bluuebunny/crossref_metadata_2025 huggingface dataset:
Cell Sheet Engineering — The Adolescence of Tissue Engineering
Authors: Yang Joseph , Yamato Masayuki , Okano Teruo
Published: September 2007

The article is on cell sheet engineering. It summarizes tissue engineering from its beginnings to the recent latest developments.
In Vivo Bioimaging Using Transgenic Rats and The Role Of Bone Marrow Cells In Wound Healing
Authors: Murakami Takashi , Inoue Hirokazu , Kobayashi Eiji
Published: September 2007

The article discusses the importance of rats in regenerative medicine research. It touches on wound healing using bone marrow derived cells and the artifical dermis.
AN OVERVIEW OF IMCB IN THE 21ST CENTURY
Authors: Lane David P.
Published: September 2007

The article is an overview of IMCB in the 21st century. It mentions the work done by the institution and the focus of the institution, which are: Cancer Biology, Cell Biology, Developmental biology, infectious diseases, structural biology and translational research.
Bioinformatics Institute — Opening New Frontiers in Biology
Authors: Rajagopal Guna , Mishra Santosh
Published: September 2007

This article is about the research done in Bioinformatics Institute. It describes the research focus of the team at BII. It also summarizes the ongoing collaborations and partnerships the institution has with other partners.
Bioprocessing Technology Institute
Authors: Oh Steve
Published: September 2007

The article describes the strategic areas of research BTI is doing. It touches on the Hight Output (HOT) cell lines and also the novel antibodies to human embryonic stem cells. It also discusses the collaboration with Microbia on secondary metabolite production.
The Genome Institute of Singapore
Authors: Liu Edison T.
Published: September 2007

The article is a summary of the research done in GIS. It touches on the focus on systems and integrative biology and GIS's efforts in collaborating with international organizations.
Hydrocarbon potential of the Kish Bank Basin: integration within a regional model for the Greater Irish Sea Basin
Authors: Dunford G. M. , Dancer P. N. , Long K. D.
Published: September 2007

The Kish Bank Basin lies in the western Irish Sea
c.
20 km east of Dublin. It is one of a number of remnants of a larger Permo-Triassic basin system that may have extended across the whole of the Irish Sea. It has a geological history similar to that of the East Irish Sea Basin, initially developing by the reactivation of Caledonian faults that controlled subsequent deposition during Dinantian and Namurian time, with Westphalian deposition in a sag-basin that overstepped the adjacent basement highs. Variscan dextral transpression resulted in the formation of the Codling and Bray faults, and Permian to Jurassic extension formed a set of north-south-trending faults. Liassic outliers are preserved in the hanging walls of the basin margin faults. Early Cretaceous uplift was followed by chalk deposition. Tertiary movements reactivated older faults, isolating the Kish Bank Basin, and producing 9 km of dextral strike-slip along the Codling Fault Zone. The main reservoir in the hydrocarbon play is provided by the Sherwood Sandstone Group, as successfully exploited in the East Irish Sea. Three wells have been drilled to test this reservoir. These encountered high-quality Sherwood Sandstone reservoirs beneath the good potential seal of the Mercia Mudstone Group (which included thick halites). Source rock potential is from either the Westphalian Coal Measures, as penetrated in well 33/22-1, or from inferred Dinantian to Namurian basinal shales. There is good evidence of an active source system, with oil shows in wells 33/17-1 and 33/22-1, data from geochemical analysis of sea-bed cores, a ‘Seepfinder’ survey, sea-bed mounds and seismic evidence of shallow gas. The main risks of the play are the migration pathway and the timing of trap formation with respect to migration. Migration favours the eastern side of the basin, and many of the tilted fault blocks that formed during Permian to Jurassic time have been modified by Early Cretaceous inversion and by Tertiary strike-slip compression. All of the structures that have been drilled to date have been either formed or modified after the time of peak hydrocarbon generation and migration.
The geology and geophysics of the SW Kinsale gas accumulation
Authors: O'Sullivan John M.
Published: September 2007

The SW Kinsale gas accumulation is located in blocks 48/20 and 48/25 in the North Celtic Sea Basin, 50 km off the south coast of Ireland. The field lies in
c.
100 m of water. The discovery well, 48/25-2, was drilled in 1971 and encountered gas-bearing fluviatile sandstones in the Lower Cretaceous Wealden sequence. In 1995, well 48/25-3 was drilled close to the discovery well on the southwestern limb of the Kinsale Head anticline, which is thought to have formed during Tertiary basin inversion. The well data indicate that this southwestern area is in pressure isolation from the main Kinsale Head Field, which lies in the central and eastern sectors of the structure. In 1997 a 3D seismic survey was acquired to assess the suitability of the field as a potential gas storage site. These data suggest that SW Kinsale is in structural isolation from the main Kinsale Head Field. Mapping of the 3D volume reveals SW Kinsale to comprise a relatively simple low-relief anticline. There is
c.
160 m of closure from −810 m true vertical depth sub-sea (TVDSS) at its crest to −968 m TVDSS along a syncline to the north. The accumulation is thought to have a shared gaswater contact with the main Kinsale Head Field at −945 m TVDSS, beneath which lies a transition zone to −968 m TVDSS. The area within closure is close to 1200 ha. These data also suggest that the reservoir has undergone a minimal degree of structural compartmentalization. A major Wealden channel axis is interpreted to transect the field. Southwest Kinsale is thought to contain 1.1–1.4 BCM (billion cubic metres) gas initially in place with about 0.85 BCM recoverable. The field was recently developed as a single well sub-sea tieback to the Kinsale Bravo platform. First gas deliveries from the field took place in late 1999.
Exploring in the Slyne Basin: a geophysical challenge
Authors: Dancer P. Nick , Pillar Nick W.
Published: September 2007

The Slyne Basin lies
c.
60 km offshore west of Ireland, in water depths of 200–500 m. It consists of three asymmetric half-graben that are separated by complex structural transfer zones. Sporadic exploration in the basin over the last 20 years has resulted in the drilling of four exploration wells, which have yielded one gas discovery. Well 18/20-1 (Corrib) successfully tested a faulted anticlinal structure and encountered gas in the Triassic Sherwood Sandstone Formation. Although a number of other potential hydrocarbon traps have been identified in the Slyne Basin, the poor quality of the seismic data, plus the presence of complex transfer zones, has generated considerable uncertainty with respect to the correlation of seismic markers. A primary control on the seismic data quality is the presence of near-sea-bed, high-velocity, Tertiary volcanic and Cretaceous chalk layers. These result in very strong and long multiple trains, energy scattering, mode conversion and attenuation. Studies suggest that improved signal penetration can be achieved when the seismic acquisition is focused on the low-frequency end of the spectrum. However, predictive multiple attenuation has proved ineffective because of the complex nature of the multiple generators. An approach based on detailed velocity analysis and the judicious parameterization of more than one pass of Radon demultiple has yielded good results. This approach, coupled with 3D acquisition and processing with its inherent increase in signal-to-noise ratio, has led to a dramatic improvement in the seismic data quality in the Corrib area.
Provenance implications of reworked palynomorphs in Mesozoic successions of the Porcupine and North Porcupine basins, offshore Ireland
Authors: Smith J. , Higgs K. T.
Published: September 2007

Reworked Late Carboniferous palynomorphs are recorded from mudrocks within Upper Jurassic and Lower Cretaceous sandstone-prone horizons from five wells (26/28-A1, 26/28-A1Z, 35/19-1, 35/8-1 and 35/8-2) in the Porcupine and North Porcupine Basin area, offshore western Ireland. Reworked palynomorphs are recognized by their anomalous biostratigraphic age; differences in colour and preservation are less significant. The reworked palynomorphs are remarkably well preserved and are thermally relatively immature in comparison with
in situ
onshore palynomorphs of a similar age. This indicates that the source of the reworked palynomorphs was not the onshore Upper Carboniferous successions of the Irish mainland. They were probably derived, along with the associated sand, from the immediate basin margin to the east, as this is the only area where there is suitably aged material with an appropriate thermal history. Reworking of rift flank Late Carboniferous material was thus an important factor in the provenance of Mesozoic sandstone horizons throughout the Porcupine and North Porcupine basins and surrounding areas. The study demonstrates that the investigation of reworked palynomorphs can be an important aspect of provenance studies in general.
Cenozoic and Cretaceous transient uplift in the Porcupine Basin and its relationship to a mantle plume
Authors: Jones Stephen M. , White Nicky , Lovell Bryan
Published: September 2007

The Mesozoic and Cenozoic history of the Porcupine Basin may be broadly summarized as a Jurassic synrift phase, followed by Cretaceous and Cenozoic post-rift subsidence. Two periods, Early Cretaceous and Early Eocene times, do not fit the simple pattern of post-rift subsidence and are characterized by increased sedimentation. We recognize distinctive sedimentological responses to the basin flanks being either exposed or submerged, and infer that transient regional uplift caused the Early Eocene event. Modelling subsidence histories of wells and of the Porcupine Bank allows quantification of the magnitude and timing of anomalous uplift and subsidence. Transient uplift of 300–600 m occurred at the Paleocene-Eocene boundary, followed by subsidence of 500–800 m after Early Eocene time, over a period with a minimum length of 25 Ma and a maximum of 55 Ma. Renewed rifting is unlikely to be responsible for the Paleogene subsidence because it cannot account for the preceding uplift, and significant normal faults of Paleogene age are absent. A Paleogene uplift-subsidence cycle has also been noted in the basins surrounding Scotland and along Hatton continental margin. One way to explain regional subsidence between Eocene time and the present is that the European plate moved off the topographic swell above the Iceland plume following continental separation between Greenland and Europe in Early Eocene time. Another possibility is that an anomalously hot layerc.50 km thick was emplaced beneath the entire region just before the onset of sea-floor spreading in Early Eocene time and was then dissipated by convection following continental separation. A Cretaceous transient uplift-subsidence cycle that shares many similarities with the Paleogene cycle is also recognized. Immediately following Late Jurassic rifting, 200–700 m transient uplift occurred in Early Cretaceous time, followed by 0–500 m subsidence coeval with the onset of sea-floor spreading at the Goban Spur margin. The Cretaceous uplift-subsidence cycle might also be caused by anomalously hot mantle.
Carbonate mounds and slope failures in the Porcupine Basin: a development model involving fluid venting
Authors: Henriet J. P. , De Mol B. , Vanneste M. , Huvenne V. , Van Rooij D.
Published: September 2007

High-resolution reflection seismic investigations carried out in the Porcupine Basin, SW of Ireland, have shed light on the presence of several provinces of giant carbonate mounds. An intriguing setting is found on the northern slope of the basin. A cluster of surface mounds appears to be flanked by a large upslope, crescent-shaped province of buried mounds. Below the transitional zone, large imbricated slide scars suggest repeated failures. The buried mounds rise from an undisturbed basal horizon and seem to represent a single event, confined in time and space. Both high-resolution and industrial seismic data reveal a close vertical match of the mound cluster with a lower, buried sea-bed failure, where hydrate build-up may have played a role. The latter association may not be entirely fortuitous. It is suggested that gas venting may have triggered the formation of the mound clusters, and that the underlying sea-bed failure forms a previous but different expression of gas venting, on a common, episodic fluid migration pathway but under strongly contrasting bottom water temperature conditions.
Interpretation of transverse gravity lineaments in the Rockall Basin
Authors: McGrane K. , Readman P. W. , O’Reilly B. M.
Published: September 2007

A number of regional transverse gravity lineaments crosscutting the Rockall Basin are interpreted from satellite gravity data. Euler deconvolution carried out on gravity data along a wide-angle seismic profile indicates that a major NW-SE-trending lineament within the basin reflects pronounced variations in crustal structure and sedimentary thickness. These thickness variations are interpreted as the result of cross-basin faulting along a zone defined by this lineament. Transverse gravity lineaments to the north of this feature are similarly interpreted as major cross-basin fault zones.
The structural style and evolution of the Bróna Basin
Authors: Thomson A. , McWilliam A.
Published: September 2007

The Bróna Basin lies on the eastern margin of the Rockall Basin and has a NNE-SSW trend. Although at present undrilled it is believed to contain Carboniferous, Triassic and Jurassic to Lower Cretaceous strata. It probably formed as a product of Late Jurassic rifting, which ultimately resulted in the creation of the Rockall Basin. The basin history is complex and its present form is the result of pre-Jurassic structuring, Late Jurassic rifting, later (latest Jurassic to earliest Cretaceous, and Early Tertiary) compressional pulses, and the effects of thermal subsidence in the adjacent Rockall Basin. The development of the Bróna Basin is of direct relevance to understanding the geological evolution of the other marginal basins lying on the flanks of the Rockall Basin, and to the Rockall region as a whole.
A Mid- to Late Cenozoic tectonostratigraphic framework for the Rockall Trough
Authors: Stoker M. S. , Van Weering T. C. E. , Svaerdborg T.
Published: September 2007

Regional subsidence in late Eocene time resulted in a marked change in the style of sedimentation in the Rockall Trough, coincident with the onset of bottom-current activity in the region. This subsidence is manifest by a shut-down of shelf-derived sediment supply, and the formation of a deep-water unconformity (reflector C30) caused by bottom-current erosion. The unconformity is particularly enhanced on the flanks of the basin where the downwarped and eroded surface of Eocene and older strata is onlapped by middle to upper Cenozoic sediments. The latter comprise three megasequences, RTc (of late Eocene to early Miocene age), RTb (of early Miocene to early Pliocene age) and RTa (of early Pliocene to Holocene age), which consist predominantly of deep-marine contourites, although a prograding clastic wedge has built out along the Hebrides-Malin margin since early Pliocene time. These megasequences reflect a gross three-stage depositional history; predominantly a response to intra-plate tectonism that modified sedimentation patterns and palaeoceanographic circulation. Megasequences RTc and RTb are separated by reflector C20, a reflective zone formed by lithification and diagenetic changes in lower Miocene strata, whereas RTb and RTa are separated by reflector C10, an early Pliocene angular unconformity. The development of C20 and C10 reflects major phases of Neogene basin evolution and can be linked, respectively, to the submergence of the Greenland-Scotland Ridge and the uplift and erosion of northern Britain and Ireland.
Is the water still hot? Sustainability and the thermal springs at Bath, England
Authors: Atkinson T. C. , Davison R. M.
Published: September 2007

The hot springs at Bath are the largest natural thermal source in Britain. Sustainable use of the waters for a spa requires maintenance of their temperature and flow rate. Together with smaller springs at Hotwells, Bristol, they form the outflow from a regional thermal aquifer that occurs where the Carboniferous Limestone is buried at depths > 2.7 km in the Bristol-Bath structural basin. The aquifer is recharged via limestone outcrops forming the south and west portions of the basin rim. Current knowledge of the basin’s structure is reviewed, and important uncertainties identified concerning the hydrogeological role of thrust faults which may cut the limestone at depth. A simple numerical model is used to determine the possible influence of thrusts upon groundwater flow within the thermal aquifer. Comparison of the modelled flow patterns with geochemical data and structure contours eliminates the hypothesis that thrusts completely disrupt the continuity of the aquifer. The most successful model is used to simulate the possible impact of dewatering by large quarries at the limestone outcrops north and south of Bath. Substantial reductions in modelled flow at Bath result from proposed dewatering in the eastern Mendips, although the steady-state approach adopted has severe limitations in that it does not take account of the incremental staging of actual dewatering, nor allow for partial restitution of groundwater levels. The geological uncertainties highlighted by the modelling could be addressed by future research into the effect of thrusts on the continuity of the Carboniferous Limestone. More refined modelling to predict the timing of possible impacts of quarry dewatering will require measurements of the storativity of the thermal aquifer.
Institutional development for sustainable groundwater management — an Arabian perspective
Authors: Young M.E.
Published: September 2007

In the Arabian Peninsula, hydrogeological and engineering solutions have failed to solve the severe and worsening problem of unsustainable groundwater abstraction, which threatens rural environments and livelihoods. Conventional western fiscal and regulatory measures to reduce abstractions seem to be impracticable in the present institutional and social contexts. In the region, groundwater rights without volume limitations are distributed mostly among numerous private well owners, and individual interests predominate over a communal imperative for aquifer sustainability. The solution may lie more in modifying the institutional context than in attempting to introduce official controls. This would involve the decentralization of water resources management to a basin or aquifer level and the development of local users associations. Water users associations could improve users’ understanding of local hydrological limitations, promote conservation among irrigators, and cooperatively develop sustainable strategies and rules, which might ultimately include tradable rights and quotas. Government subsidies and incentives are necessary. Essential components of this participatory approach are strong leadership at national and local levels, the active engagement and leadership of Islamic institutions, and the use of modern communication methods.
Incorporation of groundwater modelling in the sustainable management of groundwater resources
Authors: Hulme P. , Fletcher S. , Brown L.
Published: September 2007

Numerical groundwater models have been used by the Environment Agency and its predecessors for over 30 years to help understand the behaviour of aquifer systems and as one of the tools to help manage groundwater resources effectively. The Agency has recently reviewed the past use of distributed numerical models with a view to improving their utilization for groundwater resource management. This is particularly important due to the changes in groundwater management strategies that will occur as a consequence of the new European Union Water Framework Directive. The review has highlighted a number of areas where changes are desirable. Three in particular are the role and importance of the conceptual model, the requirement for a nationally coordinated programme of modelling and the need to develop further the Agency’s in-house modelling expertise. The Agency is currently developing proposals in these and other areas as part of a Research and Development project.
Groundwater sustainability and water resources planning for the East Midlands Resource Zone
Authors: Hudson M.
Published: September 2007

The East Midlands Resource Zone is one of three water resource zones identified by Severn Trent Water in its recent Water Resources Plan, submitted to the Environment Agency. The public water supply to this resource zone is derived from a complex mix of surface and ground water sources, and supplies nearly 3 million people. The most significant aquifer in the East Midlands is the Nottinghamshire Sherwood Sandstone which supplies approximately one quarter of the deployable output for the resource zone (some 200 Ml d
−1
). This aquifer is over-licensed and historically abstraction has exceeded the long-term average recharge. Severn Trent Water has agreed reductions in groundwater licences from this aquifer; however more reductions are targeted by the Environment Agency following its recent reassessment of resources and the introduction of the ‘environmental fraction’. In order to meet the existing resource shortfall and the continuing pressure to reduce abstraction licences, Severn Trent Water propose to support its new surface water abstraction on the River Trent by developing groundwater resources beneath the City of Birmingham. Significant further work is required by water industry regulators and Severn Trent to resolve the projected long-term supply deficit.
The High Plains Aquifer, USA: groundwater development and sustainability
Authors: Dennehy K. F. , Litke D. W. , McMahon P. B.
Published: September 2007

The High Plains Aquifer, located in the United States, is one of the largest freshwater aquifers in the world and is threatened by continued decline in water levels and deteriorating water quality. Understanding the physical and cultural features of this area is essential to assessing the factors that affect this groundwater resource. About 270f the irrigated land in the United States overlies this aquifer, which yields about 300f the nation’s groundwater used for irrigation of crops including wheat, corn, sorghum, cotton and alfalfa. In addition, the aquifer provides drinking water to 820f the 2.3 million people who live within the aquifer boundary. The High Plains Aquifer has been significantly impacted by human activities. Groundwater withdrawals from the aquifer exceed recharge in many areas, resulting in substantial declines in groundwater level. Residents once believed that the aquifer was an unlimited resource of high-quality water, but they now face the prospect that much of the water may be gone in the near future. Also, agricultural chemicals are affecting the groundwater quality. Increasing concentrations of nitrate and salinity can first impair the use of the water for public supply and then affect its suitability for irrigation. A variety of technical and institutional measures are currently being planned and implemented across the aquifer area in an attempt to sustain this groundwater resource for future generations. However, because groundwater withdrawals remain high and water quality impairments are becoming more commonplace, the sustainability of the High Plains Aquifer is uncertain.
Sustainable groundwater resources in a hard-rock island aquifer — the Channel Island of Guernsey
Authors: Robins N. S. , Griffiths K. J. , Merrin P. D. , Darling W.G.
Published: September 2007

The annual volume of water in the Guernsey public supply, which derives largely from surface storage, is approximately 5 Mm
3
. Additional abstraction from private surface and groundwater sources amounts to a further 1.5 Mm
3
. A shallow weathered zone in ancient crystalline metamorphic rocks forms the main aquifer, and this has a significant resource potential in maintaining baseflow to streams. The average annual water budget for the island is 831 mm rainfall, which supports 613 mm potential evapotranspiration, 90 mm surface runoff and 128 mm groundwater recharge. These figures contrast with a poor rainfall year in which infiltration may be zero; the annual variation in rainfall from the long-term mean is often considerable. Annual rainfall has also been declining on the island since the 1940s, and although Guernsey has survived droughts in the past it may be less able to do so in the future. Groundwater on the island is moderately mineralized, but over half of the 21 samples collected recently contained nitrate at concentrations greater than the EU maximum admissible concentration 11.3 mg-N l
−1
. Some of the nitrate may derive from leaking cesspits, but past application of nitrogenous fertilizer to cultivated land accounts for the major component. Attempts at groundwater dating by analysis of chlorofluorocarbon species at a small number of sites was hindered by contamination, although much of the water sampled is apparently young, and recently recharged. The long-term sustainability of the shallow island aquifer and its associated surface waters requires careful husbanding to protect it from conflicting land use interests and water demands.
Groundwater quality in the Valigamam region of the Jaffna Peninsula, Sri Lanka
Authors: Rajasooriyar L. , Mathavan V. , Dharmagunawardhane H. A , Nandakumar V.
Published: September 2007

The Valigamam region is underlain by a Miocene limestone formation and a highly porous soil cover. The region is totally dependent on groundwater to meet its agricultural, industrial and domestic needs, since other sources of water are seasonal. Recharge from rainfall is limited by high run-off and evapotranspirational losses. The region experiences water supply problems due to high concentrations of chloride, total hardness and nitrate in groundwater. The spatial distribution of chloride varies from year to year, with maximum concentrations experienced during or after the wet season. The major factor explaining high chloride concentrations is the excessive extraction of groundwater that results in saline intrusion from the sea or lagoonal areas. In a large proportion of wells sampled for nitrate, levels exceed the WHO standard due to intensive agricultural practices involving very high inputs of artificial and natural fertilizers and the improper construction of latrine soakaway pits. To improve groundwater quality in the Jaffna Peninsula will require controls on the location of new wells, a revision of existing and future pumping rates and a change in agricultural practices. It is imperative that future work in the region should focus on combining groundwater management and sustainable agricultural practice.
Will reductions in groundwater abstractions improve low river flows?
Authors: Rushton K. R.
Published: September 2007

It is a commonly held view that a reduction in groundwater abstractions in many heavily exploited aquifers is likely to improve low flows in rivers. In most aquifers, but especially in chalk and limestone aquifers, the improvement in flows may only be small compared with the reduction in abstraction. Using conceptual and numerical models, the relevant flow processes in chalk and limestone aquifers are examined with special reference to the impact of pumped boreholes on stream and river flows under conditions of differing transmissivities resulting from high or low groundwater heads. The key response is that much of the winter recharge is lost to high winter river flows with only a small proportion of the recharge being stored in the aquifer and available in the summer. Consequently, the low summer river flows, which depend primarily on the areas local to the rivers, may not be strongly influenced by pumped boreholes unless these are close to the rivers. Case studies are used to illustrate the discussion.
A probabilistic management system to optimize the use of urban groundwater
Authors: Davison R. M. , Prabnarong P. , Whittaker J. J. , Lerner D. N.
Published: September 2007

Urban groundwater is an underused resource mostly due to the perceived risk of contamination; conversely rural groundwater is being over-exploited. To enable urban groundwater to be utilized effectively a probabilistic water management tool has been developed. The management tool combines three models to identify the best use for water pumped from a user-defined location. The probabilistic catchment zone model determines the spatial distribution of the probability that water originating from a given point in the aquifer reaches the pumping well. The land-use model then identifies the potential contaminant sources in this region from a large set of GIS-based coverages and databases. The contaminant source data are passed to a pollution risk model that calculates the probability distribution for the concentration of a contaminant at the pumped borehole. Initial model validation using contaminant concentrations from two sites shows the model fits the available field data. These case studies show there is risk from chlorinated solvents but little risk from the BTEX compounds.
A brief overview of eruptions from ice-covered and ice-capped volcanic systems in Iceland during the past 11 centuries: frequency, periodicity and implications
Authors: Larsen Gudrún
Published: September 2007

Eruptions from partly ice-covered and ice-capped volcanic systems constitute nearly 60% of all known historical (i.e. in the past 11 centuries) eruptions in Iceland. Since the fourteenth century such eruptions have been reported in contemporary or near-contemporary documents. At least 120 historical eruptions have broken through the ice on the glaciated parts of five volcanic systems and have left tephra layers in ice and soil, or been recorded at the time. An unknown number of eruptions did not breach the overlying ice and left no record at all. Beginning as subglacial eruptions, most eruptions break through the ice in minutes, hours or days and can last from a few days to several months. A single vent or the whole length of a fissure may then emerge to emit highly-fragmented tephra in hydromagmatic explosions of varying strength. The volume of airborne tephra varies by at least four orders of magnitude with dispersal range varying from near-vent to transatlantic. In most of the eruptions the magma was of basaltic composition. Eruption frequency is highest within the Grímsvötn system where up to seven eruptions every 40 years have occurred during peaks of activity and at least 70 eruptions over historical time. The observed pattern of temporally and spatially close eruptions, separated by periods of low or no activity, leaves open the question whether pre-Holocene deposits of several closely spaced subglacial eruptions can be securely distinguished from those formed in a single subglacial eruption.
Architecture and evolution of hydrovolcanic deltas in Marie Byrd Land, Antarctica
Authors: Le Masurier W. E.
Published: September 2007

The Marie Byrd Land volcanic province is a late Cenozoic alkaline basalt-trachyte volcanic field on the Pacific coast of West Antarctica. Most of these volcanoes are partially buried beneath the West Antarctic ice sheet, but in some, a combination of tectonic uplift and lowering of ice level has exposed basal hydrovolcanic sections produced by eruptions in an englacial environment. Some of the largest and best preserved hydrovolcanic structures are delta-like in form, with gentle distal slopes, and foreset bedded deposits composed of hyaloclastites, pillow breccias, pillow lavas, subaerial flows and air fall tephras. Three broad categories of processes related to delta evolution are described here; (1) flow of lava from a subaerial to an englacial environment; (2) intrusion of dykes and sills; and (3) edifice settling, which includes a variety of down-slope movement phenomena. This paper focuses on documenting post-depositional structures that are superbly exposed in these deltas. It describes the apparently province-wide lack of pillow lava cores in Marie Byrd Land englacial volcanoes, and factors that may be related to this anomaly, and it describes characteristics of hyaloclastites that are relevant to future glaciological, sedimentological and geophysical studies of the West Antarctic ice sheet.
Lithofacies analysis and
40
Ar/
39
Ar geochronology of ice-volcano interactions at Mt. Murphy and the Crary Mountains, Marie Byrd Land, Antarctica
Authors: Wilch Thomas I. , McIntosh William C.
Published: September 2007

Palaeoenvironmental reconstructions and
40
Ar/
39
Ar geochronology of volcanism at Mt. Murphy and the Crary Mountains in eastern Marie Byrd Land (MBL), West Antarctica, provide records of changing ice levels of the West Antarctic Ice Sheet (WAIS) since the late Miocene. Interpretations of eruptive and depositional environments are based on lithofacies studies and indicate whether the volcanoes erupted below, near or above the level of the ice sheet. Seventy-seven new
40
Ar/
39
Ar dates offer a precise chronological frame-work for the ice volcanic history.

Late Miocene (9–8 Ma) basal volcanic sequences at Mt. Murphy and the Crary Mountains (Mt. Rees and Mt. Steere) exhibit fluctuations between ‘wet’ ice-contact lithofacies and ‘dry’ subaerial lithofacies. The ‘wet’ lithofacies include pillow lava and hyaloclastite breccia; the ‘dry’ lithofacies include massive and deuterically oxidized lava and associated welded breccia deposits. The sequences at Mt. Murphy include several erosion surfaces and tillites, which are inferred to represent fluctuations in the WAIS. At Mt. Rees and Mt. Steere, the alternating lithofacies form the constructional slopes of the volcano and are inferred to represent interactions with local slope ice that occurred above the level of the regional ice sheet.

The Miocene to Pleistocene volcanic history of the area provides a proxy record of ice-level changes in West Antarctica, with the following three major conclusions. First, the oldest evidence for a large-scale WAIS is from Late Miocene (
c.
9 Ma) glaciovolcanic sequences at Mt. Murphy and several other sites in Marie Byrd Land. The combined Mt. Murphy and Crary Mountains records indicate that ice-level expansions of the WAIS were more extensive at coastal sites than at inland sites. Second, the present-day WAIS appears to be in a near maximum configuration that has existed at several times since 9 Ma but was rarely exceeded. Finally, a significant expansion of the WAIS above its present-day level occurred at 590 ± 15 ka, when ice levels were 550 m higher at the coastal volcano, Mt. Murphy.
Layered, massive and thin sediments on Mars: possible Late Noachian to Late Amazonian tephra?
Authors: Chapman Mary G.
Published: September 2007

Data from instruments on the currently orbiting Mars Global Surveyor (MGS) suggest that as an alternative interpretation to lacustrine deposits, widespread sediments on Mars may be tephra deposits of variable age, formed in part by volcano-ice interactions. The materials are often associated with outcrops of mapped geological units that have each been previously interpreted as volcanic ash deposits with identified, but unconfirmed possible volcanic vents. Spectral investigation indicates that although some outcrops are basaltic, many show moderate to high concentrations of andesite, a composition at which large explosive eruptions may be possible. In addition, many outcrops are in areas suspected to be water/ice rich. On Earth, magma and groundwater can react to create violent explosive eruptions. Observations from MGS support a pyroclastic mechanism of deposition and show some morphologies consistent with volcano-ice interactions, including subaqueous eruptions. Perhaps MGS data are finally producing more definitive evidence of the widespread tephra that were predicted to be likely in the reduced atmospheric pressure of Mars.
Geochemical and mineralogical analyses of palagonitic tuffs and altered rinds of pillow basalts in Iceland and applications to Mars
Authors: Bishop Janice L. , Schiffman P. , Southard R.
Published: September 2007

Samples of altered pillow basalts and hyalotuffs were collected from a volcanic tuya and hyaloclastite ridge in western Iceland. Altered basaltic material from regions such as Hlöðufell tuya and Thórólfsfell ridge may be similar to the altered basaltic surface fines on Mars. Geochemical and mineralogical analyses have been performed on the Icelandic samples in order to characterize the properties that distinguish palagonitization from other forms of low temperature alteration in this environment. Major elements were measured using an electron microprobe and mienralogy was determined through X-ray diffraction and visible-infrared reflectance spectroscopy. The primary focus in this study was on the <2 μm size fractions of the Hlöðufell altered pillow basalt and Thórólfsfell palagonitic tuff samples. Both volcanic alteration products contain at least some smectite and serpentine clay minerals, as well as poorly crystalline layer silicates. The palagonitic tuff contains more crystalline clay minerals, fewer nanophase iron oxides/oxyhydroxides, and has a higher A1/Fe ratio compared to the altered pillow basalt. Spectra of the <2 μm fractions of both Icelandic samples share similarities with the extended visible region spectra of the bright martian soils measured by Pathfinder and the infrared spectra of the martian dust measured by spectrometers on the Mariner missions.
Freeze-thaw cycles and their influence on marble deterioration: a long-term experiment
Authors: Ondrasina Josef , Kirchner Dirk , Siegesmund Siegfried
Published: September 2007

The deterioration of three marbles (Palissandro, Sterzing and Carrara) differing in composition and rock fabric has been studied using measurements of the thermal dilatation in the temperature range from −40°C up to 60°C. A long-term freeze-thaw experiment was performed to characterize the frost weathering via Young’s modulus. The results show that the combined effect of heating and cooling under dry and water-saturated conditions significantly influences the material properties. The thermal dilatation and its anisotropy can be explained by the crystallographic preferred orientation of calcite and dolomite as well as with the thermal expansion behaviour of these minerals. The residual strain, i.e. the permanent length change, after thermal treatment is different for the investigated samples and less pronounced for the dolomitic marble from Palissandro. The hygric expansion is of only minor importance and weak in the phlogopite-bearing Palissandro sample within the direction parallel to the foliation.

Fresh and artificially weathered marbles were exposed to 204 freeze-thaw cycles. The Young’s modulus for the Carrara marble decreases from 55 GPa to 28 GPa while the porosity increases from 0.25% to 0.62%. The effect on the Palissandro and the calcitic Sterzing marbles is less pronounced while the artificially weathered ones clearly exhibit a drastic reduction in Young’s modulus.

The progressive loss in strength is caused by progressive microfracturing or the loss of cohesion along grain boundaries due to the crystallization pressure of ice growth. The experimental data along with existing theoretical models lead to the conclusion that the physical weathering of marble is influenced by cooling and heating under mid-European climatic conditions.
Evolution of the petrophysical properties of two types of Alsatian sandstone subjected to simulated freeze-thaw conditions
Authors: Thomachot C. , Jeannette D.
Published: September 2007

Stone monuments in Alsace (eastern France) are built with two types of Buntsandstein sandstone (Lower Triassic). Their different pore structures cause them to have mixed petrophysical properties and occasion a different response to frost. To understand these differences, frost simulation experiments have been carried out on samples of both stones. Four series of 30 freeze-thaw cycles were reproduced on samples maintained at constant saturation, either total or partial, without drying or rewetting. Macroscopic and microscopic change due to frost was observed by scanning electronic microscope, by mercury porosimetry and P-wave velocity measurements. Change of tensile strength and capillary kinetics was also assessed before and after each series. Results demonstrate that frost action increases heterogeneity of the porous network particularly in the initially more heterogeneous sandstone. When saturation is partial, no macroscopic cracking occurs and capillary absorption decreases. When saturation is total, macroscopic cracking prevails over microscopic heterogeneity and capillary absorption increases. Control tests have also been carried out to evaluate the effects induced by absorption-drying cycles without frost, and dilation experiments have been added to assess freeze-thaw action on dilation of sandstones. The results of all these experiments demonstrate that frost plays a less decisive part in the weathering mechanisms of stones than wetting-drying.
Salt weathering: a selective review
Authors: Doehne Eric
Published: September 2007

The past decade has seen a growing scientific interest in the still poorly understood subject of salt weathering, a phenomenon with significant cultural and economic consequences. This interest has led to an increase in research results and growing clarification of the roles salts play in weathering and decay. The development of improved mitigation methods to reduce the decay of building materials by salts has been a slow process, often arising from the analysis of unique field situations and otherwise dependent on simplified laboratory experiments and computer modelling. Collecting, reviewing, synthesizing and disseminating the existing data on salt weathering is a difficult task. The size and scope of the topic are mirrored in the diverse disciplines that have historically contributed to understanding the action of salts in porous materials and mitigation methods. Nevertheless, an appreciation of existing, even contradictory, data is an important tool for increasing understanding. There are now over 1800 research articles on the topic of salt weathering originating from several disciplines, as well as over 6000 references on the general problems of building material decay. In order to navigate such a vast collection of data and knowledge, this article describes the multidisciplinary nature of the study of salt damage to porous building materials, provides a framework for considering the complexity of salt damage, and serves as a selective literature survey largely focused on recent work and those articles with relevance for conservation.
Thermal tresses and microcracking in calcite and dolomite marbles via finite element modelling
Authors: Weiss Thomas , Siegesmund Siegfried , Fuller Edwin R.
Published: September 2007

Microstructure-based finite element simulations were used to study the thermomechanical behaviour of calcite and dolomite marbles. For a given mineral microstructure, thermal stresses and elastic strain energy varied with the single-crystal elastic constants and coefficients of thermal expansion. Moreover, they were a strong function of crystallographic texture. Given the same morphological microstructure and crystallographic texture, calcite had larger thermal stresses and elastic strain energy than dolomite. Hence, calcite has an earlier onset of microcracking upon either heating or cooling, and has a greater extent of microcracking at a given temperature differential. However, the variation in thermal stresses and microcracking propensity for either mineral with different randomly assigned textures was greater than the variations between the two minerals. The measured bulk thermal expansion anisotropy suggested that the random representations had some degree of texture. Simulations using the actual texture of the real microstructure, as determined by electron-backscattered diffraction, showed the largest degree of bulk thermal expansion anisotropy, the smallest strain energy, and hence the smallest amount of thermal microcracking. Microstructure-based finite element simulations are considered an excellent tool for elucidating myriad influences of microstructure and physical properties on the thermal degradation of marbles and other rocks.
Depositional environment and diagenesis as controlling factors for petro-physical properties and weathering resistance of siliciclastic dimension stones: integrative case study on the ‘Wesersandstein’ (northern Germany, Middle Buntsandstein)
Authors: Weber Jutta , Lepper Jochen
Published: September 2007

A case study on the ‘Wesersandstein’ (Middle Buntsandstein) indicates that weathering resistance and quality of dimension stones are functions of depositional environment, and of diagenetic alterations (eogenetic as well as mesogenetic) during geological history.

Two types of dimension stones, one deposited in a braided and the other in a meandering river system, were compared with respect to the fluvial architecture, the diagenetic modifications, the raw block prospectivity, and the petro-physical properties. The integrative synthesis of all these approaches indicates that depositional environment (type of fluvial architecture) and diagenesis (quartz cement and clay matrix contents) are the key processes which generally control the petro-physical properties and the weathering resistance of siliciclastic dimension stones. The highly quartz cemented ‘Grauer Wesersandstein’ with low clay matrix content, deposited as channel fill (braided river system), is characterized in general as a high quality dimension stone with very good petro-physical properties (e.g. high compressive strength, tensional strength, abrasion resistance, and freeze-thaw resistance) and high weathering resistance. In contrast to this, the ‘Roter Wesersandstein’, deposited as point bar and floodplain deposits of meandering rivers with low quartz cement and high clay matrix contents shows minor quality petro-physical properties (e.g. minor compressive strength, tensional strength, abrasion resistance, and freeze-thaw resistance) and weathering resistance.

This new integrative approach combines hitherto isolated studies on dimension stone quality. It shows the complex interrelations between the geological background on the one hand and specific dimension stone properties on the other hand.
The anisotropy of itacolumite flexibility
Authors: Siegesmund Siegfried , Vollbrecht Axel , Hulka Carola
Published: September 2007

Itacolumites are very special rocks due to their high flexibility. The investigated Brazilian itacolumites and associated non-flexible quartzites are of comparable composition but differ in their rock fabrics. The shape and size of quartz is mainly controlled by the mica fabric. Quartz textures and grain boundary migration features are indications for deformation at temperatures of about 500°C. The flexibility is mainly related to a penetrative network of open grain boundaries which enable a limited body rotation of individual quartz grains. Continuous layers of white mica display deformation features indicative of shear along the layer-parallel cleavage planes. As demonstrated by simple bending experiments, the flexibility is a highly anisotropic phenomenon which can be related to a directional dependence of grain shape fabrics and corresponding grain boundary pore spacing. According to quantitative estimates, the amount and anisotropy of bending can be explained by the rotation of separated quartz grains between layers of mica which act as flexural slip planes and are also responsible for the observed elastic rebound. Solution along grain boundaries, volumetric strain by thermal contraction of quartz and bulk extension are processes discussed for the origin of the extreme values of secondary grain boundary porosity.