Contracts and member checks in qualitative research in human geography: reason for caution?

Contracts with, and member checks by, research participants are increasingly recommended in qualitative research in human geography. However, differences in qualitatively researching 'the powerful', as opposed to researching 'down' mean that contracts and member checks may need to be approached with caution regarding the former. The possibility of the censorship of critique by powerful research participants is exemplified in this article, and a number of more general dilemmas in qualitatively researching 'up' are also discussed. Finally, some choices which might help address possible difficulties in qualitatively researching the powerful are outlined.     

Hailstorm Loss Modelling and Risk Assessment in the Sydney Region,Australia

This paper summarises work undertaken at the Natural Hazards ResearchCentre with regard to the compilation, climatological analysis and lossmodelling application of hailstorm data for the greater Sydney region. Itdiscusses the results from two associated research areas: ENSO-relatedclimatological analysis of hailstorm data, and insurance sector orientedrisk assessment of hail losses in the Sydney basin. The two complementaryprojects led to the development of HailAUS, the first hail loss model for amajor urban area in Australia. The hazard occurrence module of the hailloss model is based on a comprehensive, good quality hail data set, whoseinterannual variability has previously been analysed with regard to the ENSOsignal. The paper presents the major results of the local hail data climatology,and outlines the structure of the hail loss model. The important practicalapplications that result from the collection and analysis of good qualityclimatological data are noted.     

Seasonal Forecasting for Climate Hazards: Prospects and Responses

One of the most promising developments for early warning of climate hazards is seasonal climate forecasting. Already forecasts are operational in many parts of the tropics and sub-tropics, particularly for droughts and floods associated with ENSO events. Prospects for further development of seasonal forecasting for a range of climatichazards are reviewed, illustrated with case studies in Africa, Australia, the U.S.A. and Europe. A critical evaluation of the utility of seasonal forecasts centres on vulnerability, communicationchannels, and effective responses. In contrast to short-term prediction, seasonal forecasts raise new issues of preparedness and the use of information.     

Application of short-wave infrared spectroscopy to define alteration zones associated with the Elura zinc–lead–silver deposit, NSW, Australia

Short-wave infrared reflectance spectra obtained from a Portable Infrared Mineral Analyser (PIMA) have been used to define alteration zones adjacent to base metal sulfide ore bodies at the Elura Mine, Cobar, Australia. The spectroscopic work identified white mica (sericite), chlorite and carbonates of hydrothermal origin in the alteration zones associated with the ore bodies. Weathering, alteration and ore zones can be discriminated by variations in the intensity and wavelength of relevant absorption features. Hydrothermal alteration is classified into four principal types, namely sericitic, silicic, chloritic and carbonate alteration. The first three types comprise overprinting hydrothermal assemblages of quartz, sericite, chlorite, ankerite, siderite, calcite and sulfides developed in strongly altered metasiltstone and slate of Early Devonian age, adjacent to the zinc–lead–silver mineralisation. An extensive zone of carbonate alteration, manifested as porphyroblasts of siderite in the host metasediments, is recognised beyond the zones of strong alteration. Spectral analysis is consistent with the mineralogical data obtained from XRD and XRF analyses and defines the limits of the alteration zones to distances of about 80 m around the ore bodies. The study demonstrates the potential for spectral analysis to assist with drill hole logging and the identification of alteration zones as part of mineral exploration and development programs.     

The Palaeozoic tectono-metallogenic evolution of the northern Tasman Fold Belt System, Australia: Interplay of subduction rollback and accretion

The Tasman Fold Belt System in eastern Australia provides a record of the Palaeozoic geological history and growth of the Australian continent along the proto-Pacific margin of Gondwana inboard of an extensive and long-lived subduction system. The Hodgkinson and Broken River provinces represent prominent geological elements of this system and together form the northern Tasman Fold Belt System. Geochronological age dating of the timing of gold formation in the Amanda Bel Goldfield in the Broken River Province and the Hodgkinson Goldfield in the Hodgkinson Province provides constraints on the occurrence of a deformation and mineralisation episode in the Late Devonian–Early Carboniferous. Integration of these newly-obtained data with petrogenetic constraints and a time–space evaluation of the geological evolution of the Hodgkinson and Broken River provinces, as well as other terranes in the northern Tasman Fold Belt System, allows for the development of a geodynamic model for the Palaeozoic evolution of the northern Tasman Fold Belt System. Our model indicates that three cycles of extension–contraction occurred during the Palaeozoic evolution of the northern Tasman Fold Belt System. Episodes of extension were controlled by rollback of the subduction system along the proto-Pacific margin of Gondwana, whereas episodes of contraction resulted from accretion following the arrival of positively buoyant segments (i.e., micro-continental blocks/oceanic plateaus) at the subducting trench.Our composite interpretative model on the geodynamic evolution of the northern Tasman Fold Belt System integrates the timing of the development of mineral deposits throughout this part of the system and provides a significant advancement in the understanding of Palaeozoic geodynamics along the margin of Gondwana in northeast Australia and allows comparison with the southern part of the Tasman Fold Belt System.     

Segregation and Residential Mobility of Vietnamese Immigrants in Brisbane,Australia

The study focuses on residential mobility propensities of Vietnamese immigrants in the city of Brisbane, Australia, as a principal force contributing to the persistence or change of ethnic residential segregation over time. Using 1990 survey data, discrete-time logit models are estimated to assess the effects of locational, contextual, and personal characteristics on the likelihood of changing residence within the city. The results indicate that locational variables operate in such a way that the most dominant Vietnamese neighborhood in Brisbane increases its prominence even further, while secondary Vietnamese clusters are likely to weaken. The results also indicate that initial settlement conditions are important for the first move only, whereas personal attributes contribute to variations in mobility propensities primarily in the second move. This implies that the composition of the immigrant population potentially influences the speed at which changes in ethnic residential patterns will occur in urban areas.     

EXTREME RESERVOIR SEDIMENTATION IN AUSTRALIA:A REVIEW

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The unique nature in ore composition,geological backgroudd and metallogenic mechanism of non-conventional superlarge ore deposits: A preliminary discussion

The new plants documented here, including a representative of the trimerophytesPsilophyton primitiuum sp. nov., a questionable rhyniophyte or trimerophyteHedeia sinica sp. nov., a prelycopodBragwanathia sp. and two species of zosterophyllophytes,Zosterophyllum australianum Lang and Cookson 1930 and2. sp. 1, from the Posongchong Formation of southeastern Yunnan, China, add to the known floral diversity of the Early Devonian of this region. Two sections of the Posongchong Formation, Changputang section of Wenshan district and Gegu section of Mengzi district also are introduced. After comparing the plants with those of the coeval flora of Australia and considering the data of recent paleocontinental reconstructions, the authors suggest that there is a northeastern Gondwana phytogeographic unit during the early Devonian comprising Australia, South China Block and perhaps Shan-Thai Block. The similarity of the floral component between Australia and South China is discussed. Because both Australia and South China also have dominant or endemic taxa, each might be recognized as a subunit, separately characterized byHedeia for Australia andEophyllophyton for South China. Project supported by the National Natural Science Foundation of China (Grant Nos. 49372075 and 49742004)     

Pliocene aridity and Neogene landscape evolution recorded by a fluvial sediment system (Campaspe Formation) in northeast Queensland

Campaspe Formation, a surficial, fluviatile, sand-dominated unit, is extensively developed in the Charters Towers region of north Queensland where it covers an area of 11 000 km², overlying Paleozoic basement and erosional remnants of Paleogene Southern Cross Formation. In the northern part of its distribution, it is interlayered with, and overlain by, flows of Nulla Basalt. It is dated as mid-Pliocene, based on the 3.48 Ma age of the Myrrilumbing Flow interlayered with its upper part, an antiquity consistent with thin ferricrete locally developed at its surface. The formation defines the Campaspe Surface at an elevation of 200–440 m in the present landscape, falling gently from upland to the west towards the current channel of the Burdekin River. This surface is a relict alluvial plain little incised by easterly flowing tributaries of the Burdekin River and has survived, essentially intact, from the early Pliocene. Geometry of the formation is established from some 2000 mineral exploration drill holes and seismic profiling. It has an average thickness of some 60 m, reaching a maximum of over 200 m. It blankets a pre-existing, low relief landscape in which a basement ridge divides it into two sub-basins that mirror the present drainage. The formation consists of poorly sorted sandstone with minor conglomerate and siltstone, and contains paleosol horizons with associated calcrete. Matrix supported sandstone in the succession, indicates deposition in part from hyperconcentrated flows. Sandstones generally show poorly defined planar layering as typical of ephemeral overbank and terminal splay sediment bodies but beds with cross-lamination, indicating fluvial channel bed forms, are also present. They are characterised by pore-filling silt and mud, largely emplaced by post-depositional infiltration, such that the unit produces essentially no groundwater. Facies attributes are consistent with fluvial deposition in ephemeral, dry climate, distributary system, with inefficient cross-drainage discharge that induced aggradation, resulting in a substantial sediment body perched in the landscape. Framework grain compositions show the formation to be mineralogically mature, representing erosional debris derived from intense weathering in an earlier climatic regime recorded, at least in part, by duricrust developed in the fluviatile–lacustrine Southern Cross Formation of Paleogene age. Such duricrust intervals are now upstanding in the landscape, representing erosional remnants from inverted relief developed in a mid-Cenozoic, pluvial, landscape cycle. Paleoclimatic signature of the Campaspe Formation extends the record of Pliocene aridity, widely recognised elsewhere in Australia, to northeast Queensland. In large part the landscape of the Charters Towers district is relict from the early Pliocene and is in the process of readjusting to more pluvial climatic regimes. By implication, Pliocene aridity has, on a small scale, exerted a strong influence on the present physiography of Australian landscapes.