bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sedimentology and its applications within the UK opencast coal mining industry
Authors: Jones Neil S. , Guion Paul D. , Fulton Iain M. 
Published: April 2008

Abstract
The opencast coal industry seeks to identify and extract near-surface coal reserves. Within the UK Pennine Basin, most coal deposits suitable for opencast exploitation range from middle Westphalian A to lower Westphalian C in age. These deposits dominantly accumulated in an upper delta plain setting in which subsidence rates and depositional setting formed the primary controls on the initial distribution, thickness and quality of coal reserves. Hence an appreciation and analysis of the sedimentary setting and controls on sedimentation are important in the delineation of potential areas of thick, persistent coals.

The calculations of
in situ
coal reserves and coal to overburden ratios are important objectives during exploration for prospective opencast coal sites. Coal reserves are detrimentally affected by early, depositionally related factors such as as wash-outs, seam splits, channel bank collapse and compaction faults. The thickness and type of interseam sedimentary rock (overburden) is directly related to the original despositional environment and the nature of the overburden can change substantially across the working area of an opencast site, reflecting sedimentary facies variations. The various sedimentary facies have unique characteristics and adversely influence mining in a variety of ways, including highwall stability problems, seam gradient changes, groundwater problems, interseam interval variations and facies-specific discontinuities.

Many of these problems are related to the presence of palaeochannels. Palaeochannels occur at different scales and contain a variety of fills, and their identification is an important aspect of site exploration. Sedimentary facies mapping, incorporating facies analysis, the construction of isopach maps and palaeocurrent studies can play an important part in an opencast exploration programme. Facies maps have many applications which may be invaluable in site planning, including the delineation of areas of sedimentary disturbance, improved understanding of seam thickness and quality variations, and changes in the interseam strata.
An update on British Tonsteins
Authors: Spears D. A. , Lyons P. C. 
Published: April 2008

Abstract

Tonsteins are thin mudstone beds composed of kaolinite that formed from the alteration of volcanic ash in coal-forming environments. In the Coal Measures of Britain, tonsteins have been recognized as volcanic in origin based on bedform, volcanic textures, field relationships with other volcanics, distinctive volcanic minerals and an igneous geochemistry. The sharp contacts, together with a contrasting composition with adjacent sediments and lateral continuity, are diagnostic of an altered air-fall volcanic ash. Passage into less altered volcanics and into a K-bentonite have both been shown in Britain. A more direct determination of volcanic origin is possible from the identification of volcanic minerals, whole-rock geochemistry and analyses of silicate melt inclusions in volcanic minerals such as
β
quartz. Once a volcanic origin is established the stratigraphic value of a tonstein is enhanced. Immobile trace elements in tonsteins also provide information on the tectono-magmatic setting of the parent volcano. Two tonstein groups are identified in the Coal Measures of Britain, one formed from basic (basaltic) ash of local origin and the other from acid (rhyolite or rhyodacite) ash, probably associated with distant Plinean or ultraplinean eruptions at a destructive plate margin to the south or southeast.
Coals of Greece: distribution, quality and reserves
Authors: Koukouzas C. , Koukouzas N. 
Published: April 2008

Abstract

Greek coals occur in a number of sedimentary basins and range in age from Eocene to Quaternary. The petrographic data indicate a wide variation in petrographic and chemical composition. The rank ranges from the transition zone peat-lignite to subbituminous. There are no deposits of hard coal in the country. Lignite constitutes the most abundant type of coal in Greece and the most important of the Greek lignite deposits formed during the Pliocene and Pleistocene in shallow lakes and marshes of closed intramontaine basins (Ptolemais, Florina, Drama in Macedonia, northern Greece and Megalopolis in Peloponnesus, southern Greece). The proved lignite reserves are currently estimated at 6750 Mt, excluding the 4300 Mm
3
of ‘Phillipi’ peat in Macedonia. There, 58% (about 3900 Mt) is considered to be economically recoverable. The probable and possible reserves are estimated to be of the order of 4000 Mt. The Kozane-Ptolemais-Amynteo-Florina basins in Macedonia contain most (about 64%) of the nation’s coal resources. These lignites, which are all already being exploited, have a very low calorific value (at Ptolemais-Amynteo, 1400 kcal kg
−1
; at Megalopolis, 900 kcal kg
−1
) and high ash and low sulphur contents. The lignite production for 1992 was over 54 Mt. the greatest centres of lignite production are in Macedonia, at the opencast mines of Ptolemais and Amynteo, and in Peloponnesus, at the opencast mine of Megalopolis. The vast majority (98%) of the extracted lignite is used for electricity generation and feeds power plants which have a total capacity of 4533 MW. The lignite-based power plants account for more than 720f the total electricity generation of the country. Today, through detailed geological exploration and evaluation, efforts are being made to locate and develop other lignite deposits throughout Greece.
European Community energy policy: import dependency and the ineffectual consensus
Authors: Wright Philip 
Published: April 2008

Abstract
The lack of an effective European Community (EC) energy policy is discussed in the context of the different degrees and kinds of energy import dependency faced by the different member states. The way in which these contrasting energy economies have impinged on the evolution of EC energy policy, rendering it largely ineffectual, is then explored over the period 1974 to 1992.
The general theme is illustrated by focusing on the evolution of EC policy towards the coal industry, identifying how it has been impotent in the face of national government policies and perverse in terms of its recent outcomes. This argument is supported by data comparing the productivity performances of the different EC coal industries.
Unusual enrichment of U, Mo and V in an Upper Cretaceous coal seam, Hungary
Authors: Tomschey Otto 
Published: April 2008

Abstract
The Late Cretaceous coal basin of Ajka lies in the Bakony Mountains, Transdanubia, Hungary, above Triassic-Jurassic dolomites-limestones and/or Upper Cretaceous calcareous marly sediments. The concentrations of U, Mo and V are unusually high (U = 80 ppm, Mo = 138 ppm and V = 600 ppm on average in ash). Analyses were carried out to determine the trace metal concentrations in the various solid phases within the coal rock and the results compared with the U, Mo and V contents of fly ash from the mine-mouth thermal power plant.
Origin and distribution of sulphur in the Neogene Beypazari Lignite Basin, Central Anatolia, Turkey
Authors: Whateley M. K. G. , Tuncali E. 
Published: April 2008

Abstract
During the Miocene a number of fault-bounded basins developed in Central Anatolia, Turkey. These basins were filled initially with coarse clastic material. Upward fining of the clastics during basin-fill, with an increase in the amount of clay and carbon content, led to the development of relatively shallow limnic basins in which extensive peat deposits accumulated. One such basin at Çayirhan, near Beyparazi, contains thick laterally extensive lignite seams. These lignites are characterized by their high sulphur content (up to 8.20n an air-dried basis). It is suggested that hydrothermal processes are responsible for the increased sulphur contents of the Çayirhan lignites, resulting from sulphate and sulphide precipitation. The mineral matter contains ubiquitous zeolites. The presence of heulandite in the first seam and analcime in the second seam may be a result of depth-temperature control on the distribution of zeolites in the lignite; but these differences are more probably the result of variations in the chemistry of the circulating fluid. Study of the sulphur content reveals three types of sulphur distribution, namely, vertical variation within individual seams, variation between seams and lateral variation across the basin. The first two are related to variations in the chemistry of the mineral matter in the lignite, and the last is probably related to structural/topographic control of the mire at the time of formation.
Fossil indicators of nutrient levels. 1: Eutrophication and climate change
Authors: Brasier M. D. 
Published: April 2008

Abstract

Both phosphorus and nitrogen are elements essential to life. Availability of these biolimiting nutrients therefore exerts a major control on the carbon cycle through ocean productivity, bringing about changes in ocean-atmosphere chemistry and climate. This review begins with a brief account of the biological importance of phosphorus and nitrate to the cell, and introduces current terminology relating to the interlinked carbon-nutrient cycles in the oceans. Nitrate-limited, eutrophic ecosystems are associated with modern upwelling zones, characterized by high rates of delivery of new phosphorus, high rates of new primary production and export production. Fossil indicators include high accumulation rates of biogenic silica, apatite, baryte and organic matter, plus non-spinose, smaller planktonic foraminifera. Examples from biomineral chemistry include indications of high Ba/Ca, high Cd/Ca and increased differences between δ
13
C in planktonic and benthic foraminiferal test calcite. Such eutrophic indicators are shown to have peaked during glacial phases in the Quaternary, supporting a model in which Milankovitch-related reductions in solar isolation influenced the availability of nutrients, increasing primary productivity and lowering the levels of atmospheric carbon dioxide.
Modelling of vapour-liquid-liquid equilibria of CO
2
-crude oil mixtures
Authors: Jørgensen Marianne , Stenby Erling H. 
Published: April 2008

Abstract

At temperatures close to the critical temperature of carbon dioxide, some crude oils form three phases when mixed with CO
2
. The objective of this work was to investigate whether the three-phase behaviour of CO
2
-crude oil mixtures can be predicted with the Soave-Redlich-Kwong equation of state. In the description of the C
7+
-fraction, a previously described characterization method was applied. In this characterization procedure, the critical properties and the acentric factor of single carbon number groups within the plus fraction are estimated on the basis of measurable physical properties. By comparison of experimental and calculated data, it is shown that no, or very little tuning of the EOS parameters is necessary to obtain representative predictions of three-phase regions. In addition it is demonstrated how too severe tuning leads to very erroneous results in the simulation of phase diagrams. Finally, it is shown how the described method fails to predict the three-phase region of a very heavy oil with a small three-phase region at the given temperature.
A new approach to oil rim development
Authors: Zakirov S. N. , Shandrygin A. N. , Romanov A. S. 
Published: April 2008

Abstract
Recovery factors for oil rims are usually low. This paper deals with the possibility of improving the recovery efficiency by means of various combinations of water and/or gas injection. These cases are evaluated both experimentally and by mathematical simulation. The best results are obtained by simultaneous injection of water and gas. The recovery depends on the water-gas injection ratio.
Commercial polymer injection in the Courtenay Field, 1993 update
Authors: Putz A. , Pedron B. , Bazin B. 
Published: April 2008

Abstract

The Courtenay reservoir has an elongated shape and lies at a depth of 600 m. With an oil viscosity of 40 cP, fresh formation water and a temperature of 30°C, conditions are favourable for polymer injection. In July 1989 a project was started with 18 producers forming three adjacent polygons (pore volume 640 000 m
3
) and four injection wells. A 900 ppm polyacrylamide solution diluted with field water was injected at a total rate of 380 m
3
/day. With 84% of pore volume injected, the project has now reached a mature stage and the polymer concentration is being tapered off. The total production of oil confirms original expectations, and the operation is profitable.

Oil bank build-up has been observed in 14 production wells. An additional 265 000 bbl or 6.6% of pore volume has been already recovered in addition to the extrapolated primary recovery, for a polymer/oil ratio of 1.16 kg/bbl. With a total cost of $12/bbl the project is clearly profitable.
Simulation of the project performance with a 3D, three-phase simulator including polymer and tracer options resulted in a good match of total oil production. However, for most wells the actual amount of polymer produced is lagging behind the values predicted by the simulator.
Detailed analysis of the polymer produced by well CY 55 confirmed that no degradation had occured.
Devonian precessional and other signatures for establishing a Givetian timescale
Authors: House Michael R. 
Published: April 2008

Abstract
Palaeozoic radiometric dates are so isolated and crude as to offer little numerical precision in stratigraphy. In a Givetian sequence of pelagic micrites in the Montagne Noire of southern France there is a succession of small-scale microrhythms which appear to represent precessional signatures. Correlations can be made with other sections in the Tafilalt of southern Morocco and, for the late Givetian, in the Marble Cliff Beds of north Cornwall. Now that the IUGS has approved boundaries defining the upper and lower limits of the Givetian it is possible to estimate the number of putative precessional signatures for the whole Givetian and, using the calculation of periods for these in the Devonian, to estimate the duration of the Givetian and its conodont zones independantly from radiometric dates.
Graphical correlation techniques are used to establish a time framework for the Givetian and this is used to estimate the duration of zones in relation to the preliminary precessional scale, and hence to estimate their duration in real time. Biological changes and sedimentary events can similarly be constrained against a scale for the Givetian. It is suggested that such techniques, using a stage for a base, is likely to be useful long before continuous orbital forcing timescales (OFT) can be established. It would be a start in eliminating present crude estimates of the length of stages based on the false presumption that zones within them are of equal duration. Given boundaries, defined internationally by IUGS at Global Stratotype Section and Points, such OFT scales would enable events and zonal durations to be given in relation to OFT graphic composite scales and on the basis of estimated precessional signatures.
Cyclostratigraphy, Quo Vadis?
Authors: Fischer Alfred G. 
Published: April 2008

Abstract

Climatic oscillations forced by orbital variations left their imprint not only on Pleistocene ice regimes, as postulated by Croll (1875,
Climate and Time in their Geological Relations
, Appleton, New York) and by Milankovitch (1941,
Belgrade, Serbian Academy of Science
,
133
), but also on the sedimentary record as postulated by Gilbert (1895,
Journal of Geology
,
93
, 515–533), and not only in glacial times but also, and particularly sharply, in times of greenhouse climates. The amenable facies are those characterized by relatively continuous sedimentation, though in carbonate platforms interruptions constitute the Milankovitch signal. The recording mechanisms include variations in biogenic components and biotic activity, and direct expressions of physical and chemical sedimentation.

So far, cyclostratigraphy has largely remained a demonstration of principle. Applications to geochronology are in their beginnings. The chronological refinement promised by cyclostratigraphy demands quantities of stratigraphic data orders of magnitude beyond those of conventional stratigraphy. Progress in application will therefore depend on combining automated scanning devices (well logs, core and sample logging techniques of various sorts) capable of providing simple variation graphs of long sedimentary sequences, with detailed paleontological and magnetostratigraphic studies. The existence of the cycle hierarchy will provide some protection against chronological errors induced by cryptic gaps in the record, as will the reproduceability of results in distant sequences and different facies, and the possible finger-printing of individual cycles by magnetic character.
Fractionation of pyrrolic nitrogen compounds in petroleum during migration: derivation of migration-related geochemical parameters
Authors: Li Maowen , Larter S. R. , Stoddart D. , Bjorøy M. 
Published: April 2008

Abstract
Analysis of a range of crude oils and source rocks appears to indicate that primary and secondary oil migration has a strong impact on the distribution of pyrrolic nitrogen compounds in reservoired petroleum. The migration effects controlling the composition of pyrrolic nitrogen compounds recognized tentatively in this study include (a) the relative enrichments of alkyl carbazoles to alkylbenzocarbazoles, (b) nitrogen-shielded isomers to nitrogen-exposed isomers, and (c) higher homologues to the lower homologous species. A suite of molecular migration parameters based on chemical compositions of pyrrolic nitrogen compounds in crude oils have been proposed. If substantiated in more case history studies, these parameters are potentially useful in petroleum population mapping.
Detailed geological studies of hydrothermal fields in the North Atlantic
Authors: Krasnov S. G. , Cherkashev G. A. , Stepanova T. V. , Batuyev B. N. , Krotov A. G. , Malin B. V. , Maslov M. N. , Markov V. F. , Poroshina I. M. , Samovarov M. S. , Ashadze A. M. , Lazareva L. I. , Ermolayev I. K. 
Published: April 2008

Abstract
Sidescan sonar and TV/photo surveys, TV-controlled sulphide grab sampling and sediment sampling have been carried out at the TAG and MARK hydrothermal fields of the Mid-Atlantic Ridge during research cruises of the Sevmorgeologija Association, St Petersburg. Detailed mapping of the MARK field (23°N) allowed contouring of the massive sulphide bodies. The largest of them are Cu-enriched and the smallest zincenriched. Sulphides of the TAG field (26°N) active mound appear to be Cu-rich in its central and Zn-rich in its marginal parts. Sampling of the inactive Mir hydrothermal mound of the TAG field revealed an enrichment in Cu in its northern part and an abundance of silica in the south. This mound and especially the north hydrothermal zone, both presently inactive, determined the metal distribution in TAG sediments during the last 10 000–13 000 years. Extensive Cu-rich sulphide deposits were also discovered and sampled near 14°45′N. The dominance of Cu over Zn in mature Mid-Atlantic Ridge hydrothermal deposits, arising at late stages of their formation, can probably be explained by dominant leaching of Cu from basalts at advanced stages of development of the hydrothermal systems and/or by increasing the efficiency of Cu sulphide deposition in the course of formation of the ore body.
Preliminary observations on biological communities at shallow hydrothermal vents in the Aegean Sea
Authors: Dando P. R. , Hughes J. A. , Thiermann F. 
Published: April 2008

Abstract

Hydrothermal vents, at depths varying from the littoral zone to water depths of 115 m, have been explored around the islands of Milos and Santorini in the Hellenic Volcanic Arc. The biota were surveyed by scuba divers and with a remote operated vehicle as well as by soft-bottom sampling with grabs and corers. No species specific to hydrothermal areas were found at any of the sites investigated. Animals in the immediate vicinity of the vents belonged to opportunistic species, such as the polychaetes
Capitella capitata, Microspio
sp. and
Spio decoratus
. The nassariid gastropod
Cyclope neritea
was the dominant macrofaunal species found in the bacterial mat areas at Milos which overlay hot brine seeps. At all rocky hydrothermal sites deeper than 35 m water depth the echiuran
Boniellia
cf.
viridis
was observed. Around the periphery of the seeps the meiofaunal community was dominated by the nematode
Onchlaimus camplyoceroides
. Few nematodes were found in the centre of the hydrothermal brine areas. At Santorini the bacteria at the venting sites were dominated by iron bacteria, whereas at Milos large globular sulphur bacteria,
Achromatium volutans
, covered the hydrothermal brine seeps. Unlike deep-sea vents, little of the biomass production was due to symbiotic associations between animals and chemoautolithotrophic bacteria, although a few stilbotnematine nematodes were found at the periphery of the brine seeps at Milos. Macrofaunal biomass reached a maximum of 80 g m
−2
around the vents, compared with ≥c 500 g m
−2
at hydrothermal vents elsewhere. Much of the bacterial biomass appeared to be exported from the sites.
Lipid characteristics of hydrothermal vent organisms from 9°N, East Pacific Rise
Authors: Rieley Gareth , van Dover Cindy L. , Hedrick David B. , White David C. , Eglinton Geoffrey 
Published: April 2008

Abstract

Lipid compositions are reported for three distinctive deep-sea hydrothermal vent invertebrate species collected around 9°N East Pacific Rise:
Riftia pachyptila
Jones, a vestimentiferan tubeworm;
Bathymodiolus thermophilus
Kenk and Wilson, a mussel; and
Halice hesmonectes
Martin
et al.
, an amphipod crustacean. The lipid compositions of all these organisms were dominated by components characteristic of diets based on bacteria, with only very minor contributions from carbon derived from the oceanic photic zone. In all the organisms studied, large abundances of n-7 fatty acids, polyunsaturated fatty acids with unsaturations separated by more than one methylene bond, and sterol distributions dominated by cholesterol were observed. Branched fatty acids were generally of low abundance, whereas polyunsaturated fatty acids separated by single methylene groups were either absent, as in the case of
R. pachyptila
, or in very low abundance, as in the case of
B. thermophilus
and
H. hesmoncetes
. Monounsaturated fatty acids were the most abundant component of
R. pachyptila
lipids, whereas non-methylene interrupted fatty acids were particularly abundant in the lipids of
B. thermophilus
(up to 450f total fatty acids). The lipids of
H. hesmonectes
were dominated by storage lipids (e.g. wax esters). Stable carbon isotope analyses of individual sterols from the organisms examined allow specific sources to be proposed for these biochemicals. The δ
13
C values of sterols from
R. pachyptila
were consistent with
de novo
biosynthesis, whereas that of cholesterol from
B. thermophilus
corresponded to that from marine phytoplankton. The δ
13
C values of sterols from
H. hesmonectes
fell into two different groups and suggest that at least two distinct sources of sterols are available to these crustacea in the vent ecosystem, one of which derives from phytoplankton. Overall, the combination of the interpretation of lipid structure and distribution with compound specific isotope analyses can lead to valuable insights into trophic relationships within the deep-sea hydrothermal ecosystem.