou ,&nbsp;Jianliang Liu ,&nbsp;Haijun Yang ,&nbsp;Xiujian Ding","doi":"10.1016/j.orggeochem.2024.104778","DOIUrl":"https://doi.org/10.1016/j.orggeochem.2024.104778","url":null,"abstract":"<div><p>Gas flushing of oil has been proposed as an essential process for forming some condensate gas reservoirs based on laboratory experiments and modeling but such a process has rarely been documented in subsurface reservoirs. Here, we report a unique type of yellow-ringed oil inclusions (<em>YROIs</em>) discovered from a deep reservoir in the Kuqa Foreland Basin, Western China that recorded the gas flushing of oil process in the subsurface. The occurrence, composition, phase state and PVT conditions of <em>YROIs</em> during trapping were investigated using a suite of fluid inclusion analytical methods including fluid inclusion petrography, microthermometry, fluorescence spectroscopy, PVT modeling and molecular composition analysis.</p><p><em>YROIs</em> found in the reservoir are three-phase (solid–liquid-vapor) fluid inclusions at room temperature with solid rings of 2–3 μm thickness and estimated volume percentages varying between 5 % and 15 %. When heated the solid ring starts to melt at around 46 °C and homogenized with the liquid phase at or above their corresponding homogenization temperatures of coeval aqueous inclusions. <em>YROIs</em> have fluorescence spectral peaks between 530 nm and 550 nm and an elevated spectral shoulder around 650 nm when measured at room temperature; but most spectra show a distinct “blue shift” and an absence of the 650 nm shoulder when measured at their homogenization temperatures. Some <em>YROIs</em> with thick yellow rings show dual spectral peaks at 570 nm and 630 nm at room temperature and their spectral peaks do not change when remeasured at their homogenization temperatures. Molecular compositions derived from synchronous fluorescence spectra and GC-MS analysis suggest that the compositions of <em>YROIs</em> are rich in polyaromatic compounds. PVT modeling indicates that <em>YROIs</em> were trapped under high pressure conditions with a pressure exceeding 50 % of the corresponding hydrostatic pressure.</p><p><em>YROIs</em> are interpreted to have been trapped under an elevated temperature and overpressure condition (around 110 °C and 60 MPa) relating to an intensive (wet) gas flushing of an early-charged wax-rich oil. When light hydrocarbon components in the reservoir oil were partially removed by gas, the wax/resin components rich in polyaromatic hydrocarbon compounds may precipitate due to physio-chemical fractionation. <em>YROIs</em> were entrapped in subsurface from a heterogeneous hydrocarbon fluid containing variable amounts of wax/resin colloids, which subsequently coalesce to form solid rings adhering to the inner wall of oil inclusions at room temperature. The presence of yellow-ringed oil inclusions in a reservoir may be indicative of a rapid gas flushing of waxy oil under high pressure, and their minimum homogenization temperature may approximate their trapping temperature.</p></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"192 ","pages":"Article 104778"},"PeriodicalIF":3.0,"publicationDate":"2024-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140825287","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 – March 2024","authors":"","doi":"10.1016/j.orggeochem.2024.104779","DOIUrl":"https://doi.org/10.1016/j.orggeochem.2024.104779","url":null,"abstract":"","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"192 ","pages":"Article 104779"},"PeriodicalIF":3.0,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141164181","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 global distribution of Isoprenoidal Glycerol Dialkyl Diethers (isoGDDs) is consistent with a predominant degradation origin","authors":"Joe S. Hingley ,&nbsp;César C. Martins ,&nbsp;Chloe Walker-Trivett ,&nbsp;Jennifer K. Adams ,&nbsp;Sebastian Naeher ,&nbsp;Christoph Häggi ,&nbsp;Sarah J. Feakins ,&nbsp;B.D.A. Naafs","doi":"10.1016/j.orggeochem.2024.104782","DOIUrl":"10.1016/j.orggeochem.2024.104782","url":null,"abstract":"<div><p>Glycerol dialkyl diethers (GDDs) are membrane lipids and a variation of the more commonly known glycerol dialkyl glycerol tetraethers (GDGTs). GDGTs include both archaeal and bacterial membrane lipids that are both frequently used for paleoclimate reconstruction in a range of terrestrial and aquatic environments. In contrast to GDGTs, GDDs lack one of the terminal glycerol moieties. Although both isoprenoidal (iso) and branched (br) GDDs have been found, this study focuses on isoGDDs. These lipids have been found in a few terrestrial and aquatic environments. However, the origin of isoGDDs is debated and the extent of their distribution across the surface of the Earth is poorly constrained. Based on a few single site studies, previous authors hypothesised that isoGDDs are degradation products of isoGDGTs, but more recent studies that isolated isoGDDs from cultured nitrososphaerota (formerly thaumarchaeota) proposed a biological source through direct archaeal biosynthesis. Here we compiled a global dataset of isoGDD and isoGDGT abundance in environmental samples to thoroughly investigate the distribution of isoGDDs and the correlation with isoGDGTs on a global scale and across a variety of environments (peat, mineral soils, lake sediments, and marine sediments). We find that isoGDDs are present in most samples that we analysed. Their abundance is strongly proportional to isoGDGT abundance (r² = 0.85), dominated by the GDGT-crenarchaeol/GDD-crenarchaeol ratio (r² = 0.94) and supported by individual compound isoGDGT/isoGDD ratios (r² = 0.56–0.94). In addition, the degree of cyclisation of isoGDDs, reflected in the ring index, is positively correlated (r² = 0.84) with that of isoGDGTs across all environments. We conclude that isoGDDs are abundant on the surface of the Earth and predominantly originate from the degradation of isoGDGTs.</p></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"192 ","pages":"Article 104782"},"PeriodicalIF":3.0,"publicationDate":"2024-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0146638024000470/pdfft?md5=ee6d21013c4b667df0c90f4d81708e0b&pid=1-s2.0-S0146638024000470-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140768679","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}