bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of point source pollution by chlorinated solvents in two different geologies: a multi-layered Carboniferous sandstone-mudstone sequence and the Chalk
Authors: Bishop P. K. , Lerner D. N. , Stuart M. 
Published: April 2008

Abstract
Two investigations of point source chlorinated solvent pollution of groundwater from very different settings are described: an industrial site in Coventry underlain by a multi-layered Carboniferous sandstone-mudstone sequence, and a village site (Sawston) underlain by Chalk in rural eastern England. The investigations are probably two of the most comprehensive studies of point source pollution by solvents in the UK. Both followed a phased approach with key elements being soil gas surveys, and definition of vertical pollution profiles through development of multi-level groundwater sampling and pore-water extraction techniques. The studies identified very significant contamination by chlorinated solvents, trichloroethene and 1,1,1-trichloroethane in the case of the Coventry site, and tetrachloroethene in the case of the Sawston site. The non-aqueous solvent phase was not detected at either site. The main similarities and differences between the studies are brought out, and the successes and failures of the studies discussed. The main successes are considered to be the development of effective soil gas and pore-water sampling methods, and sampling methods for determining vertical variations in groundwater quality. The main failures are considered to be the occurrence of cross-contamination at the Coventry site and the failure to accurately define pollution plumes. An ideal methodology is presented for future investigations, involving a phased approach maximizing the quality of information gained in each phase and preventing cross-contamination.
The retardation and attenuation of liquid radioactive wastes due to the geochemical properties of the zone of injection
Authors: Solodov Igor N. 
Published: April 2008

Abstract
Natural geochemical factors are of significant importance for the design of underground waste disposal systems and their subsequent operation. Analysis of geochemical similarities between liquid radioactive waste (LRW) disposal sites and sulphuric acid uranium-leaching mines in sandy aquifer horizons, has proved to be a productive approach, permitting predictive understanding of the hydrogeochemical processes which might develop in aquifer horizons subject to the injection of LRW. The approach allows the attenuative geochemical properties of terrigenous aquifers to be estimated. It is demonstrated that a number of geochemical processes (neutralization, reduction, sorption, precipitation, pore occlusion and radiolysis) in the injection zone of such aquifers may lead to attenuation, degradation and solid-phase immobilization of contaminants associated with LRW.
Turbidite flux, architecture and chemostratigraphy of the Herodotus Basin, Levantine Sea, SE Mediterranean
Authors: Reeder Mike , Rothwell Guy , Stow Dorrik A. V. , Kahler Gisela , Kenyon Neil H. 
Published: April 2008

Abstract

The Herodotus Basin is the deepest part of the SE Mediterranean and receives allochthonous sediments as turbidity currents and debris flows from around its margin. During the late Quaternary, characteristic supply has been from at least four sources. These are (1) dark coloured, calcium carbonate-poor fine-grained turbidites derived from the Nile Cone to the south and south-east, (2) lighter coloured, calcium carbonate-rich, slightly coarser-grained turbidites derived from the Libyan-Egyptian shelf to the south, (3) small, light brown foraminifer-rich, muddy-silty turbidites derived from the Cyprus-Eratosthenes seamount (Anatolian Rise) carbonate shelf to the east, and (4) small localized debris flow deposits derived from the Mediterranean Ridge to the north. During the late Quaternary (0–60 ka), and specifically the period of 0–27 ka, the basin has filled predominantly with allochthonous material derived from the Nile Cone, although one megaturbidite of basinwide extent was derived from the Libyan-Egyptian shelf. Turbidites have been correlated across the Herodotus Basin using the technique of chemostratigraphy. Matching the results of geochemical analysis may show whether or not the beds in different cores were deposited by the same mass-wasting event, for individual turbidites commonly have diagnostic and unique geochemical ‘fingerprints’ in terms of major, minor and trace element composition. Sediment budgets for the three main turbidite sources are calculated. The cumulative volume of the sedimentary input for the Nile Cone- derived turbidites over the last 27 ka is
c.
500 km
3
, giving an average sedimentation rate of
c.
45 cm ka
−1
, and a volume per unit time of 18 km
3
ka
−1
. A megaturbidite, derived from the Libyan-Egyptian shelf, is of basinwide extent and has a volume of
c.
400 km
3
.
The British Nuclear Fuels Drigg low-level waste site characterization programme
Authors: Sears Rob 
Published: April 2008

Abstract
Site characterization work is being undertaken to underpin the post-closure radiological assessment of the UK’s Drigg low-level radioactive waste disposal site. This work is providing high-quality data on the geology, hydrology and hydrogeology of the site, thus ensuring that both the monitoring programme and predictions of the radiological impact are based on a good understanding of the hydrogeology.
The programme has two phases. The first addresses the surface water balance of the site; this has been achieved by constructing a surface water balance model which has been combined with a forest interception model to determine the hydrologically effective rainfall. This model has been calibrated using extensive soil moisture data gathered on-site. The second phase is concerned with improving knowledge of the site geology and hydrogeology. Continuously cored rotary boreholes are being drilled across the site to recover geological data. Additionally, a complementary geophysical programme and trial trench studies have been undertaken. Hydrogeological data are being provided by a series of borehole clusters, drilled using cable percussion rigs, centred around the rotary boreholes. During the drilling of the cable percussion boreholes, extensive hydrogeological and hydrogeochemical data are being acquired. These data, in conjunction with data from weirs on the site streams, will provide the data required to complete the hydrogeological water balance.
Groundwater resource development and protection considerations for the Ogallala Formation in Ogallala, Nebraska
Authors: Gabriel William J. , Mason John M. , Gottler Paul F. 
Published: April 2008

Abstract

The Ogallala Formation is the primary stratigraphic unit of the High Plains Aquifer which comprises the largest fresh-water aquifer in the United States. The Ogallala Formation covers approximately 450 500 km
2
extending from South Dakota to west Texas and eastern New Mexico. This study focuses on the hydrogeological characteristics and resource management of the Ogallala Formation in the type locality of Ogallala, Nebraska. For this study, the geology of the Ogallala Formation was evaluated using outcrops and sub-surface data. The hydrogeological and geochemical properties of the aquifer were also characterized to assess groundwater flow and analyte distributions. The study revealed two distinct hydrostratigraphic units separated by an aquitard. Groundwater analyses indicated that the upper unit contained high concentrations of sulphate which would preclude its use as a potable water source, but that it could be used for industrial or agricultural purposes. In contrast, water in the lower unit was of high quality, and it is currently used for drinking water supply. However, water supply well construction allowed the hydraulic connection of these two units. The study concluded that adequate aquifer characterization prior to developing this groundwater resource is essential for proper development. Specifically, the proper design of pumping wells to limit the potential for mixing of non-potable water from the upper zone with high quality water within the lower unit should be considered.
Estimation of groundwater recharge on Jersey
Authors: Blackie J. R. , Houghton-Carr H. A. , McCartney M. P. , Moores J. P. 
Published: April 2008

Abstract
There has been growing concern that groundwater abstraction on the island of Jersey may exceed recharge, with the consequent depletion of the island’s finite water resources. A three-year study to determine groundwater recharge through hydrological modelling is nearing completion. A daily model has been developed which predicts evapotranspiration, soil moisture, recharge and streamflow from inputs of rainfall and potential evapotranspiration. Preliminary calibration of the model has used data collected from a small, intensively instrumented catchment around Trinity, Jersey, between April 1993 and December 1994. Subsequent validation, for the pre-study period January 1990 to December 1992, has shown estimated net recharge for the catchment as a whole to be 50 mm, with an initial depletion of groundwater reserves in 1990 followed by two years of positive recharge. Net recharge under a grass site was estimated to be slightly more than under arable land. Model calibration and validation will be reworked following collation of the 1995/96 dataset. The model will then be run on 25 years of catchment rainfall and potential evapotranspiration data to estimate recharge patterns over the period 1968–92, and to assess the impact of different abstraction rates.
Methods used to delineate groundwater source protection zones in England and Wales
Authors: Burgess D. B. , Fletcher S. W. 
Published: April 2008

Abstract
Groundwater source protection zones (GPZs) are an integral part of land surface zoning within the Environment Agency’s Policy and Practice for the Protection of Groundwater. The methods and experience gained in delineating GPZs around 1000 groundwater sources in England and Wales are reviewed. The methods include: manual calculations, hydrogeological mapping, analytical and semi- analytical modelling and numerical modelling. The large numbers of sources within a diverse number of hydrogeological settings has led to a structured approach to selecting the GPZ method appropriate to each groundwater source. This includes consideration of the protected yield, data acquisition and formulation of a conceptual flow model. The GPZ methods also include consideration of parameter uncertainty. Further developments in GPZ delineation methods are required to cope with fissured/fractured groundwater flow and to exploit the results of transient groundwater models.
Lower Palaeozoic reservoirs of North Africa
Authors: Crossley Rob , McDougall Neil 
Published: April 2008

Abstract
This paper provides an overview of features considered significant in the exploration and development of Lower Palaeozoic reservoirs of North Africa. Information is derived from a review of literature on the Lower Palaeozoic successions of north Africa, combined with outcrop observations from the Anti Atlas mountains of Morocco. The focus of the exploration-oriented part of the review is on identification of potential traps other than two-way structural dip closure. Stratigraphic elements described include depositional models of reservoir facies, tectonic unconformities and possible eustatic unconformities. Cases of established or potential trapping by post-depositional faulting, by diagenesis and by hydrodynamic flow are examined. Development-related topics highlighted include the impact on reservoir matrix quality of burial diagenesis and of palaeo-weathering at the Hercynian unconformity. Other issues discussed which additionally affect producibility from the reservoir matrix include tectonic fracturing, palaeotopography and unloading fracturing at the Hercynian unconformity, and induced fracturing within the present stress regimes.
The lithostratigraphy of the latest Triassic to earliest Cretaceous of the English Channel and its adjacent areas
Authors: Ainsworth Nigel R. , Braham William , Gregory F. John , Johnson Ben , King Christopher 
Published: April 2008

Abstract
The stratigraphy of the latest Triassic through to the earliest Cretaceous of the Portland-Wight Basin and its adjacent areas may be subdivided using petrophysical (gamma-ray and interval transit time) criteria, in association with gross lithology to allow a total of 50 lithological units to be recognized. Three units occur within the latest Triassic, 46 in the Jurassic and one in the earliest Cretaceous. The lithostratigraphy can be integrated into a biostratigraphic template using published data and subsequent observations based on micropalaeontology (ostracods, foraminiferids) and palynology (dinocysts, miospores). Throughout the study area recognition of major lithostratigraphic and biostratigraphic events enables the chronostratigraphic framework of the basin to be determined, which has aided identification of regional stratigraphic breaks throughout much of the Portland Wight Basin, including haitii in proximity to the Pliensbachian-Toarcian and the Aalenian-Bajocian boundaries, and also within the Late Oxfordian. Although the majority of the lithostratigraphic events have been deduced to be isochronous, a number of lithological units exhibit significant diachroneity. These specifically include the Frome Clay and the Great Oolite, the Kellaways Sand Member and Clay Member, and the Sandsfoot Grit Formation and the Ampthill Clay Equivalent.
Tectonic accentuation of sequence boundaries: evidence from the Lower Cretaceous of southern England
Authors: Ruffell A. 
Published: April 2008

Abstract

Three sequence boundaries (SB1, SB2 and SB3) are documented in the Upper Aptian
martinioides
to
jacobi
zones of the Lower Greensand Group of southern England. Correlation shows how folding affects only the strata of the lowest depositional sequence, indicating a discrete phase of tectonism in the
nutfieldiensis
zone/subzone (SB2). No similar tectonic deformation occurs at the sequence boundaries above or below. The regional features of this unconformity surface demonstrate that tectonically enhanced sequence boundaries may be discerned from those of eustatic/global tectonic origin. The tectonically enhanced sequence boundary (SB2) was initially interpreted as a transgressive surface at individual outcrops, but the regional pattern of truncation indicates that the transgressive surface is amalgamated onto a sequence boundary. Comparison of the geometry of each sequence on a regional (basin-wide) scale shows clearly the structural origin to truncation. Correlation of the three depositional sequences is made using their bounding surfaces, and the variable deposits of fuller’s earth bentonite, estuarine sand and lagoonal muds between SB1 and SB2 are resolved as time-equivalent facies deposited at the turn-around from sealevel lowstand to transgression. This correlation can be compared to that achieved by two conflicting ammonite zonal/subzonal schemes: the older biostratigraphy suggests diachroneity of the deformed lower sequence, whilst a new zonation shows this same sequence to be approximately synchronous.
Basal Wealden of Mupe Bay: a new model
Authors: Hesselbo Stephen P. 
Published: April 2008

Abstract
Angular stratal relationships associated with the Mupe Bay palaeo-oilseep in the Lower Cretaceous Wealden Group of South Dorset have previously been viewed as evidence of angular unconformity. An alternative (preferred) interpretation is that the succession represents rotational channel-bank collapse at the margin of a large Early Cretaceous fluvial channel. The new interpretation explains observed bedding-plane orientations and palaeocurrent directions.
The Mupe Bay oil seep: a detailed organic geochemical study of a controversial outcrop
Authors: Parfitt M. A. , Farrimond P. 
Published: April 2008

Abstract
The oil seep in an intraformational conglomerate at Mupe Bay has attracted much interest as providing possible evidence of oil generation in the Wessex Basin by the early Cretaceous (Wealden). Previous organic geochemical studies investigating whether oils of different maturity exist in the clasts and matrix of the conglomerate have been complicated by the effects of heavy biodegradation of the oil. In this work, we present detailed molecular organic geochemical data from a significantly larger suite of samples than has been previously studied. These have been screened using a multivariate statistical approach to identify those samples which have been least influenced by biodegradation. Conventional molecular maturity parameters applied to the subset of samples which have suffered no detectable modification to their biological marker (hopane and sterane) distributions indicate that the oil in the clasts is of exactly the same maturity as that in the matrix. However, this observation does not preclude two phases of staining, although it remains to be proven that the clasts contained oil at the time of their deposition.
Contractional and extensional structures in the transpressive ‘Big Bend’ of the San Andreas fault, southern California
Authors: Rust Derek 
Published: April 2008

Abstract

The San Andreas Big Bend is well known as a restraining bend producing transpressional conditions. However, field mapping in the southern part of the bend reveals a very wide (10 km) zone of active San Andreas faulting displaying a marked structural asymmetry on either side of the conspicuous central main fault trace, a result unexpected in the context of theoretical and model studies. The southern half of the fault zone is dominated by contraction and uplift in a strike-slip duplex, whereas the adjacent northern half displays a much greater number of probably older faults, particularly a succession of apparent P-shears as well as left-lateral probable R
1
-shears, producing extension and subsidence. It is proposed that these two halves of the fault zone represent mirror images of each other as a result of their positions relative to the most restraining section of the Big Bend, the shortening in the southern half being initiated as this section is approached, and the extension and complex faulting history of the northern half occurring as this terrain moves away from the most restraining section. These asymmetrical structural relationships, as well as their history of development, may be more generally applicable to major strike-slip fault zones in transpressional and, by analogy, transtensional situations. Clearly, the two halves of such fault zones are, structurally, remarkably discrete.
Salar Grande pull-apart basin, Atacama Fault System, northern Chile
Authors: Reijs Jurriaan , McClay Ken 
Published: April 2008

Abstract
The Salar Grande basin is a ‘poly-history’ strike-slip basin along the north-trending Atacama Fault System in northern Chile (21°S, 70°W). It exhibits a range of structures that indicate a complex evolution with multiple deformation styles. This paper presents a new interpretation of Salar Grande as a strike-slip pull-apart basin with three stages of evolution. In the first stage (Oligocene to Early Miocene), the basin opened as a sinistral strike-slip pull-apart structure at a left-stepping releasing jog of the Atacama Fault System. At the end of this stage, the basin had a rhomboidal geometry with dimensions of about 35 km length and 10 km width, bounded by a series of linked oblique-extensional basin-sidewall faults. The western sidewall faults linked to the northern fault strand of the Atacama Fault System whereas the eastern sidewall faults linked to the southern strand. The basin interior was a series of tilted fault blocks forming half-grabens. During the second stage (Oligocene to Early Miocene) a NNW-SSE basin short-cut fault developed, dissecting the basin with 6 km of sinistral offset. In the third stage (Pleistocene-Recent), NNW-SSE strike-slip faults were dextrally reactivated with displacements of up to 1 km. The understanding of field examples such as Salar Grande provides new insights into the geometries and evolution of complex multi-phase strike-slip terranes. The geometries recognized in Salar Grande compare well with analogue modelling studies of strike-slip fault systems.
Quaternary tectonics of the Pollino Ridge, Calabria-Lucania boundary, southern Italy
Authors: Schiattarella Marcello 
Published: April 2008

Abstract
The Pollino Ridge is a N120° trending morpho-structure, formed by Meso-Cenozoic carbonate rocks, that marks the boundary between Calabria and Lucania (southern Italy). It is bordered by Quaternary basins filled by both marine and continental sediments. A detailed geological survey and structural analysis in an area elongated perpendicular to the axis of the chain, ranging from the Morano Calabro basin to Mount Madonna del Pollino, was carried out. Data show that the entire mountain ridge and nearby Quaternary basins experienced several deformations in recent times, after the Mio-Pliocene thrust tectonics. Moreover, data are also consistent with numerous observations along the Calabria-Lucania boundary, from the Lauria Mountains to the Castrovillari basin. The present structure derives from reorganization of the pre-existing tectonogenetic configuration by Plio-Quaternary brittle tectonics. Mapping and kinematic analysis of a thrust along the northern (Lucanian) side of the Pollino Chain was performed for the first time. This thrust brings both the Cretaceous platform limestones and the Cerchiara Formation (lower Miocene age) over the Bifurto Formation (middle Miocene age). Low-angle transtensional faults along the southern (Calabrian) side were also mapped and analysed. These faults have created ‘younger-on-older’ type tectonic contacts. The present structure of the ridge is due to the effects of two different Quaternary tectonic stages. The first, lower Pleistocene in age, was characterized by strike-slip tectonics. It truncated ramp folds, producing new contractional and extensional features on the opposite sides of the carbonate ridge. The second stage occurred during middle Pleistocene times and was a purely extensional regime with a counter-Apenninic tensional axis, which reactivated the pre-existing structural pattern with different kinematics. However, both tectonic stages should be interpreted as a consequence of the continuous reorganization of the local stress fields as a result of a rotational field acting along the Pollino shear zone. The best explanation of this phenomenon seems to be a counter-clockwise block rotation of the carbonate ridge in an unchanging regional stress field.