Showing papers in "Organic Geochemistry in 1997"

TL;DR: In this article, the organic matter content of sediments is inferred from bulk properties such as elemental compositions, carbon and nitrogen stable isotope ratios, Rock-Eval pyrolysis data, and organic petrography.

TL;DR: In this article, the authors focus on the transport and transformations of land-derived organic matter in the ocean, highlighting recent research on the patterns and processes involved in the degradation of terrestrial organic matter.

TL;DR: In the ocean, nitrogen-rich microorganisms produce and recycle most organic matter in the water column, from which degraded particles rain onto the underlying sea floor and the buried organic matter joins the geological cycle, surfacing again millions of years later as kerogen uplifted in continental rocks as discussed by the authors.

TL;DR: In this paper, the authors compared the maturation of different types of organic matter (kerogen types I, II, II-S and III) in open and anhydrous closed pyrolysis systems.

TL;DR: The authors examines the most recent literature concerning coalification and focuses on the chemistry associated with coalification of certain recognizable plant remains that have been at the center of research activity for the past two decades.

TL;DR: In this article, high-temperature gas chromatography (HT-GC) and HT-GC-mass spectrometers were used to investigate trimethylsilylated total lipid extracts and Curie-point pyrolysis-GC (Py-GC).

TL;DR: Light hydrocarbons (LHs) are catagenic products, formed between ∼ 75 and 140°C, but their mode of origin remains controversial as discussed by the authors, and it is unlikely that the LHs are formed without catalytic support.

TL;DR: In this paper, the thermal alteration of reservoired petroleum upon burial was simulated by closed-system programmed-temperature pyrolysis of produced crude oils of lacustrine, fluviodeltaic, marine clastic and marine carbonate origin using the microscale sealed vessel (MSSV) technique.

TL;DR: The Forensic Environmental Geochemistry (FEG) methodology as mentioned in this paper is a combination of specialized analytical procedures used in standard contamination characterization with methodology developed in organic geochemistry, a combination referred to as forensic environmental geochemistry.

TL;DR: In this paper, seasonal changes in δ13C values for individual lipids from the leaves of several species of tree have been studied in order to provide essential background information for use in future investigations of the isotopic signatures of terrigenous sedimentary organic matter.

TL;DR: In this paper, the upper Devonian Nisku Formation reservoirs of the Brazeau river area of west-central Alberta, Canada, produce oil and sweet and sour gas condensate.

TL;DR: Aliphatic eustigmatophyte algaenans from fresh water green microalgae are likely to be selectively preserved in depositional environments and might ultimately serve as source rock organic matter of marine crude oils.

TL;DR: In this article, a new maturity index was proposed based on the assumption that alkyl-DBT isomers with the methyl substituent in the 4 position are the most thermodynamically stable.

TL;DR: In this article, the environmental occurrence of long-chain mid-chain diols, keto-ols, and mid chain hydroxy fatty acids is reviewed, and the composition of positional isomers of these compounds differs remarkably between cultures of microalgae from the genus Nannochloropsis, and sediments, suggesting that these algae are not the major sources for the compounds to the sediments.

TL;DR: In this paper, the role of bottom water oxygen conditions to organic matter preservation and the differential contribution of bacteria to sedimentary organic matter accumulation and composition was investigated in the Santa Monica Basin.

TL;DR: Several diterpenoids of the abietane, pimarane and phyllocladane type have been identified in the organic solvent extracts of Lower Oligocene clay sediments (Haselbach strata, Saxony, Germany) as mentioned in this paper.

TL;DR: A series of oxic and anoxic incubations examined lipid degradation in two marine phytoplankton, the diatom Thalassiosira weissflogii and the coccoid cyanobacterium Synechococcus sp, using flow-through systems without macrozooplankton grazers as mentioned in this paper.

TL;DR: In this paper, a detailed study was carried out to compare the geochemistry of the crude oil in the Lower Cretaceous Toro sandstone reservoir in the Iagifu-7X well with oil trapped in fluid inclusions in this sandstone in the Papuan Fold Belt.

TL;DR: In this paper, a set of oxidized and unoxidized sediment intervals from the f-turbidite identified in two piston cores from the Madeira Abyssal Plain (MAP) was analyzed for calcium carbonate, total organic carbon (TOC), total nitrogen (TN), stable carbon composition of TOC (δ13C toc ), total hydrolyzable amino acids (THAA), total neutral sugars (TSUG), lignin phenols (LIG), two different lipid biomarkers of marine phytoplankton origin and vascular plantwax

TL;DR: In this paper, a 2 m core (Rheinberger heide) covering the entire deposition of the Permian Kupferschiefer (Lower Rhine Basin, northwest Germany) was used to investigate changes in depositional conditions.

TL;DR: In this article, a quantitative study of pyrrolic nitrogen compounds was conducted on a series of marine carbonate petroleum source rock extracts taken from the Upper Devonian Duvernay Formation in the central Alberta portion of the Western Canada Sedimentary Basin.

TL;DR: In this article, the exact concentrations of various bio-and geohopanoids have been determined in a 24 cm long core from anoxic recent sediments of Priest Pot, a small highly productive lake in the English Lake District.

TL;DR: In this paper, thermal maturation of organic matter near a well-dated intrusion in the DSDP 41-368 hole near Cape Verde Rise, eastern Atlantic, and near some other intrusions from the U.K., U.S. and east Greenland.

TL;DR: In this article, organic matter in speleothem calcite, marine carbonate cements and aragonitic coral skeletons was studied to determine its location, molecular structure, functionality and effect on mineral growth.

TL;DR: In this paper, a maize growing field was analyzed for molecular structure by gas chromatography-mass spectrometry, for 13 C/12 C ratios by isotope ratio mass spectrometer, and for 14 C age by accelerator mass analyzer.

TL;DR: Two case studies demonstrating the utility of isotopic analyses for tracing the history of human behavior are presented and the challenge will be to broaden the techniques and samples available for analysis to proxy materials not directly associated with skeletal remains so that an even older human record can be read.

TL;DR: Time-related changes in the Proterozoic sedimentary isotopic record of organic carbon and carbonates are consistent with the following: (1) an increase in the oxidation state of the environment, (2) a transition towards microbial populations dominated by producers and utilizers of O 2 and SO 4 2−, and (3) a relatively minor increase in organic δ 13 C during postdepositional thermal alteration as discussed by the authors.

TL;DR: In this article, the authors used gas chromatography and mass spectrometry to identify long-chain unsaturated alkenones derived from prymnesiophytes and fatty acids derived from diatoms and dinoflagellates.

TL;DR: In this article, the authors performed simultaneous mass spectral detection and stable carbon isotope analysis on individual indigenous n -alkanes isolated from single C 4 and C 3 plant species and on a series of aliphatic and polycyclic aromatic hydrocarbons (PAH) produced from the combustion of these same biomass materials.

TL;DR: The fate and transport of terrestrial organic matter across the continental margin in the Gulf of Mexico was studied in 1992 and 1993 using chemical biomarkers as discussed by the authors, and the dominant mechanism for transport of terrestrially-derived POC and HMW DOC across the shelf and slope was hypothesized to be advection of riverine and estuarine discharges through benthic nepheloid layers.