bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigating multi-element soil geochemical signatures and their potential for use in forensic studies
Authors: Rawlins B. G. , Cave M. 
Published: April 2008

Abstract
Data from a regional soil survey in eastern England have been used to determine whether samples over the same parent material can be discriminated on the basis of both individual and multielement geochemistry. Discrimination was based on estimates of measurement uncertainty, which were calculated from the analysis of a series of duplicates and subsamples. In the multivariate analysis we estimated a covariance matrix for the two sources of uncertainty and compared this to Mahalanobis distances calculated for pairs of samples within each parent material group. For 12 of the 19 individual elements, it was possible on average to discriminate between more than 80% of the samples within parent material groups and typically between 15 and 17 of the 19 elements discriminated individual samples. In the multi-element analysis, typically more than 99.8% of samples within the same parent material group were discriminated from one another. Hence, the geochemistry of a natural soil sample, when collected and analysed according to a strict protocol, and compared to a database that adopted the same methods, could be used to help establish provenance within bedrock-derived soil types. However, there are significant differences between the nature of soil samples and the way they are collected or derived in soil surveys and forensic investigations. These questions need to be addressed thoroughly before any practical application to forensic cases in which an investigator is attempting to link a suspect to a location based on soil geochemical signatures.
Defining ‘local signature’ in terms of Sr isotope composition using a tenth- to twelfth-century Anglo-Saxon population living on a Jurassic clay-carbonate terrain, Rutland, UK
Authors: Evans J. A. , Tatham S. 
Published: April 2008

Abstract

The Sr isotope ratios and Sr concentration in tooth enamel from a rural tenth-twelfth century Anglo-Saxon population living on a Jurassic clay-carbonate terrain in eastern England gives the following mean values:
87
Sr/
86
Sr=0.7098±0.0018 (2σ,
n
=22) and Sr concentrations = 74±62 p.p.m. (2σ). The isotope data are taken to be representative of Anglo-Saxon biosphere values in the area of study. The Sr isotope composition of soil leachates, plant material, riverwaters and animal tooth enamel associated with the burial site were all analysed to see which gave the best approximation to these local Anglo-Saxon values, the aim being to define the best method of predicting the local Sr signature of areas for archaeological purposes. The Sr isotope composition of acetic acid soil leachates were dominated by the carbonate soil component and gave 0.7085±0.0020 water leachates gave 0.7090±0.0014 and plant material gave 0.7092±0.0018 (all at 2σ,
n
=12). All of these materials were less radiogenic that those of the Anglo-Saxon population. Riverwater gave the same result as the plants at 0.7092±0.0012 (2σ,
n
=3). The Anglo-Saxon animal tooth enamel gave the best match with a value of 0.7099±0.0017 (2σ,
n
=13). Analysis of variance (ANOVA) tests show that there is a high probability (>70% probability, 2SD) that the animals and the humans sampled were from the same population with respect to Sr isotope composition. Thus animal tooth enamel proved to be the best proxy, in this study, for the local human population.
Why do we need to consider geological storage of CO
2
Authors: Gale John 
Published: April 2008

Abstract

To meet targets for greenhouse gas emission reduction set by the Kyoto Protocol, many countries are considering a range of near-term options such as, fuel switching, energy efficiency improvements and use of renewable sources of energy, to reduce their greenhouse gas emissions. However, to meet the goal of the UN Framework Convention on Climate Change, namely stabilization of greenhouse gas concentrations in the atmosphere, it is likely that deeper reductions in emissions will be needed. This will require additional measures such as the geological storage of CO
2
. Geological storage of CO
2
would be used to sequester CO
2
captured from large anthropogenic sources, such as power and large industrial plants. There are a number of reservoirs suitable for geological storage of CO
2
including depleted oil and gas fields and deep saline aquifers. Many of these reservoirs have stored hydrocarbons and fluids for million of years, which gives confidence that CO
2
can be stored for similar durations, but research is needed to confirm this.
Analysis of CO
2
leakage through ‘low-permeability’ faults from natural reservoirs in the Colorado Plateau, east-central Utah
Authors: Shipton Z. K. , Evans J. P. , Kirschner D. , Kolesar P. T. , Williams A. P. , Heath J. 
Published: April 2008

Abstract

The numerous CO
2
reservoirs in the Colorado Plateau region of the United States are natural analogues for potential geological CO
2
sequestration repositories. To understand better the risk of leakage from reservoirs used for long-term underground CO
2
storage, we examine evidence for CO
2
migration along two normal faults that cut a reservoir in east-central Utah. CO
2
-charged springs, geysers, and a hydrocarbon seep are localized along these faults. These include natural springs that have been active for long periods of time, and springs that were induced by recent drilling. The CO
2
-charged spring waters have deposited travertine mounds and carbonate veins. The faults cut siltstones, shales, and sandstones and the fault rocks are fine-grained, clay-rich gouge, generally thought to be barriers to fluid flow. The geological and geochemical data are consistent with these faults being conduits for CO
2
moving to the surface. Consequently, the injection of CO
2
into faulted geological reservoirs, including faults with clay gouge, must be carefully designed and monitored to avoid slow seepage or fast rupture to the biosphere.
The impact of chemical reactions on CO
2
storage in geological formations: a brief review
Authors: Rochelle C. A. , Czernichowski-Lauriol I. , Milodowski A. E. 
Published: April 2008

Abstract

The sequestration of CO
2
in the deep geosphere is one potential method for reducing anthropogenic emissions to the atmosphere without a drastic change in our energy-producing technologies. Immediately after injection, the CO
2
will be stored as a free phase within the host rock. Over time it will dissolve into the local formation water and initiate a variety of geochemical reactions. Some of these reactions could be beneficial, helping to chemically contain or ‘trap’ the CO
2
as dissolved species and by the formation of new carbonate minerals; others may be deleterious, and actually aid the migration of CO
2
. It will be important to understand the overall impact of these competing processes. However, these processes will also be dependent upon the structure, mineralogy and hydrogeology of the specific lithologies concerned and the chemical stability of the engineered features (principally, the cement and steel components in the well completions). Therefore, individual storage operations will have to take account of local geological, fluid chemical and hydrogeological conditions. The aim of this paper is to review some of the possible chemical reactions that might occur once CO
2
is injected underground, and to highlight their possible impacts on long-term CO
2
storage.
The impact of geological heterogeneity on CO
2
storage in brine formations: a case study from the Texas Gulf Coast
Authors: Hovorka Susan D. , Doughty Christine , Benson Sally M. , Pruess Karsten , Knox Paul R. 
Published: April 2008

Abstract

Geological complexities such as variable permeability and structure (folds and faults) exist to a greater or lesser extent in all subsurface environments. In order to identify safe and effective sites in which to inject CO
2
for sequestration, it is necessary to predict the effect of these heterogeneities on the short- and long-term distribution of CO
2
.

Sequestration
capacity
, the volume fraction of the subsurface available for CO
2
storage, can be increased by geological heterogeneity. Numerical models demonstrate that in a homogeneous rock volume, CO
2
flowpaths are dominated by buoyancy, bypassing much of the rock volume. Flow through a more heterogeneous rock volume disperses the flow paths, contacting a larger percentage of the rock volume, and thereby increasing sequestration capacity.

Sequestration
effectiveness
, how much CO
2
will be sequestered for how long in how much space, can also be enhanced by heterogeneity. A given volume of CO
2
distributed over a larger rock volume may decrease leakage risk by shortening the continuous column of buoyant gas acting on a capillary seal and inhibiting seal failure. However, where structural heterogeneity predominates over stratigraphic heterogeneity, large columns of CO
2
may accumulate below a sealing layer, increasing the risk of seal failure and leakage.
Geological sequestration of CO
2
in the subsurface: lessons from CO
2
injection enhanced oil recovery projects in oilfields
Authors: Worden Richard H. , Smith Leta K. 
Published: April 2008

Abstract

In this paper production geochemical data from oil fields where CO
2
has been injected to enhance oil recovery (CO
2
-EOR) and experimental simulations of this process are reviewed. These data show that over the timescale of days to many years, CO
2
injected into the subsurface typically results in the bulk dissolution of carbonate minerals. There is little evidence for the sequestration of the injected greenhouse gas as a solid phase carbonate mineral on the timescale of the CO
2
-EOR projects or experiments. There is extensive aqueous geochemical, petrographic and core analysis evidence that supports the conclusion that CO
2
, injected into oil fields to enhance secondary recovery, leads to the bulk dissolution of calcite, dolomite and siderite. Although carbonate dissolution leads to enhanced porosity, the expected commensurate increase in permeability may be offset by the migration of clays, liberated by the action of the acidic water on the rock, with consequent blocking of pore throats. Additionally, injection of CO
2
into oil fields can result in asphaltene deposition on mineral surfaces. Such a bitumen coat could ultimately isolate the mineral matrix from injected fluids and insulate the rock to the injected greenhouse gas. Localized precipitation of calcite scale has been reported in the topside facilities of CO
2
-EOR projects and in the low-pressure region of experimental simulations.
Monitoring experience associated with nuclear waste disposal and its application to CO
2
sequestration projects
Authors: Stenhouse Michael J. , Savage David 
Published: April 2008

Abstract

Monitoring is a key component of the development and operation of nuclear waste repositories, and some of the underlying considerations and lessons learned can benefit projects involving the geological storage of CO
2
. Before reviewing the general monitoring objectives for nuclear waste repositories, the key differences between nuclear waste disposal and CO
2
storage projects are emphasized. The philosophy underlying monitoring after closing/sealing a repository is discussed. Important aspects of this philosophy include the need to collect adequate baseline data representative of the unperturbed site, and the desire to engender public confidence, but not at the expense of compromising the protective barriers of the repository itself. Pre-operational and operational monitoring provide important data that feed into safety assessment calculations, either as input data or as information that can be used to confirm, and/or refine, predictions. Using a specific example of a deep (geological) repository, monitoring experience at the WIPP site in New Mexico is discussed, focusing on methods and techniques that are relevant to CO
2
sequestration projects. Such monitoring includes geotechnical (characterization of the evolving behaviour of underground facilities), groundwater (quality and quantity), environmental (impacts on ecosystems), and subsidence (to support subsidence predictions for the WIPP site located in bedded salt formations).
Peperitic lava lake-fed sills at Ság-hegy, western Hungary: A complex interaction of a wet tephra ring and lava
Authors: Martin Ulrike , Németh Károly 
Published: April 2008

Abstract

Ság-hegy is the remnant of a complex volcano consisting of several phreatomagmatic pyroclastic sequences preserved in immediate contact with a thick (
c.
50 m) coherent lava body. Due to the intensive quarrying, the inner part of the lava has been removed, leaving behind a castle-like architecture of pyroclastic rocks. The outcrop walls thus demonstrate the irregular morphology of the lava, which was emplaced in a NW-SE-trending ellipsoidal vent zone in a phreatomagmatic volcano. Pyroclastic beds in the quarry wall are cross-cut by dykes and sills, inferred to have been fed from a central magma zone. Thin (<10 cm) strongly chilled, black, angularly jointed aphanitic basaltic lava mantles the pyroclastic sequence, and has a corrugated margin as a consequence of sudden chilling against the cold and wet phreatomagmatic tephra in the inner wall of the tuff ring crater. These corrugated zones are inferred to be a characteristic textural feature, indicating extensive mixing of lava and host tephra which led to peperite formation along the outer rim lava lake. A spectrum of peperite formed along the lake margin, and fluid oscillation, due to fluidization of the wet tephra, disrupted a steam envelope formed around the lava, causing basaltic magma to invade and mix with the phreatomagmatic tephra. The presence of unconformities in the tephra ring facilitated the formation of sills fed from the central lava body.
Depth, geometry and emplacement of sills to laccoliths and their host-rock relationships: Montecampione group, Southern Alps, Italy
Authors: Corazzato Claudia , Groppelli Gianluca 
Published: April 2008

Abstract

This study focused on a set of shallow subvolcanic bodies, mainly laccoliths and sills, that intruded the Upper Permian-Lower Triassic sedimentary sequence of the central Southern Alps, in the area of Montecampione (Val Camonica, Italy). These intrusions represented a shallow magmatic reservoir probably associated with Triassic volcanism. Based on a detailed stratigraphic reconstruction, this paper presents results dealing with the evaluation of the emplacement depth, the estimated volume of the subvolcanic bodies, a description of their geometries, and their relation to the host rock and response of the sedimentary units to the intrusions. The emplacement depth was estimated using the thickness of the sedimentary overburden at the time of emplacement, and by applying simple equations involving laccolith dimensions. The results are comparable, and support an average emplacement depth of about 1300 m. The minimum volume of the intrusions was obtained using a GIS, and is about 1 km
3
. Concerning the relationship between the intrusive bodies and the host rock, we observed that sills are mainly emplaced into the Servino Formation, while the laccoliths are emplaced near the contact between the Verrucano Lombardo and the Servino Formation. The two sedimentary units show a different response to the intrusion: the Verrucano Lombardo always appearing fractured and tilted, while the Servino Formation shows a range of deformation patterns, from light ductilization at the contact, to folding, brecciation and foliation. These different responses reflect the mechanics of emplacement and geometry of the intrusions, and local heterogeneities in the host rock. Both units show a local thermal effect close to the contact.
Reservoir properties of Arab carbonates, Al Rayyan Field, offshore Qatar
Authors: Clark David , Heaviside John , Habib Kassim 
Published: April 2008

Abstract
Oil is present in the Upper Jurassic Arab A and Arab C carbonates of the Al Rayyan Field. The Arab A consists of porous limestone with thin units of tight dolomite at the top and bottom. Two reservoir intervals can be distinguished, separated by a slightly less permeable unit. The upper reservoir consists of stromatolites and cross-bedded peloidal-grainstones, whereas the lower reservoir consists predominantly of ooliticgrainstones. The less permeable unit comprises moderately cemented, cross-bedded peloidal-grainstones. Higher porosity and permeability generally occurs in the coarser grained, cross-bedded grainstones, where pores are mostly primary and intergranular; lower permeability is characteristic of grainstones with moderately developed early cement. Porosity is enhanced at some levels by the presence of leached intragranular pores, but these have little effect on permeability. The Arab C is strongly stratified and completely dolomitized. Three reservoir intervals can be recognized, separated by less permeable layers of poorer quality rock. The upper reservoir consists of partially leached and moderately cemented, cross-bedded bioclastic-peloidal-grainstones. Porosity is high because of the presence of leached intragranular pores in addition to primary intergranular pores but permeability is relatively low because of the presence of early cement. The main reservoir comprises loosely compacted and lightly cemented, cross-bedded peloidal-grainstones. Porosity is lower than that in the upper reservoir because leached intragranular pores are generally absent, but permeability is higher because cementation is relatively light. The lower reservoir is made up of peloidal-grainstones and coarse-grained bioclastic-grainstones. The upper and main reservoirs are separated by a thick interval of relatively tight, thinly bedded, strongly cemented peloidal-grainstones, whereas the main and lower reservoirs are separated only by a thin bed of tight, nodular anhydrite. The pore types and cements observed in the Arab C are similar to those of the Arab A, but dolomitization has resulted in an enhancement of permeability and capillary pressure properties compared to those of the Arab A. Thus, the overall water saturation of the Arab C is lower than that of the Arab A, and the displacement pressures and irreducible water saturations are also significantly lower than those of Arab A carbonates.
The geochemical behaviour of Tc, Np and Pu in spent nuclear fuel in an oxidizing environment
Authors: Buck Edgar C. , Hanson Brady D. , McNamara Bruce K. 
Published: April 2008

Abstract

Spent fuel from commercial nuclear reactors consists mainly of uranium oxide. However, the changes that occur during reactor operations have a profound effect on chemical and physical properties of this material. Heat build-up in the fuel pellet during reactor operations can cause redistribution of fission products. The fission products may aggregate in one of three types of precipitates; gaseous, metallic, or oxide, depending on the burn-up and in-core treatment. Radiation damage and variations in fission and neutron capture yields across the fuel pellets lead to Pu enrichment and increased porosity with increasing burn-up. A more porous surface may make the fuel more susceptible to oxidative dissolution. As the level of actinides and fission products increases, the fuel may become more resistant to oxidation. These changes may limit the usefulness of natural uraninite (UO
2
) analogues for predicting the geological behaviour of spent fuel disposed in a high-level waste (HLW) repository. In this Chapter, an overview of spent fuel microstructure, radiolytic effects, and alteration processes is presented. Evidence for Np incorporation into U
6+
phases, the nature of Pu surface precipitates on spent fuel, and evidence for the preferential removal of 4d-metals from ε-particles in corroded spent fuel is discussed. Understanding the potential mechanisms of radionuclide attenuation through sorption and/or incorporation requires techniques with both high spatial resolution and excellent elemental sensitivity.
Geochemical behaviour of host phases for actinides and fission products in crystalline ceramic nuclear waste forms
Authors: Lumpkin Gregory R. , Smith Katherine L. , Gieré Reto , Williams C. Terry 
Published: April 2008

Abstract

A number of polyphase or single-phase ceramic waste forms have been considered as options for the disposal of nuclear waste in geological repositories. Of critical concern in the scientific evaluation of these materials is their performance in natural systems over long periods of time (e.g., 10
3
to 10
6
years). This paper gives an overview of the aqueous durability of the major titanate host phases for actinides (e.g., Th, U, Np, Pu, Cm) and important fission products (e.g., Sr and Cs) in alternative crystalline ceramic waste forms. These host phases are compared with reference to some basic acceptance criteria, including the long-term behaviour determined from studies of natural samples. The available data indicate that zirconolite and pyrochlore are excellent candidate host phases for actinides. These structures exhibit excellent aqueous durability, crystal chemical flexibility, high waste loadings, and well-known processing conditions. Although both pyrochlore and zirconolite become amorphous due to alpha-decay processes, the total volume swelling is only 5–6% and there is no significant effect of radiation damage on aqueous durability. Hollandite also appears to be an excellent candidate host phase for radioactive Cs isotopes. Brannerite and perovskite, on the other hand, are more prone to alteration in aqueous fluids and have a lower degree of chemical flexibility. With the exception of hollandite, many of the properties of these potential host phases have been confirmed through studies of natural samples.
Special cases of natural analogues: The Gabon and Cigar Lake U ore deposits
Authors: Gauthier-Lafaye F. , Stille P. , Bros R. 
Published: April 2008

Abstract

The Gabon and Cigar Lake uranium deposits may be used as natural analogues for nuclear waste because they both provide information on actinide immobilization in a geological system over a very long period of time. These deposits contain high-grade uranium ores (40–60% UO
2
) embedded in a clay matrix. Futhermore, the Oklo and Bangombé uranium deposits in Gabon were natural nuclear fission reactors that operated 2000 Ma ago. This offers the unique opportunity to study the behaviour of fission products and actinides in a geological environment. The geological stability of the sites is one of the most important parameters that can explain the preservation of the natural reactors of Gabon and of the Cigar Lake deposit. The mineralogy of the hosted rocks and the chemical composition of the fluids are likewise important parameters. It can be shown that clays, Fe-sulphides and organic matters provide effective redox buffering and consequently play an important role in the long-term preservation of the ores. Adsorption of actinides and fission products on clays and Ti-oxides is also an important process for retention of these elements. This process is even more efficient when it is followed by the formation of coffinite, USiO
4
·
n
H
2
O. Coffinitization is common at the Cigar Lake deposit and in the natural reactors of Gabon. Coffinitization may be related to hydrothermal alteration (Cigar Lake) and to weathering (Bangombé).