bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mineralogy and microanalysis in the determination of cause of impact damage to spacecraft surfaces
Authors: Graham G. A. , Kearsley A. T. , Drolshagen G. , McDonnell J. A. M. , Wright I. P. , Grady M. M. 
Published: April 2008

Abstract

Cosmic dust grains are the abundant, fine-grained end-member of a range of extraterrestrial materials travelling through space. These particles can impact orbiting space vehicles (e.g. satellites and the International Space Station) at velocities ranging from 10 to 72 km s
−1
. Impact damage resulting from such a collision could potentially disable or limit the operational use of a spacecraft. There is great commercial interest from the satellite companies and space agencies to understand the nature and proportion of impacts that are caused by cosmic dust particles to assist in risk management studies and for protective shielding optimization. The successful recovery of any surface that has been exposed to the near-Earth environment offers an excellent opportunity to search for micrometre-scaled impact features and the associated projectile residues using scanning electron microscopy and X-ray microanalysis.
Assessing element variability in small soil samples taken during forensic investigation
Authors: Jarvis Kym E. , Wilson H. Elizabeth , James Sarah L. 
Published: April 2008

Abstract
Inductively coupled plasma analytical techniques are widely used in forensic geochemistry because they can provide concentration data for a wide range of major and trace elements relatively rapidly and at reasonable cost. A pilot study was undertaken to identify the relative importance of uncertainty resulting from instrumental measurement sources and that due to the procedures used to prepare the samples initially. Three soils with a range of major and trace element concentrations were collected to permit an evaluation of uncertainty. A reference sample of demonstrated homogeneity was also prepared and analysed. Samples were prepared in replicate (five preparations) of each, and assessment made of uncertainty in the instrumental measurement alone and for replicated preparations of the same material. Small sample sizes (0.05g) were used to mimic the situation common in forensic investigation. Results show that, while instrumental variability may be an important factor during measurement, between-sample variation has a dominant effect on uncertainty in the final result. It is clear that, without replicated measurement and preparation, the uncertainty of the measured data is unknown. Thus, critical samples, on which a case might depend, must be analysed in a way that defines clearly that uncertainty.
Isotope and trace element analysis of human teeth and bones for forensic purposes
Authors: Pye Kenneth 
Published: April 2008

Abstract

Isotopic and elemental concentration data can be extremely useful in the identification of human remains. Archaeological, ecological and forensic investigations to date have primarily made use of
87
Sr/
86
Sr,
143
Nd/
144
Nd,
18
O/
16
O and trace element data obtained from analysis of carbonate-hydroxyapatite in bones and teeth, and/or
12
C/
13
C,
14
N/
15
N,
18
O/
16
O and
35
S/
37
S ratios in bone collagen. However, a wide range of other chemical parameters are potentially useful for intersample comparison and environmental characterization, and increasing attention is being given to hair, nail and skin tissues, which provide dietary and environmental information over shorter time periods than bones and teeth. This paper reviews some of the principles which underlie such work and the current position with regard to modern forensic applications.
Soil as significant evidence in a sexual assault/attempted homicide case
Authors: Stam Marianne 
Published: April 2008

Abstract
In October 1999, a woman and her two small children were assaulted by a male acquaintance on the banks of the New River in the Imperial Valley desert region of California, USA, approximately 160 km east of San Diego. The area includes a number of agricultural fields, old lake deposits, sand dunes and the Salton Sea, a large saline inland sea. The victims escaped from the suspect and hid for 30 h in the New River, thus diminishing the possibility of obtaining physiological fluids as evidence for DNA testing. Wet and soiled clothing and shoes were collected from a suspect’s residence within hours of the assault being reported. The suspect denied any contact with the victims or with the crime scene. Analyses of the soil on the suspect’s clothing and shoes, and of crime scene soil using microscopical methods and X-ray diffraction, indicated that the soil from the crime scene and soil on the suspect’s clothing and shoes were similar. Predominant wind directions and observations of the soil distribution at the crime scene added significance to the observed similarities between the soil samples at the crime scene and the soil on the suspect’s clothing and shoes.
The case for underground CO
2
sequestration in northern Europe
Authors: Chadwick R. A. , Holloway S. , Brook M. S. , Kirby G. A. 
Published: April 2008

Abstract

In northern Europe numerous industrial point sources of CO
2
surround the North Sea Basin, which contains a number of viable underground sequestration opportunities. These include injection into depleted oil and gas fields and into major regional aquifers; the latter probably offering the greatest ultimate storage potential. At the Sleipner gas field, CO
2
is being injected into the Utsira Sand, a large saline aquifer. More than 6 Mt of CO
2
have currently been injected, with a projected final target of about 20 Mt. Time-lapse seismic reflection data are being used to monitor the operation and have provided clear images of the CO
2
plume and its development with time. Moreover, CO
2
volumetrics derived from the seismic data are consistent with the well injection figures. In conjunction with reservoir simulation studies, time-lapse seismic monitoring seems, therefore, to offer an effective means of predicting the future growth, migration and dispersion of the CO
2
plume. Another important aquifer, the Bunter Sandstone, stretches from Britain to Poland. In the UK sector alone, the pore volume in structural closures is equivalent to about 350 years’ worth of current CO
2
emissions from UK power generation. Industrial CO
2
sources in northern Europe are well placed to exploit these major subsurface reservoirs and European countries are technically very well equipped to use and develop this emerging technology.
Reservoir geology of the Utsira Formation at the first industrial-scale underground CO
2
storage site (Sleipner area, North Sea)
Authors: Zweigel Peter , Arts Rob , Lothe Ane E. , Lindeberg Erik B. G. 
Published: April 2008

Abstract

At the Sleipner fields in the North Sea, CO
2
is being injected into sands of the Miocene-Pliocene Utsira Formation, which is overlain by thick Pliocene shales. The highly porous (35%–40%) and extremely permeable (approximately 2 D) Utsira sands are organized into approximately 30 m thick packages. These packages are separated by thin (predominantly 1 m thick), low-permeability shale layers, which are assumed to contain potential fluid pathways of erosive or deformational origin. A 6.5 m thick shale layer close to the top of the sands separates an eastward thickening sand wedge from the main sand package below. Migration simulations indicate that the migration pattern of CO
2
below the shale layer would differ strongly from that within the sand wedge above. Time-lapse seismic data acquired prior to the start, and after three years, of injection confirmed a reservoir model based on these findings and showed that the thin shale layers act as temporary barriers and that the 6.5 m thick shale layer does not fully inhibit upward migration of CO
2
.
Acid-gas injection in the Alberta basin, Canada: a CO
2
-storage experience
Authors: Bachu Stefan , Gunter William D. 
Published: April 2008

Abstract

Over the past decade, oil and gas producers in the Alberta basin have been faced with a growing challenge to reduce atmospheric emissions of hydrogen sulphide (H
2
S) that is produced from ‘sour’ hydrocarbon pools. Since surface desulphurization is uneconomic, increasingly operators are turning to acid-gas disposal by injection into deep geological formations. Acid gas, a mixture of hydrogen sulphide and carbon dioxide (H
2
S and CO
2
), is the by-product of ‘sweetening’ sour hydrocarbons. Although the purpose of the acid-gas injection operations is to dispose of H
2
S, significant quantities of CO
2
are also being injected because it is uneconomical to separate the two gases. The acid-gas injection operations in the Alberta basin represent an analogue to geological sequestration of CO
2
. Large-scale injection of CO
2
into depleted oil and gas reservoirs and into deep saline aquifers is one of the most promising methods of geological sequestration of CO
2
, and in this respect it is no different from acid-gas disposal operations. However, before implementation of greenhouse-gas geological sequestration, a series of questions need to be addressed; the most important ones relate to the short- and long-term fate of the injected CO
2
. Thus, the study of the acid-gas injection operations in Alberta provides the opportunity to learn about the safety of these operations and about the fate of the injected gases, and represents a unique opportunity to investigate the feasibility of CO
2
geological sequestration.
Relationship between diatremes, dykes, sills, laccoliths, intrusive-extrusive domes, lava flows, and tephra deposits with unconsolidated water-saturated sediments in the late Variscan intermontane Saar-Nahe Basin, SW Germany
Authors: Lorenz Volker , Haneke Jost 
Published: April 2008

Abstract
The late Varican intermontane Saar-Nahe Basin underwent an intensive episode of synsedimentary intra-basinal magmatism, with magmas ranging from tholeiitic basalts to rhyolites. Volcanism began late in the sedimentary history of the basin, after accumulation of about 5000–5500 m of continental sediments. Basic to silicic maar-diatremes formed mostly on hydraulically active faults or fault intersections. Basic to intermediate sills were emplaced at depths between about 2500 m and almost the original surface. Some sills inflated considerably in thickness. Silicic laccoliths intruded in the same depth range. Ongoing volume inflation of some laccoliths led to huge intrusive-extrusive domes, rock falls and probably block-and-ash flows and even to extensive thick lava extrusions. Some domes are composite or show evidence for magma mingling. In the Baumholder-Idar-Oberstein area, lava flows reach a cumulative thickness of 800–1000 m. Outside this thick lava pile, flows are concentrated in several thinner series. Basic to intermediate lava flows were frequently inflated to a thickness of up to 40 metres and were emplaced like thick flood basalts. Silicic tephra deposits are widespread and mostly phreatomagmatic in origin.
The specific formation of maar-diatremes, sills, laccoliths and most tephra deposits is related to the uppermost 1500 to about 2500 m of the continental sediments of the basin fill. During volcanism and subvolcanism, these sediments were largely unconsolidated and water-saturated, and thus this soft sediment environment influenced very specifically the emplacement of the magmas in the basin. Inflation of laccoliths in this environment caused slumping and washing away of the updomed unconsolidated roof sediments. Consequently, the effective initial overburden decreased with time by this particular process of unroofing, and, upon further inflation, larger inflating intrusive domes became extrusive.
Formation of saucer-shaped sills
Authors: Malthe-Sørenssen A. , Planke S. , Svensen H. , Jamtveit B. 
Published: April 2008

Abstract
We have developed a coupled model for sill emplacement in sedimentary basins. The intruded sedimentary strata are approximated as an elastic material modelled using a discrete element method. A non-viscous fluid is used to approximate the intruding magmatic sill. The model has been used to study quasi-static sill emplacement in simple basin geometries. The simulations show that saucer-shaped sill complexes are formed in the simplest basin configurations defined as having homogeneous infill and initial isotropic stress conditions. Anisotropic stress fields are formed around the sill tips during the emplacement due to uplift of the overburden. The introduction of this stress asymmetry leads to the formation of transgressive sill segments when the length of the horizontal segment exceeds two to three times the overburden thickness. New field and seismic observations corroborate the results obtained from the modelling. Recent fieldwork in undeformed parts of the Karoo Basin, South Africa, shows that saucer-shaped sills are common in the middle and upper parts of the basin. Similar saucer shaped sill complexes are also mapped on new two- and three-dimensional seismic data offshore of Mid-Norway and on the NW Australian shelf, whereas planar and segmented sheet intrusions are more common in structured and deep basin provinces.
Sedimentary dolomite: a reality check
Authors: Wright David T. , Wacey David 
Published: April 2008

Abstract
The failure to precipitate dolomite experimentally at low temperatures or from seawater in which it is both supersaturated and the most thermodynamically favoured carbonate phase, together with its unequal distribution through geological time relative to limestone, are all aspects of the ‘dolomite problem’, a subject of continuing controversy. A plethora of physicochemical models has been invoked to explain sedimentary dolomite formation, none of which satisfactorily addresses the basic problem of how kinetic barriers are overcome. These barriers are related to the disproportionate distribution of the component ions of dolomite, cation hydration and ion complexing in seawater. Competing claims for the effectiveness of sulphate as an inhibitor to dolomite formation further confuse the debate, although there are many reports of modern dolomite associated with bacterial sulphate reduction. The uppermost sediments in some lakes of the Coorong region of South Australia comprise almost 100% dolomite, and afford an ideal opportunity to study this association.
Samples of lake waters taken during late evaporative stages of several shallow hypersaline dolomitic lakes showed high initial sulphate concentrations, high pH and high carbonate alkalinities. Pore waters from unlithified lake sediment cores directly below the lake-water sample sites showed a substantial and progressive decrease in sulphate concentrations with depth, coupled with an exponential increase in carbonate concentrations, through the sulphate-reduction zone. By the end of the evaporative cycle, sulphate was entirely removed. High bacterial counts on cultures from the sediment cores, and sulphur isotope values consistent with ‘bacterial’ fractionation in lake waters, indicate that the chemical changes in ambient water chemistry can be related to active bacterial sulphate reduction. Laboratory experiments using sulphate reducers cultured from the lake sediments and simulating the anoxic microbiogeochemical environment of the lakes, have resulted in the precipitation of dolomite, demonstrating that bacterial sulphate reduction in the Coorong lakes modifies lake-water and pore-water chemistry so that dolomite precipitation is kinetically favoured.
Given the wide spatial and temporal distribution of sulphate-reducing bacteria, and their frequent association, both past and present, with cyanobacteria, it is likely that this process was more widespread in the geological past when dolomite was found in far greater abundance than limestone. Bacterial sulphate reduction may thus have played an important role in dolomite formation throughout the geological record.
Basin fluid flow, base-metal sulphide mineralization and the development of dolomite petroleum reservoirs
Authors: Gregg Jay M. 
Published: April 2008

AbstractSaline basinal fluids, at temperatures from 60 to 250 °C, have affected almost every sedimentary basin in the world including rocks from Palaeoproterozoic to Cenozoic age. These fluids commonly precipitate base-metal sulphides (pyrite, sphalerite, galena, etc.) and associated minerals (barite, fluorite, calcite, dolomite, etc.) ranging in volume from trace amounts to large economic ore deposits. Such deposits are commonly referred to as Mississippi Valley-type (MVT) after the large Palaeozoic deposits of this kind found in the Mississippi Valley of North America. They are primarily hosted by platform carbonates, typically dolomite, and are usually associated with hydrocarbons.Dolomites not affected by mineralizing fluids commonly display micron- to decimicron-size planar textures, and have well-developed micro- and mesoporosity networks dominated by intercrystal and vug porosity. However, these and other carbonate rocks affected by basinal fluids may undergo massive geochemical and textural alteration. This occurs even when the affected rocks are distal from the main loci of sulphide mineralization. Alteration includes: dolomitization of limestone; neomorphic recrystallization of existing dolomite; and precipitation at intervals of large volumes of open-space-filling dolomite, calcite and quartz cements alternating with dissolution. Dolomitization of limestone and/or neomorphic recrystallization of dolomite, at elevated temperatures, commonly results in centimicron and larger size crystals, and development of nonplanar textures that increase pore-throat tortuosity. Open-space-filling dolomite, calcite and quartz cementation causes a dramatic reduction of porosity and blockage of pore throats. Periods of carbonate dissolution, proximal to intense sulphide mineralization, result in the development of large-scale macroporosity such as breccias that are commonly superimposed on karst and tectonic fractures.Exposure to mineralizing basinal fluids substantially alters porosity and permeability distribution, and thus the potential reservoir properties of the dolomite. The resulting reservoir may have little resemblance to its precursor. Understanding the epigenetic history of a dolomite is critical, therefore, as this will ultimately affect its development strategy and production history.
Patterned dolomites: microbial origins and clues to vanished evaporites in the Arab Formation, Upper Jurassic, Arabian Gulf
Authors: Kirkham A. 
Published: April 2008

Abstract
The common occurrence of patterned dolomites in the upper Arab Formation of the Arabian Gulf is highlighted. Their mottled appearance is due to concentrations of microcrystalline iron sulphide. The dolomites are typically devoid of bioclastic debris and are usually interbedded with stromatolites and thin carbonates, both of which commonly contain anhydrite nodules. Previous workers have interpreted the patterned appearance as originating from birds-eye porosity, burrowing activity or plant roots, but their mottled appearance, and possibly also the dolomite, probably originated as a by-product of the activities of sulphate-reducing bacteria in water-logged or subaqueous sediments on the floors of salinas or very highly saline lagoons from which dissolved sulphate and/or gypsum had been removed. This implies that the Arab Formation was originally locally even more gypsiferous than is evident from its existing bedded anhydrites. The related processes of sulphate removal and sulphide formation were penecontemporaneous, as shown by occurrences of the mottled fabrics as intraclasts. Contorted lamination within the patterned dolomites and their frequent involvement with sediment injection structures are evidence of fluidization. Reasons for the contortion and fluidization are considered with respect to compatible Holocene depositional and diagenetic environments. In addition to the comparatively simple depositional models of extensively prograding supratidal sabkhas, which are traditionally applied to facies associations of stromatolites and bedded anhydrites in the Arab Formation, the presence of patterned dolomites demands consideration of less continuous and static facies belts with reduced correlatability that imply higher levels of reservoir heterogeneity.
Contrasting patterns of pore-system modification due to dolomitization and fracturing in Dinantian basin-margin carbonates from the UK
Authors: Bouch Jon E. , Milodowski Antoni E. , Ambrose Keith 
Published: April 2008

Abstract
Two examples of Dinantian basin-margin carbonates from the United Kingdom provide potential analogues for fracture and porosity distributions in hydrocarbon reservoirs in dolostones. In both examples pore systems have been extensively modified by dolomitization, fracturing and related mineralization. However, the detailed processes and the end results show some significant differences, highlighting the importance of developing an understanding of the specific pore-system modifying processes when characterizing and modelling porosity distributions in these settings.
In the first example, predominantly low-porosity and low-permeability limestones in Lower Carboniferous inliers in Leicestershire (Cloud Hill) and south Derbyshire (Ticknall) had their pore systems further degraded by extensive dolomitization. Subsequent fracturing and related mineralization were responsible for significant porosity generation adjacent to fractures.
In contrast, in the Sellafield area (west Cumbria), dolomitization was strongly controlled by fractures that were also mineralized by sulphate-rich brines. In the north of the area fractures were filled with an assemblage of barite-fluorite-hematite-calcite that is resistant to corrosion by low-temperature meteoric groundwater. However, in the south of the area the fractures were cemented by anhydrite, which is readily corroded by saline, but sulphatepoor, groundwater formed by percolating meteoric recharge from the east. Progressive dissolution has been ongoing since Tertiary uplift, and has rejuvenated fracture porosity within the dolomitized limestones.
Geometry and origin of dolomudstone reservoirs: Pekisko Formation (Lower Carboniferous), western Canada
Authors: Hopkins John C. 
Published: April 2008

Abstract
Dolomudstones of the Pekisko Formation in western Canada form small but important oil and gas reservoirs. The reservoirs are irregularly shaped bodies 1 km or so wide and commonly 5–8 m thick. Porosity development within the dolomudstones is a complex function of sedimentation, early facies-selective dolomitization and later telogenetic leaching of calcareous components.
The carbonate sediment precursor of the dolomudstone, interpreted from relict textures preserved in chert nodules, was a microwackestone with abundant silt-sized skeletal fragments. Dolomudstone reservoirs are comprised of dolomudstones, calcareous dolomudstones, and subordinate interbedded dolowackestones and dolograinstones. Some dolomudstone reservoirs are contained entirely within grainstones. Others are capped by tight fenestral lime mudstone that has been dolomitized locally. Dolomitization has been most intense within the centres of these reservoirs, and dolomudstones grade laterally into calcareous dolomudstones.
The association of facies indicates that microwackestones were deposited in subtidal intershoal and lagoonal environments on an inner ramp. Grainstone shoals provided a broad barrier that absorbed wave energy seaward of the lagoon. Fenestral lime mudstones accumulated in peritidal environments in restricted areas of the inner ramp, landward of the lagoon. Dolomitization is interpreted to have been early and selective to the microwackestone facies because it retained permeability or was reactive during early burial. Dolomitizing fluids were most probably derived from overlying formations and made their way downwards through spatially separated conduits. The Pekisko Formation was exposed and sculptured at several Jurassic-Early Cretaceous unconformities. During these times, sandstones and shales were deposited in solution cavities developed within the dolomudstones. Concomitant leaching of calcite increased porosity of the dolomudstone reservoirs.