Total organic carbon, delta13C, biomarker, gas compilations and hopanoids analysis from IODP Sites 307-U1317 and 307-U1318

During the Integrated Ocean Drilling Program (IODP) Expedition 307 for the first time a cold-water coral carbonate mound was drilled down through its base into the underlying sediments. In the current study, sample material from within and below Challenger Mound, located in the Belgica carbonate mound province in the Porcupine Basin offshore Ireland, was investigated for its distribution of microbial communities and gas composition using biogeochemical and geochemical approaches to elucidate the question on the initiation of carbonate mounds. Past and living microbial populations are lower in the mound section compared to the underlying sediments or sediments of an upslope reference site. A reason for this might be a reduced substrate feedstock, reflected by low total organic carbon (TOC) contents, in the once coral dominated mound sequence. In contrast, in the reference site a lithostratigraphic sequence with comparatively high TOC contents shows higher abundances of both past and present microbial communities, indicating favourable living conditions from time of sedimentation until today. Composition and isotopic values of gases below the mound base seem to point to a mixed gas of biogenic and thermogenic origin with a higher proportion of biogenic gas. Oil-derived hydrocarbons were not detected at the mound site. This suggests that at least in the investigated part of the mound base the upward flow of fossil hydrocarbons, being one hypothesis for the initiation of the formation of carbonate mounds, seems to be only of minor significance.

(Table 1) Mean grain sizes and standard deviations of gas hydrate samples

Methane hydrates are present in marine seep systems and occur within the gas hydrate stability zone. Very little is known about their crystallite sizes and size distributions because they are notoriously difficult to measure. Crystal size distributions are usually considered as one of the key petrophysical parameters because they influence mechanical properties and possible compositional changes, which may occur with changing environmental conditions. Variations in grain size are relevant for gas substitution in natural hydrates by replacing CH4 with CO2 for the purpose of carbon dioxide sequestration. Here we show that crystallite sizes of gas hydrates from some locations in the Indian Ocean, Gulf of Mexico and Black Sea are in the range of 200-400 µm; larger values were obtained for deeper-buried samples from ODP Leg 204. The crystallite sizes show generally a log-normal distribution and appear to vary sometimes rapidly with location.

Mexico's oil and gas policy : an analysis /

Prepared by G. J. Pagliano and others.

Proposed standard for radon-222 emissions from licensed uranium mill tailings : draft economic analysis /

"40 CFR Part 61, national emission standards for hazardous air pollutants."

Gas and fuel analysis for engineers; a compend for those interested in the economical application of fuel, prepared especially for the use of students at the Massachusetts institute of technology,

"References" at the end of some of the chapters.

Calculations and supporting material for the preliminary analysis of the bumper standard.

Mode of access: Internet.

The purification and gas chromatographic analysis of helium /

"Issued June 30, 1961."

Report on available standard samples and related materials for spectrochemical analysis, 1960.

Mode of access: Internet.

Final report : Air quality analysis of the Southern California Bight in relation to potential impact of offshore oil and gas development /

Mode of access: Internet.

Standard methods of milk analysis, bacteriological and chemical.

Bibliography at end of each chapter except three.

Report on standard samples for spectographic analysis,

Mode of access: Internet.

Standard method of milk analysis, bacteriological and chemical.

Bibliography: p. 24-25.

Standard methods of chemical analysis.

Previous editions edited by W. W. Scott.