Separation of multi-component NRM: A general method

A method is presented which can successfully isolate components of remanent magnetization having intermediate relative stability in a single rock sample which contains any number of remanence components with overlapping coercivity or blocking temperature spectra. The approach consists of analysis of the path swept out by the vector destroyed during a detailed alternating field or thermal demagnetization run. The point of intersection determined for any two neighboring great circle segments identified in such a difference vector path defines the direction of such a component. Samples cored from a fragment of a Jurassic pillow basalt, shown to contain several components of magnetization, serve to illustrate the utility of the method for the case when the Zijderveld approach is unsuccessful.     

Devonian basins of western norway - sedimentary response to tectonism and to varying tectonic context

The Devonian basins of western Norway are notable for their small size (<2000 km) and for the great stratigraphie thickness (up to 25 km) and the cyclic nature of their coarse-grained, alluvial infilling. These general features alone strongly suggest that tectonism was the dominant control on sedimentation but it is argued in particular that a coarsening-upwards motif, which permeates the three main basins usually on a scale of less than 200 m, was the direct sedimentary response to basin-floor subsidence. The coarsening-upwards is interpreted in terms of progradation of alluvial plain and alluvial fan facies in response to rapid lowering of the basin floor, while the overall cyclicity of the basin fills reflects repetition of such tectonic events. Detailed study within Hornelen Basin shows that the repeated coarsening-upwards theme overprints different sedimentary facies, and, in particular, the clastic wedges on opposite sides of the basin have contrasting thicknesses, radii, grain-size gradients and conglomerate types. These features suggest differing rates or degree of continuity of fault movement on opposite margins of the basin. Hornelen and Solund Basins, the two largest, are strongly contrasted in their differing mode of filling and sediment grade. It is suggested that this may reflect their development under strike-slip and dip-slip dominated regimes, respectively.     

Transport,fate, and infectivity of <Emphasis Type="Italic">Cryptosporidium parvum</Emphasis> oocysts released from manure and leached through macroporous soil

A major mode of transmission of Cryptosporidium parvum, a widespread waterborne pathogen, is via contaminated drinking and recreational waters. Oocyst transport to surface water can occur by deposition of manure directly in the water or by wash off in surface runoff. Oocyst transport to groundwater is less straightforward and requires that the oocysts move through soil and bedrock to reach the water table. The purpose of this study was to determine the relative concentration and infectivity of C. parvum oocysts released from manure and leached through columns of undisturbed, macroporous karst soil. Modeling the fate of oocysts in this system over time can provide baseline data for evaluating real world events. Substantially more oocysts leached from undisturbed soil columns than disturbed soil columns. Oocyst survival studies using BALB/c neonatal suckling mice showed that about 85% of oocysts were infective at the beginning of leaching experiments. The oocyst infectivity decreased to about 20% after 12 weeks of leaching from soil columns maintained at 10°C. Cool (10°C) temperatures appear to increase survivability and maintain infectivity of many oocysts for 3 months or longer. Cool temperatures also appear to increase rates of release of oocysts from manure and leaching through soil. This study demonstrated that leaching is an important mechanism of oocyst transport in karst soils where infiltration capacities are high and long, continuous macropores exist. Karst groundwater systems might be especially vulnerable to contamination by leached oocysts, because of the prevalence of shallow soils and rapid groundwater movement. Oocysts leaching from soils into the epikarst could accumulate and remain viable for months until hydrological conditions are right for flushing the oocysts into the conduit flow system.     

ASIANS,PACIFIC ISLANDERS,AND ETHNOBURBS IN AUCKLAND,NEW ZEALAND

ABSTRACT. Recent work on Asian ethnic minority immigrants to cities in the Anglophone Pacific Rim argues that their settlement patterns do not conform to those of earlier migrant streams. Instead of concentrating in high‐density, low‐quality, inner‐city housing, these new residents are moving directly to suburban areas where they form much less intensive concentrations—ethnoburbs—than has been typical of other culturally distinct migrant groups. We evaluate this thesis for Asian migrants in the Auckland metropolitan area, whose numbers more than quadrupled between 1991 and 2006. Their residential pattern is compared with that of Pacific Islanders also resident there, providing supporting evidence for the ethnoburb hypothesis.     

On Geographic and geography

New Zealand Geographic is one of a number of geographical magazines published in the English‐speaking world that make little or no reference to work by academic geographers. It recently launched a New Zealand Geographic Trust to promote research into ‘New Zealand's life, culture and sciences’ and collaborated with four other publishers of geographical magazines to raise awareness of climate change: the work of academic geographers is again ignored. This exclusion of academic and school geography from such enterprises raises important issues regarding the discipline's public profile in New Zealand and suggests the need for greater public engagement activity by the country's geographers.     

Using GIS and Dispersion Modelling Tools to Assess the Effect of the Environment on Health

A feasibility study in progress to integrate health and air quality information is presented. The methods of using integrated GIS and air quality dispersion modelling tools to assess the effect of the environment on health are discussed. The main aim is to model human personal exposure to air pollutants and compare the predictions to respiratory health data for asthmatics in a health telematics project. The MEDICATE project develops and tests the feasibility of using a health telematic system for asthmatics. Key to this is the determination of the real-time health (lung function) response to the ambient environment. For this, air quality information is related to respiratory measurements by modelling personal exposure through a GIS. The methods of integrating environmental modelling and assessment tools (GIS) in this case are examined. ESRI's ArcView is used to locate and compile environmental information about the patients' locations and lifestyles in the study areas (London and Barcelona). A dispersion modelling extension to ArcView, ADMS Urban, is used to interrogate the spatial environmental databases (e.g. emission inventories) to model air pollution concentrations. Patients' personal exposure is modelled by time-weighted estimates of their exposure to ambient air quality at each defined location. Lung function data can be compared on a time-wise basis with these air quality indicators to see if there is a relationship on an hourly, daily or lagged-day basis. The aim of this paper is to propose a methodology and discuss the integration and practicalities of using air quality assessment tools (inventories, dispersion modelling and a GIS) in assessing the impacts of the environment on human health.     

Geographic signatures of North American West Coast estuaries

West Coast estuaries are geologically young and composed of a variety of geomorphological types. These estuaries range from large fjords to shallow lagoons; from large to low freshwater flows. Natural hazards include E1 Niños, strong Pacific storms, and active tectonic activity. West Coast estuaries support a wide range of living resources: five salmon species, harvestable shellfish, waterfowl and marine birds, marine mammals, and a variety of algae and plants. Although populations of many of these living resources have declined (salmonids), others have increased (marine mammals). West Coast estuaries are also centers of commerce and increasingly large shipping traffic. The West Coast human population is rising faster than most other areas of the U.S. and Canada, and is distributed heavily in southern California, the San Francisco Bay area, around Puget Sound, and the Fraser River estuary. While water pollution is a problem in many of the urbanized estuaries, most estuaries do not suffer from poor water quality. Primary estuarine problems include habitat alterations, degradation, and loss; diverted freshwater flows; marine sediment contamination; and exotic species introductions. The growing West Coast economy and population are in part related to the quality of life, which is dependent on the use and enjoyment of abundant coastal natural resources.     

Recognition of down-valley translation in tidally influenced meandering fluvial deposits,Athabasca Oil Sands (Cretaceous), Alberta,Canada

The vast Athabasca Oil Sands of Alberta, Canada has an estimated resource of more than 1.7 trillion barrels of bitumen in-place, the majority of which is hosted in the Lower Cretaceous McMurray Formation. Despite its economical significance the depositional environment of the formation, and particularly the middle part that is the primary reservoir in most areas, is still a matter of considerable debate. These strata of interest are widely known to comprise fluvial and estuarine point bar deposits that were subject to varying degrees of marine influence. The orientation of point bar strata from the formation is tabulated and the majority is observed to dip paleo-basinward, to the north. This observation has proven difficult to explain by geologists attempting to build predictive models for the formation over the last two decades. However, the basinward-dipping point bar strata can be attributed to widespread down-valley translation of point bars in confined north-south oriented valleys, which have previously been delineated in the region. Differentiating the deposits of lateral point bar migration and down-valley translation in the rock record is not possible at the facies scale, and thus translated point bars have not been previously recognized or interpreted in the rock record, despite their prevalence in numerous modern fluvial valley systems. Their identification in the McMurray Formation has important implications for the delineation and development of Canada’s economically significant oil sands resources.