Showing papers in "Organic Geochemistry in 2000"

TL;DR: In this paper, the authors consider the stabilisation of organic materials in soils by the soil matrix is a function of the chemical nature of the soil mineral fraction and the presence of multivalent cations.

TL;DR: In this article, a proxy ratio, Paq, was formulated to reflect the non-emergent aquatic macrophyte input to lake sediments relative to that from the emergent aquatic and terrestrial plants.

TL;DR: In this paper, the authors investigated the role of dissolved organic matter (DOM) in the preservation of organic matter in marine sediments and found that DOM sorption contributes considerably to the accumulation and preservation of OM in soil.

TL;DR: In this article, an investigation of the three-dimensional excitation-emission-matrix (EEM) fluorescence spectra of unconcentrated water samples collected in 1996, 1998 and 1999 at a site particularly propitious for macro-algae development was performed.

TL;DR: The origins, reactions and fates of molecularly-uncharacterized organic matter are relatively obscure, in large part because the rich vein of geochemical information that typically derives from detailed structural and stereochemical analysis is yet to be tapped.

TL;DR: In this article, the authors investigated whether black carbon is additionally stabilised by organo-mineral complexation using benzenecarboxylic acids as molecular markers and found that a large part of black carbon was also found in the heavier fractions, where it was partly embedded within plaques of iron and aluminium oxides on mineral surfaces.

TL;DR: In this paper, a combination of spectroscopic techniques with thermolytic and chemolytic methods will add substantially to the understanding of the nature of refractory soil organic matter.

TL;DR: Hinrichs et al. as mentioned in this paper showed that the methane-consuming archaebacteria in marine sediments are involved in the anaerobic oxidation of methane in sediments from the Eel River Basin, offshore northern California, and further studies of those same sediments and of samples from a methane seep in the Santa Barbara Basin have confirmed and extended those results.

TL;DR: In this paper, a 40 cm peat profile from Bolton Fell Moss, Cumbria, UK showed a varying abundance of the n-C23 homologue down core which appear to be related to vegetation changes, which are presumed to occur as a result of climate variation.

TL;DR: In this paper, a quantitative analysis of separated carboxylic acid fractions of 33 crude oils from the UK, Italy and California, showed that the carboxyl acid fraction is a major factor responsible for the acidity in these oils.

TL;DR: The free lipid compositions of twelve species of Sphagnum were determined by capillary gas chromatography/mass spectrometry as part of a study to identify characteristic lipids for S. palustre in peat bogs.

TL;DR: In this article, the lipid content of the primary organic inputs for each soil were also analysed in order to assess the early diagenetic fate of various compounds present in the soil.

TL;DR: In this paper, a suite of 40 oils and extracts of purported source rocks from the Tarim basin in NW China were studied and compared with Ordovician and Cambrian source rocks.

TL;DR: Weathering profiles developed on organic carbon-rich black shales were studied to examine the loss and degradation of organic matter (OM) during weathering and its role in the geochemical carbon cycle as mentioned in this paper.

TL;DR: A large suite of natural gases from the North West Shelf and Gippsland and Otway Basins in Australia have been characterised chemically and isotopically resulting in the elucidation of two types of gases.

TL;DR: In this article, an analysis of anaerobic sediments at the sulfate reduction-methane production boundary was carried out in the Aleutian deep-sea trench and the results indicated that various archaeal assemblages might be involved in the consumption of methane.

TL;DR: In this paper, it is assumed explicitly that the kinetics of oil destruction and gas formation can be adequately described using a set of parallel first-order reactions, and the mean activation energy for oil and gas generation is about 59 kcal/mol (246.9 kJ/mol), with a frequency factor of about 1014.25 s−1.

TL;DR: In this paper, the distributions of polycyclic aromatic hydrocarbons (PAHs) in sediments of three Upper Triassic to Middle Jurassic sedimentary sequences from the Northern Carnarvon Basin, Australia have been investigated.

TL;DR: In this article, the effect of biodegradation on diamondoid distributions in petroleum has been investigated on a series of crude oils reservoired in two Australian sedimentary basins, the Gippsland Basin and the Carnarvon Basin.

TL;DR: In this article, the authors proposed that the survival of proteins in humic acids is carried out by encapsulation into hydrophobic domains of humic acid and demonstrated that complete hydrolysis of the protein is prevented by the encapsulating acid.

TL;DR: In this paper, the authors measured Δ14C and δ13C values for individual long-chain n-alkanes (C24-33) from Santa Monica Basin sediments and then simulated the results using a three-component mixing model designed to represent the contributions of different sources.

TL;DR: In this article, compound-specific δD values recorded by means of gas chromatography-thermal conversion-isotope ratio mass spectrometry (GC-TC-IRMS) of the biomarker n-alkane (n-tricosane; n-C23) representative of the dominant Sphagnum species in a 40 cm peat profile from Bolton Fell Moss, Cumbria, UK, correlate with vegetation changes in the past >200 years (age depth model based on 210Pb dating).

TL;DR: In this paper, a wide variety of organic lipophilic compounds of biogenic, petrogenic as well as anthropogenic origin were found to indicate the spatial distribution of Elbe river derived organic matter.

TL;DR: A range of well-preserved Neoproterozoic acanthomorph and sphaeromorph acritarchs from the Australian Centralian Superbasin have been individually analysed by combined microscopic and chemical methods as mentioned in this paper.

TL;DR: In this paper, the insoluble, non-hydrolyzable, macromolecular material isolated from a forest soil from Lacadee (south-west France) was examined via a combination of various methods: FTIR spectroscopy, elemental analysis, pyrolysis and high resolution transmission electron microscopy.

TL;DR: In this paper, a combination of microscopic and pyrolytic methods applied on a Cenomanian kerogen was used to demonstrate the crucial role of the mineral matrix both in organic matter preservation during kerogen formation and in kerogen stability once formed.

TL;DR: A mesophilic enrichment culture of sulphate-reducing bacteria isolated from the water phase of a North Sea oil tank using oil from the same tank as sole source of carbon and energy specifically depletes certain C 1 −C 5 alkylbenzenes in crude oil during growth.

TL;DR: In this article, the results from an assessment of the application of a new molecular analytical procedure, 13 CTMAH thermochemolysis, to study the chemical modification of lignin by white-rot and brown-rot fungi were presented.

TL;DR: In this paper, the application of a small angle neutron scattering (SANS) technique for the precise determination of the onset of hydrocarbon transport (primary migration) in shaly source rocks was demonstrated.

TL;DR: The molecular distribution and the carbon-isotopic composition (d 13 C) of n-alkanes extracted from a Lake Baikal core spanning the last 20 kyr of sediment accumulation have been investigated in this article.