bluuebunny/crossref_metadata_2025 huggingface dataset:
IBS Pannonian Basin project: a review of the main results and their bearings on hydrocarbon exploration
Authors: Horváth Frank , Tari Gábor
Published: April 2008

The IBS Pannonian Basin project presents a good example of fruitful joint activity between Hungarian and other European scientists, and beneficial co-operation of academia and the petroleum industry. This allowed us to achieve significant progress in the understanding of the structure, tectonic evolution, stratigraphic features and hydrocarbon generation in the Pannonian Basin.

The Pannonian region has been an integral part of the Alpine belt, and it reveals the complexity of orogenic evolution. Continental to oceanic rifting, followed by convergence, subduction and continental collision shaped the Palaeozoic-Mesozoic substrata of the region. Subsequently, two periods of basin formation (Late Cretaceous and Palaeogene) occurred, most probably in compressional setting. From the earliest Miocene large scale lateral displacement and block rotation took place in the internal domain of the orogen, together with the formation of the Pannonian Basin. This has been characterized by lithospheric extension, however, interrupted by compressional events. The modern Pannonian Basin is in an initial phase of positive structural inversion. All of these tectonic events had significant impacts on the formation and the economic value of the various petroleum systems in the area.
Late Neogene sedimentary facies and sequences in the Pannonian Basin, Hungary
Authors: Juhász E. , Phillips L. , Müller P. , Ricketts B. , Tóth-Makk Á. , Lantos M. , Kovács L. Ó.
Published: April 2008

Detailed sedimentological, facies and numerical cycle analysis, combined with magnetostratigraphy, have been made in a number of boreholes in the Pannonian Basin, in order to study the causes of relative water-level changes and the history of the basin subsidence.

Subsidence and infilling of the Pannonian Basin, which was an isolated lake at that time occurred mainly during the Late Miocene and Pliocene. The subsidence history was remarkably different in the individual sub-basins: early thermal subsidence was interrupted in the southern part of the basin, while high sedimentation rate and continuous subsidence was detected in the northeastern sub-basin.

Three regional unconformities were detected in the Late Neogene Pannonian Basin fill, which represent 0.5 and 7.5 Ma time spans corresponding to single and composite unconformities. Consequently two main sequences build up the Late Neogene Pannonian Basin fill: a Late Miocene and a Pliocene one. Within the Late Miocene sequence there are smaller sedimentary cycles most probably corresponding to climatically driven relative lake-level changes in the Milankovitch frequency band. Considering the periods, the estimated values for precession and eccentricity in this study (19 and 370 ka) are close to the usually cited ones. In the case of obliquity the calculated period (71 ka) slightly deviates from the generally accepted number. Based on the relative amplitudes of oscillations, precession (sixth order) and obliquity (fifth order) cycles had the most significant impact on the sedimentation. Eccentricity caused cycles (fourth order) are poorly detectable in the sediments. The longer term (third order) cycles had very slight influence on the sedimentation pattern.

Progradation, recorded in the Late Miocene sequence, correlates poorly in time within the basin. The dominant controls of this process probably were changes of basin subsidence rate and the very high sedimentation rate. The slow, upward trend of silt and sand bed thickness as well as that of the grain size also reflects the local progradation.
The present-day tectonics of the Aegean as deduced from seismicity
Authors: Hatzfeld Denis
Published: April 2008

We present a review of the seismicity and focal mechanisms for the Aegean (historical, teleseismically and microseismically computed), which we compared with the recent active faults. A very consistent trend in the T-axes within the Aegean across blocks of different size and orientation suggests that the surface tectonics of the Aegean is controlled by the deformation of the lithosphere as a whole. Some recently active faults (mostly the NW-SE-striking faults that are located west of the Aegean sea) are not associated with seismicity, some seismicity is associated with new E-W-striking faults of modest displacement that are mostly seen in continental Greece. We suggest that, due to the important amount of internal deformation of the Aegean lithosphere and the inferred rotations, the localization of the deformation changes with time and a precise timing of the recent faults activity is necessary to correlate with present-day deformation. We also suggest that, for continental crust, the work to create new fault that strike perpendicular to the main strain direction (as deduced from focal mechanisms and GPS measurements) is less than the work to reactivate faults that strike obliquely to the strain direction. We propose that a diffuse system of normal faults or grabens starts to develop, parallel to the Gulf of Corinth, and links the western termination of the North Aegean Trough to the northern end of the Kefallinia fault.
On the origin of west-directed subduction zones and applications to the western Mediterranean
Authors: Doglioni C. , Gueguen E. , Harabaglia P. , Mongelli F.
Published: April 2008

West-directed subduction zones show east-verging arcs of 1500–3000 km. They are usually younger than 50 Ma and are characterized by a frontal accretionary wedge and a back-arc basin propagating together toward the east. The accretionary wedge scrapes off superficial layers of the downgoing plate (thin-skinned tectonics) whereas the back-arc extension cross-cuts the entire subduction hanging wall (thick-skinned tectonics). The slab of this type of subduction is steep to vertical and the hanging wall of the subduction has a mean elevation of 1000 m below sea level. Trenches and foredeeps are the deepest basins of the Earth and the mean depth is of 5000 m below sea level. West-directed subduction occurs both in case of the highest E-W convergence rates among plates (e.g. W Pacific examples) and no or very low convergence (e.g. Carpathians). Following Atlantic W-directed subduction examples, the W-directed subductions seem to develop along the back-thrust belt of former E-directed subduction zones, where oceanic lithosphere occur in the foreland to the east with the narrowing of the American continents. This could be applied to the onset of the Apennines subduction along the back-thrust belt of the Alpine-Betic orogen where Tethys oceanic crust was present. The Alpine orogen was stretched and scattered in the Apennines back-arc basin. The back-arc extension is internally punctuated by necks (sub-basins) and boudins (horsts of continental lithosphere). Asymmetric extension in the back-arc basin appears controlled by differential drag between the eastward mantle flow and the overlying passively transported crustal remnants. Compression in the accretionary prism may be interpreted as the superficial expression of the shear occurring between the downgoing lithosphere and the horizontally moving mantle which compensates the slab roll-back. The area of the Apennines appears lower than the area of the sedimentary cover before subduction: this favours the idea that not significant crustal slices have been involved in the Apenninic accretionary prism, and the basement thrust sheets included in the western part of the belt are mainly relicts of the Alpine-Betic orogen.
Overview of partitioning and fate of contaminants: retention, retardation and regulatory requirements
Authors: Yong Raymond N.
Published: April 2008

This overview study examines the principal interactions between contaminants and soil fractions responsible for contaminant partitioning, with the aim of developing a further understanding of retardation and retention processes during contaminant transport. The defining mechanisms for sorption and desorption of contaminants are generally known for many types of contaminants in interaction with specific soil fractions. However, contaminant accumulation in soil-engineered barriers or soil substrate material needs to be addressed in terms of contaminant retention or contaminant retardation as a contaminant attenuation process. This is necessary if regulatory requirements regarding
natural attenuation capabilities
are to be fulfilled. The combined processes leading to partitioning of contaminants in complex mixtures of contaminants and soil fractions have yet to be fully defined and understood. However, sufficient information exists concerning chemical and biologically mediated mass transfer to permit one to appreciate the need for distinguishing between irreversible sorption and temporary sorption processes. Failure to properly realize this can make the natural attenuation concept for clay barriers a ‘disaster waiting to happen’.
The mineralogy and geochemistry of cement/rock reactions: high-resolution studies of experimental and analogue materials
Authors: Hodgkinson Emily S. , Hughes Colin R.
Published: April 2008

Cements are commonly used to engineer the environment around waste disposal sites. As groundwaters move through these sites, cement gradually dissolves and a reactive ‘hyperalkaline plume’ forms downstream. Published experimental and modelling studies of cement/rock reactions suggest that host-rock mineralogy will dissolve and be replaced initially by high-volume calcium silicate hydrate gels, and later by zeolites. Results of mineral/alkali experiments are presented. Examination of the reaction products, at the high analytical resolution afforded by ATEM, show new disordered phases which are structurally related to calcium silicate hydrates but are highly aluminous (relative to the published results of previous work). A review of archaeological analogue studies shows that old cement pastes easily become carbonated in the presence of CO
2
or carbonate waters. If protected from carbonation, however, cement gels can survive unchanged for thousands of years. New results of an ATEM examination of 1700 year-old Roman mortar from Hadrian’s Wall confirm that cement gels remain poorly ordered and reveal an aluminous CSH gel phase to be the chief product of mortar/dolerite reaction. These findings are discussed in the context of barrier engineering.
Chemical containment of mine waste
Authors: Bowell R. J. , Williams K. P. , Connelly R. J. , Sadler P. J. K. , Dodds J. E.
Published: April 2008

The safe disposal of material considered hazardous is a natural part of good housekeeping for any industrial development. This is particularly so for the mining industry which has historically not always been so well managed in this aspect and as such has a high political profile today. Typical problems associated with mineral processing and mine waste are:

•

poor water quality, through the release of sulphate, acidic waters, metals, metalloids and other undesirable substances

•

poor air quality, through the release of mineral dust and gases such as SO
2
, As
2
O
3
, Hg vapour and CO
2
amongst others

•

contamination of land by the above with elevated levels of metals, sulphate and metalloids.

When the impact has been allowed to occur, control can be difficult and remediation costly. Consequently great efforts have been made over the last ten to fifteen years in understanding the nature of the potential pollutants, their pathways, environmental tolerances and solutions to their impact either by ‘dilute and disperse’ methods, recovery or containment.

In discussing the chemical containment of mining waste three broad categories can be defined: source control, migration control and dispersion control. Source control refers to measures employed to prevent the release of contaminants from solid phases. Migration controls restrict the interaction between environmental agents (principally water and humid air) and the deleterious element solid hosts. Dispersion control involves the collection and treatment of contaminated material such that they can be dispersed into the environment without significant impact. This last option, although the most common practice is also the most expensive and also may be required long term.
Toxic metal mobility and retention at industrially contaminated sites
Authors: West L. Jared , Stewart D. I. , Duxbury J. R. , Johnston S. Richard
Published: April 2008

This paper is concerned with industrial sites contaminated with heavy metals, specifically cadmium (Cd), chromium (Cr), arsenic (As), mercury (Hg), lead (Pb), copper (Cu), nickel (Ni) and zinc (Zn), as these are the heavy metal contaminants that cause most concern. It is intended as a source of information to aid engineers and geologists concerned with risk assessment and remediation at such sites. The risks from heavy metals depend strongly on their chemical form, and therefore literature on the chemical forms of metals released at industrial sites is reviewed. Changes in the chemical forms of heavy metals resulting from environmental interactions are discussed, and methods for determining metal chemistry (leaching tests, chemical extractions, direct methods) are outlined. The paper concludes with a case study where the chemical forms of heavy metals at a former metal smelting and vehicle scrapyard site are investigated using a scanning electron microscope with energy dispersive X-ray spectroscopy and selective sequential chemical extractions. The case study showed that Zn is currently mobile at the site whereas Pb, Cu, or Ni are not, and this highlights the importance of adopting a multidisciplinary approach to investigating toxic metal mobility and retention.
A probabilistic risk assessment methodology for landfills, with particular reference to the representation of chemical containment
Authors: Plimmer B. R. , Pringle A. B. , Moncaster S. J.
Published: April 2008

In Waste Management Paper 26B, the Department of the Environment advocate the use of risk assessment in the design of waste disposal sites, such that the potential impact of the facility on specified receptors may be identified and minimized. In this paper the tool currently used by the regulatory authorities to assess the risk to groundwater (LandSim) is examined, paying particular attention to the treatment of chemical containment. A case study is presented demonstrating two different approaches to the modelling of the potential attenuation of ammonia afforded by the geosphere.
A pre-development turbidite reservoir evaluation using FMS electrical images
Authors: Rider Malcolm , Goodall Tim , Dodson Tim
Published: April 2008

FMS (Formation MicroScanner) electrical images in a single well from a familiar, deep marine North Sea Palaeogene section are illustrated. More than 900 m of good quality images were acquired through an interval from the Palaeocene Ekofisk Formation to the Eocene Grid Formation in a well from the centre of the South Viking Graben, Norwegian sector. The information that was obtained from these images is illustrated and discussed in terms of lithology, sedimentary structures, stratigraphy and petrophysics. The information on this deep marine, mainly gravity deposit succession, is considerably enhanced using image interpretation. Lithological information includes an improved net-to-gross ratio and an understanding of lithological heterogeneities. Sedimentary structure information includes the geometrical and lithological characterization of slumped intervals and a detailed description of evolving gravity deposit sequences. In terms of stratigraphy, illustrative images are shown of the Balder, Lista and Sele Formations. Some of the key surfaces of the Palaeogene interval, used for correlation and sequence stratigraphy, are shown in detail, especially the surface at the base of the Balder Formation and the boundary between the Lista and Sele Formations. The effect of hydrocarbons on the images is illustrated and used qualitatively in petrophysical terms to define the hydrocarbon-water contact.
Petrological and geochemical evidence for the tectonic affinity of the (?)Ordovician Poortown Basic Intrusive Complex, Isle of Man
Authors: Power G. M. , Crowley S. F.
Published: April 2008

The rocks of the Poortown Quarry, 3 km east of Peel, Isle of Man, are shown to comprise a complex series of sills of pyroxene-rich dolerite, plagioclase-rich dolerite and plagioclase-phyric andesite intruded into Manx Group deep-water marine sedimentary rocks of Arenig age. They have suffered early Devonian deformation and greenschist facies metamorphism, together with later alteration and faulting. The pyroxene-rich dolerite has the composition of a Mg-rich basalt relatively enriched in Fe, Cr and Ni. It contains up to 60% augite and is likely to have been produced by fractionation in a high-level magma chamber before intrusion into its present position. Some of the pyroxene grains have more primitive (higher Mg, Cr and lower Ti), partly resorbed cores which supports a multi-stage history for this magma.

The sills cover a range of compositions from Mg-rich basalt to calc-alkaline basaltic andesite and the geochemistry of the more immobile elements suggests a calc-alkaline volcanic arc origin in an active continental margin environment. Although the age of the Poortown Complex is poorly constrained, a tentative comparison is made with the lower part of the Borrowdale Volcanic Group of the English Lake District.
Deep sea tephra from Nisyros Island, eastern Aegean Sea, Greece
Authors: Hardiman J. C.
Published: April 2008

Isopach maps have been constructed onland for the proximal deposits of the caldera-forming pyroclastic eruptions from the Quaternary volcano Nisyros and are augmented by a newly recognized Nisyros ash layer in the SE Aegean. The Lower Pumice eruption had a NE-SW dispersal direction with onland isopachs from 1–7m thickness and a vent position on the eastern side of the ancestral cone. A 3mm thick layer of Lower Pumice ash is found 75km away to the SW of the island at a depth of 133cm. This layer yields a Lower Pumice age estimate of 35ka. The Upper Pumice had a NNE dispersal direction with onland isopachs from 1–7m thickness and a vent position on the northern side of the island. No Upper Pumice ash has been found in the core record. Preliminary volume estimates derived from the isopach maps and the lack of regionally correlatable Nisyros ash deposits in the Aegean core record suggest that the caldera formation on the island was incremental and tephrostratigraphic markers suggest it occurred between
c.
35 and 31 ka ago.
Regional warming of the lower atmosphere in the wake of volcanic eruptions: the role of the Laki fissure eruption in the hot summer of 1783
Authors: Grattan John , Sadler Jon
Published: April 2008

A suggestion is made that the gases emitted in the Laki fissure eruption in the summer of 1783 contributed to the high surface-air temperatures recorded in many parts of Europe. This paper presents European documentary and instrumental evidence which suggests that, during the initial stages of the eruption of the Laki fissure in June and July 1783, intense localized warming of the lower atmosphere occurred in many parts of Europe. This phenomenon is examined in detail and a hypothesis advanced that, under specifically defined conditions, volcanic gases may lead to warming of the lower atmosphere.
Environmental and social responses in Europe to the 1783 eruption of the Laki fissure volcano in Iceland: a consideration of contemporary documentary evidence
Authors: Brayshay Mark , Grattan John
Published: April 2008

A detailed examination of contemporary documentary evidence, including letters, diaries, historical accounts and newspaper reports, reveals the dramatic effect on the weather across the whole of western Europe of the eruption of the Laki volcanic fissure in Iceland in 1783. Extreme heat, dry sulphurous fogs, chemical pollution, and tremendous storms of thunder, lightning and hail were reported from northern Scotland to Sicily. Vegetation was defoliated, crops were destroyed, livestock were killed and property was damaged. There were also direct and indirect human casualties. The unusual conditions engendered considerable fear as well as an appeal to science for a rational explanation. Volcanic eruptions and earthquakes in southern Italy and Iceland were blamed as the cause.
Human adjustments and social vulnerability to volcanic hazards: the case of Furnas Volcano, São Miguel, Açores
Authors: Chester David K. , Dibben Christopher , Coutinho Rui , Duncan Angus M. , Cole Paul D. , Guest John E. , Baxter Peter J.
Published: April 2008

Following a review of recent developments by social theorists, concerned with the policy and practice of natural hazard reduction it is argued that neither the so-called
dominant
nor the
radical
perspectives, are sufficient on their own to answer the questions now being addressed by applied volcanologists during the International Decade for Natural Disaster Reduction. In order to make useful recommendations to policy-makers, which are both reliable assessments of eruption risk and at the same time sensitive to probable interactions of future eruptions with the physical environment of the study region and its peoples, a conflation of traditional hazard analysis and vulnerability analysis is required.

This view is tested by means of a case study of evacuation planning at Furnas Volcano in the Açores. As well as supporting the argument from theory, this example leads to the proposition that research on evacuation planning and civil defence should proceed in an ordered sequence. First hazard analysis (i.e. hazard mapping) should be carried out in the traditional manner. Next possible interactions with the physical environment should be specified and a preliminary plan of evacuation routes drawn up. Before detailed recommendations about the logistics of evacuation are made, however, it is vital that such factors as the demographic, socio/economic and cultural/behavioural characteristics of the population at risk are fully considered.
Pre-Devonian landscape of the Baltic Oil-Shale Basin, NW of the Russian Platform
Authors: Puura Väino , Vaher Rein , Tuuling Igor
Published: April 2008

The erosional relief of Ordovician and Silurian deposits in Estonia was developed during the continental period in late Silurian and early-middle Devonian times. The uplift of the area and marine regression were induced by compressional tectonics in the continental interior related to the closure of the Iapetus and Tornqvist Oceans.

In the northern part of the Baltic sedimentary basin (Estonia), on the gentle southerly dipping slope between the Fennoscandian Shield (Finland) and Baltic Syneclise (Latvia), a pre-Devonian, slightly rugged erosional relief with few cuesta was developed. The pre-Devonian erosional landforms — hills, depressions and escarpments reaching 150 m in height — were probably buried under the Devonian deposits and then partly re-exposed by pre-Quaternary erosion. These landforms are described in detail using data from several thousands of cores drilled in the course of oil-shale and phosphorite exploration and mining.
The application of palaeolandsurface analysis to the study of recent tectonics in central Italy
Authors: Basili Roberto , Galadini Fabrizio , Messina Paolo
Published: April 2008

The analysis of remnant landsurfaces was carried out on the ranges surrounding three intermontane basins located in the central and southern Apennines. All three basins developed during the Pliocene and Quaternary, but each had a different geological, geomor-phological and structural setting. Landsurfaces taken into account were those which aided in the identification of strath terraces situated on the walls of the basins. Recognition and comparison of terrace sequences aided the evaluation of the tectonic behaviour of each area by identifying sectors with differential vertical movements and by assessing the activity of the faults that caused them. The analysis of individual cases also provided useful information on fault activity that could help in devising structural schemes related to active tectonics.
Preliminary observations on the geomorphic evolution of the Guide Basin, Qinghai Province, China: implications for the uplift of the northeast margin of the Tibetan Plateau
Authors: Fothergill P. A. , Ma H.
Published: April 2008

Landform development in the Guide Basin has been influenced by the late Tertiary and Quaternary tectonic evolution of northeast Tibet. In the south of the Guide Basin, the remnants of three palaeosurfaces are preserved on top of flat-topped landforms. The two highest palaeosurfaces are separated by faults, which are thought to be extensional. Normal faulting may have begun in the middle-late Pleistocene, possibly indicating that the Guide Basin had reached its maximum elevation by this time. Yellow River drainage development within the Guide Basin may also have occurred in middle-late Pleistocene times, following the onset of extensional faulting.
Flood behaviour of the Burdekin River, tropical north Queensland, Australia
Authors: Alexander Jan , Fielding Chris R. , Pocock Geoff D.
Published: April 2008

Strongly seasonal rainfall in north Queensland, Australia, causes extremely variable fluvial discharge, and tropical cyclones commonly produce high-magnitude, short-duration floods. In the Burdekin River catchment (129 500 km
2
of eastern Queensland), rapid runoff and channel floodplain configuration lead to very fast flood-wave speeds (up to 4.34 m s
−1
calculated). The large catchment and varying tropical cyclone paths result in extreme variations in flood history at different sites. Changes in channel conditions (bed elevation, vegetation, bedforms, sediment surface character) in successive events, combined with complex rainfall patterns and highly unsteady flow, make flood estimates extremely difficult. Because of the short duration of flow events and very rapid rate of change in discharge during individual events, sediment transport rate, bedforms, and bed elevation change continuously. For most of the year the channel is occupied by an underfit stream, but this small perennial stream does not significantly rework the deposits or change channel form before the next major discharge event. Consequently, there is little channel form recovery between major discharge events. Successive events have very variable size and consequently the bedforms and channel morphology are normally out of equilibrium with the flow, and record the result of the most recent major events. High-magnitude floods transport coarse sediment onto the floodplain and the short duration of flooding and rapid runoff results in relatively low preservation of mud in the channel or overbank environment. The Holocene flood deposits include thick, coarse sand and medium sand units and generally thin, fine-grained units.
Potential for floodplain rehabilitation based on historical maps and present-day processes along the River Rhine, The Netherlands
Authors: Schoor Margriet M. , Wolfert Henk P. , Maas Gilbert J. , Middelkoop Hans , Lambeek Jurriaan J. P.
Published: April 2008

For the purpose of restoration, a process-based geomorphological and ecological classification of rivers and river reaches has been developed to help identify both past and present-day geomorphological processes along lower branches of the Rhine. Historical maps are used to analyse floodplain development since 1600. The series of maps shows development and erosion of bars and floodplains, and land use reflects both vegetation and geomorphological patterns and indicates that the ecological succession was strongly related to geomorphology. Historical measurements (early 19th century) of the water depth and water levels are used to derive historical river profiles and water duration curves. Present-day hydraulic parameters were calculated which show that they are not related to the geomorphological patterns in floodplains. Changes in the geomorphological activity of the river are strongly related to changes of the width-depth ratio of the main channel. Potentials for bar and levee development are therefore based on differences between the width-depth ratio of the Rhine branches.
A mechanism for the formation of overconsolidated horizons within estuarine floodplain alluvium: implications for the interpretation of Holocene sea-level curves
Authors: Crooks Stephen
Published: April 2008

The stratigraphic sequence held in accumulating estuarine floodplain alluvium provides a detailed record of past sea-level movement. However, contrasting Holocene sea-level curves have been derived for two basins in southern Britain. The sea-level curve of the Thames Estuary Basin describes up to five possible regressive cycles superimposed onto a long-term transgressive trend. In the Severn Estuary no regressive cycles have been, as yet, identified. These differences in interpretation are, in part, due to the identification of ‘overconsolidated’ horizons, found within Essex alluvium, which have been argued to represent prolonged periods of desiccation. No such horizons have been found in the Severn Estuary. By examining the sedimentological and geotechnical characteristics of a number of active, land-claimed and regenerated saltmarshes from these regions, this paper identifies the mechanism for the formation of overconsolidated horizons to be geochemically controlled and regionally variable. The presence of suitable quantities of detrital calcium carbonate is important in preventing the formation of these horizons. The carbonate-deficient alluvium in the Thames Estuary region appears to be particularly sensitive to the effects of a lowered saline water table, inducing the deflocculation of clays and formation of dense horizons. By contrast, the sediments in the carbonate-bearing alluvium of the Severn Estuary are insensitive to pore-water salinity changes so an absence of overconsolidated horizons in the floodplain alluvium does not preclude past sea-level falls.
The application of microgravity in industrial archaeology: an example from the Williamson tunnels, Edge Hill, Liverpool
Authors: Cuss Robert J. , Styles Peter
Published: April 2008

This article presents the results of a high-resolution microgravity survey which was successful in delineating the 150-year old Williamson tunnels beneath inner-city Liverpool, England. The tunnels, which date from the Napoleonic Wars, lie at depths of
c.
5 to 15 metres, and are poorly mapped because of several phases of later development and subsequent dereliction. The ‘brown-field’ nature of this site created substantial noise signals which required the application of careful terrain corrections and second derivative and Euler deconvolution methods to isolate and identify the tunnel signatures. Successful delineation was only possible because of a comprehensive initial desk study and prior modelling, which assessed the likely depths and conditions of the impassable tunnels and allowed appropriate techniques and survey parameters to be determined.
The determination of bloomery furnace mass balance and efficiency
Authors: Thomas Gary R. , Young Timothy P.
Published: April 2008

A technique for the graphical solution of the ore:furnace lining:fuel ash mixture in the melt and the yield of the reaction during bloomery iron smelting is presented. The technique focuses on the so-called immobile elements, particularly the rare earth elements, but employs a wide range of elements. Previous attempts to determine ore sources from iron slag chemistry have generally examined the major and minor elements of the slags, but are complicated both by the significant, but variable, concentrations of some of these elements in charcoal and by the mobility of some major elements during weathering. The new approach has been developed to aid the provenancing of slags from the smelting of iron-ores from the Bristol Channel Orefield, which is characterized by high purity goethite/haematite ores with extremely low trace element concentrations. It is thus particularly important to understand the involvement of furnace lining in the melt, for this material will have the dominant contribution to the trace element chemistry. The mass balance approach is illustrated using smelting slags, furnace lining and roasted ore fragments from the Roman iron making town of
Ariconium
(near Ross-on-Wye, Herefordshire) and a good degree of compatibility of these materials is demonstrated.
Some time-space relationships for crustal melting and granitic intrusion at various depths
Authors: Thompson Alan Bruce
Published: April 2008

Crustal melting occurs at the higher grades of metamorphism. Migmatites reflect crustal anatexis without necessary additional heat supply. Granites usually result from crustal melting resulting from ‘hot’ geotherms, or reflect an external heat supply.

The commonest mechanisms of crustal melting are: (i) decompression of crust thickened into mantle in convergent orogens; (ii) asthenosphere upwelled beneth the crust in extensional orogens; (iii) massive invasion or underplating of crust by mantle magma generated by mantle decompression. This paper considers some of the processes governing timescales and lengthscales of these various magmatic events with particular view to determining the intensity and duration of crustal melting, and relationships between the rates of melt extraction, ascent and emplacement.
Emplacement of the Joshua Flat-Beer Creek Pluton (White Inyo Mountains, California): a story of multiple material transfer processes
Authors: Dietl Carlo
Published: April 2008

The Joshua Flat-Beer Creek Pluton (JBP) in the White Inyo Mountains, California, is part of the Inyo batholith, which intruded a Neoproterozoic to Lower Cambrian metasedimentary sequence at about 180–160 Ma ago. Contact metamorphism around the JBP reached hornblende-hornfels- to lower amphibolite-facies conditions. The intrusion consists of three distinct phases. Field relations suggest an intrusion sequence Marble Canyon Diorite-Joshua Flat Monzonite-Beer Creek Granodiorite as nested diapirs. In the Marble Canyon Diorite as well as the Joshua Flat Monzonite the subsequent intrusions led to brecciation and stoping, but also to mingling and mixing between the Joshua Flat Monzonite and the Beer Creek Granodiorite. Fabrics in the contact aureole document several emplacement mechanisms such as stoping and dyking, ductile downward flow, partial melting and magma chamber expansion. The relative importance of the different emplacement mechanisms through time is as follows: the Marble Canyon Diorite probably intruded as dyke/sill, whereas stoping and dyking, ductile downward flow together with assimilation acted during the emplacement of the Joshua Flat Monzonite. Magma chamber expansion represents only the latest stage of intrusion during the emplacement of the Beer Creek Granodiorite into the already existing magma chamber of the JBP. AMS, quartz
c
-axis and strain measurements support the field observations.
Indentation of volcanic edifices by the ascending magma
Authors: Merle Olivier , Donnadieu Franck
Published: April 2008

The process by which magma ascends into and deforms a volcanic edifice is studied by analogue modelling. A control experiment is conducted with a wooden piston moving vertically into a sand cone. This reveals a well-defined fault pattern that makes it possible to draw the main compressive stress trajectory within the cone during the ascent of the piston. This makes it possible to show that the deformational process is that of indentation of the cone by the rigid piston. Experiments with an indenter that is viscous, as in nature, show that the motion of the viscous body is controlled by the first fault created in the cone. This fault serves as a structural guide, making the viscous body deviate from the vertical and resulting in deformation of the flank of the cone, which bulges out. Other major shear faults that were observed in the control experiment are then inhibited and do not form. This result emphasizes that the structural evolution of an indentation process within a brittle cone and at low rate depends on the rheology of the indenter.
Pluton emplacement in the Northern Tyrrhenian area, Italy
Authors: Rossetti F. , Faccenna C. , Acocella V. , Funiciello R. , Jolivet L. , Salvini F.
Published: April 2008

The post-orogenic extensional processes that affected the inner sector of the Northern Apennine orogenic wedge (i.e. the Northern Tyrrhenian region) were accompanied by the emplacement of chiefly anatectic intrusive rocks of Late Miocene to Mid-Pleistocene age. In this paper, we compare geological and structural data from Messinian-Pliocene monzogranitic intrusions located both offshore (Monte Capanne, Porto Azzurro, Montecristo and Giglio) and onshore (Gavorrano and Botro ai Marmi) in the Northern Tyrrhenian region to constrain modes of pluton emplacement. Offshore, eastward non-coaxial extensional shear zones active both in ductile and brittle conditions accompanied the emplacement of the monzogranitic intrusions, and accommodated extension oriented E-W to WNW-ESE. Onshore, N-S dextral strike-slip faulting was active both during and after the late stage of emplacement of both Botro ai Marmi and Gavorrano plutons, and controlled their rise in coincidence with releasing bends. In our interpretation, the N-S, Late Miocene-Pliocene strike-slip faulting constitutes a secondary shear feature in a context of generalized post-orogenic extension, accommodating in the brittle upper crust the non-coaxial ductile extension in the lower crust. In this framework, N-S strike-slip faults localized the rise of early anatectic magma, generated during regional post-orogenic extension and residing at the base of the extending crust.
Recrystallization salt fabric in a shear zone (Cardona diapir, southern Pyrenees, Spain)
Authors: Miralles L. , Sans M. , Pueyo J. J. , Santanach P.
Published: April 2008

In the southern Pyrenees foreland, the Cardona salt diapir has a 250 m high stem and a small bulb, which is partially exposed. The internal structure of the diapir consists of a main sheath fold divided by a shear zone. This shear zone crosses two salt units with different initial properties. In this paper, a qualitative analysis of the fabric both units crossed by the shear zone and a 3D quantitative morphological and textural analysis of the unit with small grain size were carried out. In this unit, the fabric is characterized by a grain size similar to that of the initial fabric, disappearance of primary structures, a poor grain orientation with the long axis statistically at 20° of the shear boundary, and a strong {100} crystallographic preferred orientation. The unit composed of coarser grains shows a disappearance of primary structures. The fabric changes in both units and the strong decrease in water content during deformation suggest that fluid-assisted synkinematic recrystallization was dominant. The different behaviour of the two studied units on shear deformation also suggests that the initial grain size and water content were the main factors controlling fabric changes.
Holocene sediment storage in the Humber Estuary
Authors: Rees J. G. , Ridgway J. , Ellis S. , Knox R. W. O’B. , Newsham R. , Parkes A.
Published: April 2008

In order to determine the processes that have governed the accumulation and erosion of sediments in the Humber Estuary (English North Sea coast) through the Holocene, the character, volume and source of sediments were studied. Eight sediment suites were identified on the basis of chemostratigraphy, lithostratigraphy and mineralogy. The locally sourced, freshwater, Basal Suite is overlain by the Newland and Butterwick Suites, deposited between
c.
8 and 7.4 cal. ka
bp
in brackish environments behind a morainic barrier at St Andrew’s Dock, Hull. These are overlain by the largely marine, saltmarsh sediments of the Garthorpe Suite, which in turn are overlain, with erosional contact, by the channel sandflat and mudflat deposits of the Saltend, Sunk Island and Skeffling Suites. Most of the Saltend Suite is likely to have been deposited since
c.
4 ka ago, whilst the Sunk Island and Skeffling Suites are likely to have been deposited since Medieval times and from the late eighteenth century onwards, respectively, as indicated by their concentrations of anthropogenic metals. On the coast, the Spurn Suite consists of sediments, associated with a spit system, which are almost entirely marine in origin. The suites show a progressive increase in marine influence; sediments of the oldest suite being entirely from the terrestrial catchment, those of the younger suites from erosion of the North Sea floor and coast. The relationships between suites show that during the last 4 ka the geomorphological evolution of the estuary has been marked by widespread erosion episodes that have led to the partial removal or redistribution of earlier deposits. By modelling the volumes of the suites it can be shown that, of the total volume of the estuarine fill (9.6 km
3
), over half is likely to have been deposited during this period.
Origin, abundance and storage of organic carbon and sulphur in the Holocene Humber Estuary: emphasizing human impact on storage changes
Authors: Andrews J. E. , Samways G. , Dennis P. F. , Maher B. A.
Published: April 2008

An organic carbon (C
org
) and sulphur (S) storage inventory for Holocene sediments in the Humber Estuary is established; sources of organic matter and their variation over time are identified, and with chronological control, the importance of estuarine sediments as C
org
and S stores is demonstrated. Humber Holocene sediments are grouped into seven widespread environmental facies with statistically significant geochemical data sets: (1)
oak-hazel fenwood
(OHF); (2)
alder carr
(AC), appearing as peats in core; (3)
river channel muds or sands
(Rcm/s); (4)
high saltmarsh
(HSM); (5)
low saltmarsh
(LSM); (6)
intertidal mudflat
(ITMF); and (7) a
sandy
facies (S). Carbon, nitrogen and sulphur (CNS) abundances show that these facies have diagnostic geochemical signatures and δ
13
C values for bulk organic matter exhibit a range of average values: −28‰ (terrestrial peats), −27‰ (HSM), and −24.5‰ (ITMF) reflecting the up core transition from terrestrial peats through saltmarshes to more open marine mudflat environments as regional sea-level rose. Chronology and average sedimentation rates are partly constrained by radiocarbon dates; palaeomagnetic techniques helped define discrete sediment packages and discontinuities (time gaps). Although the Humber Holocene sediment record is not continuous, long-term sedimentation rates (about 1 mm a
−1
) show that sediment accretion kept pace with regional sea-level rise between 6 and 2 cal. ka
BP
. This sedimentation rate, combined with core evidence to allow a geographic reconstruction of the palaeo-Humber (3–2cal. ka
BP
), is used to calculate storage values for C
org
and S in the various environments of the palaeo-Humber. Comparison of the C
org
and S sedimentation and storage terms for the palaeo-Humber with modern values highlights the impacts of reclamation and commercial/urban development in the estuary in the last 300 years. OHF and AC peats, which were the largest C
org
and S stores in the palaeo-estuary, are now absent (reclaimed), while saltmarshes are no longer widespread. Conservative calculations show a net decrease in C
org
deposition from about 3.2 × 10
5
tonne in the palaeo-estuary to no more than 2.5 × 10
3
tonne today, a >99% reduction in potential C
org
storage capacity. The total modern yearly S deposition is approximately 2% of its value 2ka ago. Removal of saltmarsh and associated brackish-freshwater wetland suggests that suspended sediment and associated C
org
and S are currently bypassing former (Holocene) storage areas and may be impacting North Sea biogeochemical cycling.
Sediment provenance and flux in the Tees Estuary: the record from the Late Devensian to the present
Authors: Plater A. J. , Ridgway J. , Rayner B. , Shennan I. , Horton B. P. , Haworth E. Y. , Wright M. R. , Rutherford M. M. , Wintle A. G.
Published: April 2008

The influences of sea-level, climate, human activity and coastal morphology on post-glacial sediment flux and deposition in the Tees Estuary were considered in a multidisciplinary investigation of the Late Pleistocene and Holocene sedimentary record. The following tripartite division was identified using a combination of lithostratigraphic and geochemical data: a Late Glacial laminated clay providing evidence of a former proglacial lake and a proxy record of climate change; an early-mid-Holocene intercalated sequence of tidal silts and clays and peats; and a late Holocene succession characterized by increasing evidence of human activity and metal contamination. Sea-level change has been identified as the main control on sedimentation
via
decelerating sea-level rise and changing tidal dynamics between
c.
8 and 3 ka
bp
. Climate controlled the sequence of rhythmite thickness in the Late Glacial clays, whilst increased wetness after
c.
3 ka
bp
may have encouraged terrestrial sediment influx. Enhanced sediment supply to the coastal zone can also be attributed to increasing human activity in the catchment from the Bronze Age onward, first as a consequence of clearance, and subsequently as a result of mining and industrial expansion. Fine-grained sediment flux has almost exclusively been from the Tees catchment to the coast, extending offshore during rebound-induced collapse and erosion of the Late Glacial lake basin. The only notable onshore sediment flux has been the deposition of marine sands in the outer estuary between
c.
6.5 and 3.5 ka
bp
.
Sedimentary evolution of the north Norfolk barrier coastline in the context of Holocene sea-level change
Authors: Andrews J. E. , Boomer I. , Bailiff I. , Balson P. , Bristow C. , Chroston P. N. , Funnell B. M. , Harwood G. M. , Jones R. , Maher B. A. , Shimmield G. B.
Published: April 2008

Holocene sediments of the north Norfolk coast (NNC) between Weybourne and Hunstanton have been studied using geophysical, sedimentological, biofacial and dating techniques. New cores and refraction seismic data have defined the topography of the pre-Holocene surface and show that the NNC sediment prism is underlain by an east-west trending Quaternary trough, probably a palaeo-river-valley. The age of the Holocene fill has been dated using radiocarbon and luminescence dates, while sedimentation rates were constrained by, and compared with, modern rates using radionuclide data. The Holocene sediments are divided into a sandy-barrier lithofacies association (LFA), and a muddy-silty-peat back-barrier LFA. The oldest Holocene sediments are peats, formed on an undulating till surface. These peats were forming by 11-10 cal. ka
bp
and continued to form until at least 7 cal. ka
bp
in a number of places. As Holocene sea-level rose, marine mudflat and saltmarsh environments began to form between 7 and 6 cal. ka
bp
east of Holkham and around 6 cal. ka
bp
or younger west of Holkham. A marked erosion surface between the barrier and back-barrier LFA in the Holkham to Burnham Overy area is imperfectly dated at <3 cal. ka
bp
, but suggests the sediment prism has thinned by about 3 km over 6 to
c
. 3cal. ka
bp
. This surface probably records the westward progress of laterally migrating tidal channels that caused back-barrier sediment erosion, along with shoreface processes, as sea-level rose. Small-scale regressive and transgressive saltmarsh sequences occur at different elevations along strike but cannot be correlated, suggesting that the control on saltmarsh and mudflat development is autocyclic rather than allocyclic. Generally, transgressive and regressive events are related to disposition of coastal barriers and these are superimposed on a general facies evolution governed by regional sea-level change. Predictions about how this barrier coastline might respond to increased rates of regional sea-level change caused by global warming, or climatic events like increased storminess, require an understanding of how specific segments of the coastline have responded over millennial time-scales. This longer-term evolution provides the baseline information for decision making and management strategy. It is likely that sandy sediment supply is limited on the NNC and this implies that the barriers will continue to move landward, probably at increased rates relative to today, suggesting that parts of the NNC will become more vulnerable to erosion and flooding.