Tectonic implications of new Appalachian Ultradeep Core Hole (ADCOH) seismic reflection data from the crystalline southern Appalachians

Summary. Some 180 km of new VIBROSEIS profiles have been acquired in the southern Appalachian Inner Piedmont, Brevard fault zone and eastern Blue Ridge as part of the ADCOH Project site investigation. These data are of the highest quality yet obtained in a crystalline terrane in the US, perhaps in the world, and reveal several conclusions that should have a direct bearing upon the world-wide nature of composite crystalline thrust sheets and their modes of interaction with the platform rocks beneath. Strong reflections previously interpreted as the base of the crystalline sheet are clearly part of the platform sedimentary (clastic rocks) sequence resting upon the autochthonous basement and early Palaeozoic rift basins. This reflection package and related transparent zones are clearly repeated beneath the crystalline sheet indicating a complex of thrusts repeating units within the platform succession. Reflectors (granitoid-amplibolite contacts) in the crystalline sheet in the Inner Piedmont represent recumbent folds of similar wavelengths and amplitudes to folds mappable on the surface. Duplexing of platform rocks beneath the crystalline sheet appears to have resulted in doming of the crystalline sheet. Similarly, duplex formation in the platform was probably controlled by both the thickness of the crystalline sheet and the rheological properties of the platform succession.     

BASS measurements of currents, waves, stress, and turbulence in theNorth Sea bottom-boundary layer

Shallow-water-boundary layers are affected by current, waves, bottom topography, and stratification. Precise turbulence measurements through such regions are difficult. A deployment of a BASS (Benthic Acoustic Stress Sensor) tripod in November 1997 in the North Sea in 15 m of water provides a data set to examine turbulent boundary layer models. The deployment spanned both calm and storm sea conditions, had strong tidal currents, the location was uniform horizontally, and the bottom-boundary layer was well mixed in temperature. Estimates of stress derived from the covariance, log-fit, drag-law, and inertial-dissipation method have been compared. The covariance stress estimate had the largest sample to sample scatter, but from theoretical considerations should give the best estimate in stratified flow. The drag-law estimate gave the least sampling variability but suffers from the user having to measure a drag coefficient by some other method. The inertial-dissipation method was more tolerant to sensor misalignment, had the second greatest sampling variability, and could not be used to measure stress during slack tide. Averaging many semidiurnal tidal cycles showed greater tidal asymmetry of the log-fit stress than the covariance or inertial-dissipation stress estimates. Turbulent energy generation and dissipation were measured and balanced individually for the upper two sensors and followed a one-over-height-above-bottom profile     

Environmental regulation of the burrow depth distribution of the sand-beach amphipod Talitrus saltator

The diurnal burrow depth distribution of Talitrus saltator, a sand-beach talitrid amphipod was examined in relation to moisture content and temperature profiles of the substrate. Individuals burrow to depths maintaining a moisture content of between 2·0 and 4·0% irrespective of the temperature profile, and therefore burrow depth is suggested to be regulated primarily by the requirements of the amphipods for an optimal humidity environment.     

The C+, C,CO network in interstellar clouds

A chemical network determining the formation and destruction of C⁺, C, and CO and other species is set up and applied to spherical clouds in the normal interstellar radiation field. The spherical geometry adopted gives results which are different from those for slab models. The sensitivity of chemical species to chemical and astronomical parameters is explored. The relevance of this work to the observations is discussed.     

Construction and use of an inexpensive, lightweight free-fall penetrometer: applications to paleolimnological research

This paper describes the construction of an inexpensive, lightweight, free-fall lake sediment penetrometer with application to paleolimnological research. This penetrometer is suitable for use in a variety of fresh water lake settings. Data are collected on a laptop PC, Palm OS handheld, or a Texas Instruments handheld data collection unit and are analysed using commercially available software. The quality of these data are adequate for determining changes in substrate type based on hardness. The unit can also be used to locate sites for optimum penetration of gravity cores and to calibrate sonar records. Addition of up to three optional transducers could expand the capabilities of the unit. Other potential uses include the determination of specific geotechnical properties of the lake sediment including the undrained shear strength.     

GIS in Participatory Research: Assessing the Impact of Landmines on Communities in North-west Cambodia

The view of GIS, adopted by many, as an undemocratic and divisive technology is perhaps most poignant in settings where financial and skills‐based resources are limited, notably in lower‐income countries. Where those countries are also recovering from a period of military conflict there would at first sight seem to be little opportunity for employing GIS as part of a socially‐sensitive approach to ‘development’. This paper explores the potential for using GIS in participatory approaches to gathering and analysing geographical information on human‐environment interactions in post‐conflict settings. We discuss empirical work from northwest Cambodia where GIS and participatory methods have been integrated to assess risk to local communities from landmines and to develop priorities for landmine clearance. In juxtaposing ‘official’, spatially‐referenced data with indigenous geographical knowledge in this study we seek to privilege meaningful geographical understandings over conventional notions of spatial ‘accuracy’. In so doing we carry out a Participatory Mine Impact Assessment (PMIA) to explore spatial activities among local populations in mine‐contaminated communities and to help identify improved strategies for returning refugees in re‐establishing livelihoods.     

Incorporation of organic tritium (3H) by marine organisms and sediment in the severn estuary/Bristol channel (UK).

Discharges of tritium (3H) into the Severn estuary/Bristol Channel (UK) arise from the authorized release of wastes from nuclear power plants at Hinkley Point and Berkley/Oldbury and from the Nycomed-Amersham radiochemical plant, via the sewer system, at Cardiff. The wastes from the nuclear power plants probably consist almost entirely of 3H2O, whereas those from the radiochemical plant also include uncharacterized 3H labelled organic compounds. The total 3H concentrations in demersal fish and other benthic organisms in the vicinity of the Cardiff Eastern sewer outfall are significantly elevated compared to those observed around other UK nuclear establishments. Concentrations in filtered seawater were approximately 10 Bq kg(-1) whilst levels in surface sediment, seaweed (Fucus vesiculosis) and mussels (Mytilus edulis)/flounder (Platichthys flesus) were in the order of 6 x 10(2), 2 x 10(3), and 10(5) Bq kg(-1) (dry weight), respectively. Almost all the 3H found in sediment and biota were organically bound tritium (OBT). The high concentration in these materials, relative to that in seawater, is due to the presence of bioavailable organic 3H labelled compounds in the radiochemical waste. It is suggested that bioaccumulation of 3H by benthic organisms and demersal fish occurs primarily via a pathway of physico-chemical sorption/bacterial transformation of dissolved 3H labelled organic compounds into particulate organic matter, and subsequent transfer up a web of sediment dwelling microbes and meiofauna. Variations in 3H accumulation between individual organisms have been interpreted in terms of their different feeding behaviour. Relatively low concentrations were observed in the herbivorous winkle (Littorina littorea) and the pelagic Sprat (Spratus spratus) compared with other benthic organisms and demersal fish. The elevated 3H concentrations in seafood, due to bioaccumulation of OBT, have low radiological significance even for the local critical group of seafood consumers.     

Integrated coastal dune management: checklists

The main objective was to assess dune vulnerability—a reduced ability to adapt to change, which is of serious concern not only in Western Europe but on a world scale. A main root checklist together with two daughter ones were devised in order to achieve this objective. The main root checklist comprised six categories (site and dune morphology, beach condition, surface character of the seaward 200 m of dune, vegetation, anthropogenic impact and protection measures in place) and dunes were classified according to their vulnerability compared to protection measures. The Resilience daughter checklist encompassed dune erosion, sand input, sand retention, degradation by use and dune management. This was compared with risk factors such as obstacles to dune transgression and recreation. The geomorphology, aeolian, vegetation, anthropogenic, marine influences daughter checklist looked at 30 dune systems in the Gulf of Cadiz and assessed dune condition by a dune vulnerability index based on the above conditioning influences. Values for all checklists were expressed as percentages. Over 200 dune sites in Spain, France, Portugal and the UK were analysed by means of these checklists. Results confirmed that regional trends concerned with dune vulnerability could be assessed, although successful differentiation at the end of the dune spectrum (large sand sheets, e.g. Pyla, France and meadow formation, e.g. many of the UK systems) and at the local scale were muted. An innovative aerial digital photographic system was developed and photographs were successfully used to assess dune condition, anthropogenic impact on dune systems, etc., i.e. the checklist parameters and was used to modify checklist procedures in assessing regional dune degradation. Ca 70% of the checklist parameters could be obtained by this means. This also provided a photographic record of the current dune condition. Principal component analysis provided a strong justification for the majority of checklist questions and the approach and relevance of the technique. The enumerated techniques provide valuable tools for dune managers. Rapid assessment of large areas of coastline can be obtained at a low cost and the resulting remote sensed images can provide a permanent record of the condition of the photographed dunes.     

An evaluation of financial globalization under fund-manager capitalism: the case of the UK unit trust industry

Drawing upon evidence from the UK unit trust industry, this paper evaluates the extent and nature of financial globalization. It finds that despite this rapidly growing and prominent form of fund-manager capitalism operating with increasingly mobile capital in a more inter-connected deregulated world, this does not signal the advent of homeless capital and the end of geography.