The provenance of Australian uranium ore concentrates by elemental and isotopic analysis     

Elizabeth Keegan  Stephan Richter  Ian Kelly  Henri Wong  Patricia Gadd  Heinz Kuehn  Adolfo Alonso-Munoz 《Applied Geochemistry》2008

Elemental and isotopic ratio analyses of U ore concentrate samples, from the 3 operating U mining facilities in Australia, were carried out to determine if significant variations exist between their products, thereby allowing the U ore concentrate’s origin to be identified. Elemental analyses were conducted using inductively coupled plasma mass spectrometry (ICP-MS) and X-ray fluorescence spectrometry (XRF). Lead isotope ratios were measured using ICP-MS and U isotope analyses were conducted using thermal ionisation mass spectrometry (TIMS). Minute quantities of sample, such as that obtained from a swipe, were also examined for elemental concentrations using secondary ion mass spectrometry (SIMS). The results of multivariate statistical analysis show clear patterns in the trace elemental composition of the processed U ores, indicating that it is possible to use this feature as a unique identifier of an Australian U ore concentrate’s source. Secondary ion mass spectrometry analyses also allow individual particles to be differentiated using this ‘fingerprinting’ technique. Isotope ratios determined using TIMS reveal that there is a significant difference in the n(²³⁴U)/n(²³⁸U) isotope ratio between the U ore concentrate from each mine.  相似文献   

Holocene climate and environmental history of East Greenland inferred from lake sediments     

Amanda R. Lusas  Brenda L. Hall  Thomas V. Lowell  Meredith A. Kelly  Ole Bennike  Laura B. Levy  William Honsaker 《Journal of Paleolimnology》2017,57(4):321-341

Prediction of future Arctic climate and environmental changes, as well as associated ice-sheet behavior, requires placing present-day warming and reduced ice extent into a long-term context. Here we present a record of Holocene climate and glacier fluctuations inferred from the paleolimnology of small lakes near Istorvet ice cap in East Greenland. Calibrated radiocarbon dates of organic remains indicate deglaciation of the region before ~10,500 years BP, after which time the ice cap receded rapidly to a position similar to or less extensive than present, and lake sediments shifted from glacio-lacustrine clay to relatively organic-rich gyttja. The lack of glacio-lacustrine sediments throughout most of the record suggests that the ice cap was similar to or smaller than present throughout most of the Holocene. This restricted ice extent suggests that climate was similar to or warmer than present, in keeping with other records from Greenland that indicate a warm early and middle Holocene. Middle Holocene magnetic susceptibility oscillations, with a ~200-year frequency in one of the lakes, may relate to solar influence on local catchment processes. Following thousands of years of restricted extent, Istorvet ice cap advanced to within 365 m of its late Holocene limit at ~AD 1150. Variability in the timing of glacial and climate fluctuations, as well as of sediment organic content changes among East Greenland lacustrine records, may be a consequence of local factors, such as elevation, continentality, water depth, turbidity, and seabirds, and highlights the need for a detailed spatial array of datasets to address questions about Holocene climate change.  相似文献   

The geomagnetic field over the past 5 million years     

Peter Kelly  David Gubbins 《Geophysical Journal International》1997,128(2):315-330

The modern geomagnetic field is usually expressed as a spherical harmonic expansion. Although the palaeomagnetic record is very incomplete in both space and time, sufficient data are available from a span of ages to generate time-averaged spherical harmonic field models with many degrees of freedom. Here three data sets are considered: directional measurements from lavas, inclination measurements from ocean sediments, and intensity measurements from lavas. Individual data are analysed, as well as site-averages, using the same methods that have been developed for the modern field, to give models for the past 5 Myr. The normal-polarity field model has an axial-dipole intensity similar to that of the modern-day field, whilst the equatorial-dipole component is very much smaller. The field is not axisymmetric, but shows flux concentrations at the core's surface under Canada and Siberia similar to those observed in the field over historical timescales. Tests on synthetic data show that it is unlikely that these similarities result from the overprinting of the palaeomagnetic field due to inadequate cleaning of the samples. The reverse-polarity field model does not show such obvious features, but this may be due to the sparsity of the data.
The patterns observed in the normal-polarity field, with persistent features in the northern hemisphere and a smooth southern hemisphere, could be explained if the present pattern of secular variation is typical of the past several million years. This would reveal itself as large variations over time in the direction of the magnetic vector in regions of high secular variation, with relatively little change over quieter regions. However, we have been unable to find any evidence for a geographical pattern of secular variation in the data.  相似文献   

Reply by authors to A. McLellan and A. Filiatrault     

H. C. Tsai  J. M. Kelly 《地震工程与结构动力学》1991,20(3):297-298

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Kriging with imprecise (fuzzy) variograms. II: Application   总被引：2，自引：0，他引：2  

A. Bardossy  I. Bogardi  W. E. Kelly 《Mathematical Geology》1990,22(1):81-94

The geostatistical analysis of soil liner permeability is based on 20 measurements and imprecise prior information on nugget effect, sill, and range of the unknown variogram. Using this information, membership functions for variogram parameters are assessed and the fuzzy variogram is constructed. Both kriging estimates and estimation variances are calculated as fuzzy numbers from the fuzzy variogram and data points. Contour maps are presented, indicating values of the kriged permeability and the estimation variance corresponding to selected membership values called levels.  相似文献   

Barotropic,subtidal exchange between Calcasieu Lake and the Gulf of Mexico     

J. M. Lee  W. J. Wiseman  F. J. Kelly 《Estuaries and Coasts》1990,13(3):258-264

Long-term measurements of flow through Calcasieu Pass, Louisiana, are compared to water level variations within Calcasieu Lake, Louisiana. Except during periods of freshets driven by local rainfall, the exchange is shown to be predominantly barotropic. A simple wind-driven model accounts for the observed phase relations between wind, current, and water level.  相似文献   

The effects of tributyltin within aThalassia seagrass ecosystem     

John R. Kelly  Suzanne N. Levine  Linda A. Buttel  Kelly A. Carr  David T. Rudnick  R. Dana Morton 《Estuaries and Coasts》1990,13(3):301-310

Flow-through seagrass core microcosms were used to examine responses of species and processes to a logarithmic gradient of dosing with¹⁴C-labeled tributyltin-chloride (TBT-CI). Experiments involved delivery of TBT-CI to the water column of replicate cores of a treatment (n=16) once per week; one-half of the cores were sacrificed after 3 wk of dosing, the others were dosed for 6 wk. Initial water column concentrations for the three treatments averaged 0.205, 2.23, and 22.21 μg I^?1, expressed as the TBT⁺ cation, but these concentrations dropped rapidly. Retained¹⁴C tracer, an estimate of total organotin species, was distributed to sediments, plants, and other biological tissues, all of whose tracer concentrations increased with time. Measures to indicate responses of both autotrophic and heterotrophic organisms were made; in general, treatment effects were demonstrable statistically only at the highest dose level. Accumulation of chlorophyll and biomass on glass slides was highest when suspended for the entire experiment in the water of the highest treatment; this unexpected result was perhaps an indirect effect related to reduced grazing activity in the microcosms. The highest dose of TBT-CI resulted in virtual population mortality of a few macrobenthic species and decreased loss of plant material in litter bags, both demonstrated within the first 3 wk of dosing. Reduced litter loss was coincident with mortality of an amphipod (Cymadusa compta) capable of shredding plant material, and a causal relation between the two effects is plausible. Thus, if concentrated to similar levels in aThalassia bed, TBT⁺ may have direct species-level effects and process-level effects, potentially causing ecosystem change via disruption of a species-process linkage influential in seagrass detrital food web dynamics.  相似文献   

Identifying ‘place’ in place branding: core and periphery in Brisbane’s “New World City”     

Kelly Greenop  Sébastien Darchen 《GeoJournal》2016,81(3):379-394

Brisbane is Australia’s third largest city, and capital of the state of Queensland. It has a sprawling urban footprint and impending connections to neighbouring metropolises, said to create a ‘200 km city’. The governing body of Brisbane controls the largest municipality in Australia, with unrivalled opportunity to influence both urban planning and marketing for the CBD and suburbs. Brisbane is home to over one million people, and its population has grown rapidly over the past decades, doubling in the past 40 years. Brisbane represents the quintessential city with an emerging quest for urbanity, both in brand and physical form. The relationships between the city’s urban planning and its branding is not well examined, despite clear entanglement between these two strategies. We use a case-study analysis of both Brisbane City (which is glossed as the Central Business District) and an outer-suburban area, Inala, to interrogate how urban identities and brand are being constructed in relation to their social settings and governance, with particular reference to the importance of city branding and its relationship to planning strategies. The manifestation of branding and relationship to place qualities at the core and on the periphery of Brisbane are examined, with relevance for other rapidly growing, ambitious cities. The focus of Brisbane’s push for urbanity is on the city centre, and is not representative of the typical suburban condition, nor of many cities dominated by suburban forms. An analysis of place brand, planning strategies and resident’s responses to place, from planning, architectural and anthropological perspectives are offered, as an alternative reading of place brand from the marketing dominated approach usually favoured in branding analysis. We make recommendations to incorporate a more complete version of place in the construction of a “genuine” urbanity. We argue that the recognition of resident-centred place identity in place branding will produce more socially sustainable places, as well as more authentic city brands.  相似文献   

Commentary on “Spatial Social Network Analysis of Resource Access in Rural South Africa”     

Gregory Kelly 《The Professional geographer》2016,68(2):299-300

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Report of an excursion to Ipswich and Claydon: Saturday,July 3rd, 1915     

P.G.H. Boswell 《Proceedings of the Geologists' Association. Geologists' Association》1915,26(5):327-330

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