Attribution of uranium ore concentrates using elemental and anionic data   总被引：1，自引：0，他引：1  

Elizabeth Keegan  Maria Wallenius  Klaus Mayer  Zsolt Varga  Gert Rasmussen 《Applied Geochemistry》2012

The capability to correctly identify the geological or geographical source of unknown uranium ore concentrates (UOCs) has obvious nuclear security benefits. This paper reports on a scoping study where the trace elemental and anionic compositions of 24 UOC samples, sourced mainly from mines in Australia and Canada, were examined for their ability to allow attribution of the sample to a particular geological U deposit type or to a particular geographical source. Results of statistical analysis using canonical analysis of principal coordinates (CAP) showed that samples originating from certain U ore deposit types, especially phosphorite and quartz-pebble conglomerate, contained a distinct impurity composition. Samples grouped according to their geographical region of origin appeared to contain distinctive impurities in certain cases (Elliot Lake and Bancroft, Ontario). The key impurities responsible for differentiating groups of samples from a particular geological deposit type were identified and the use of certain impurities as signatures of processing history is discussed. The methodology described in this scoping study provides a promising approach for more comprehensive databases.  相似文献   

Spatial polarization and dynamic pathways of Foreign Direct Investment in China 1990–2009     

Simon Xiaobin Zhao  Roger C.K. Chan  Neo Ying Ming Chan 《Geoforum》2012,43(4):836-850

The spatial and sectoral distribution of Foreign Direct Investment (FDI) in China has changed dramatically in the past two decades. FDI was largely concentrated in the Pearl River Delta (PRD) and other Southern Coastal provinces in early stages and shifted to the Yangtze River Delta (YRD) and the Bohai Economic Rim (BER) sequentially in later stages. It created unique and dynamic paths of the spatial evolution of FDI in China. Although many provinces have received relatively more FDI since the late 2000s, Guangdong and Jiangsu are still the two major recipients of FDI in China, demonstrating and over-arching polarization process. Furthermore, most FDI in China has been in the manufacturing sector, making China well-known as the “World Factory of Manufacturing”. This paper analyses the most recent trends, characteristics and patterns of FDI in China. It portrays the factors that determined the investment location and the dynamic pathways of different kinds of FDI. This paper also foresees the possible changes in spatial and sectoral distribution of FDI in the near future and provides policy suggestions for both China and other developing countries in seeking new FDI inflows and transforming their industrial structures and economies in this particular phase of globalization.  相似文献   

Radiocarbon analysis of halophilic microbial lipids from an Australian salt lake     

P. Sargent Bray  Claudia M. Jones  Stewart J. Fallon  Jochen J. Brocks  Simon C. George 《Quaternary Research》2012,77(1):104-109

Assigning accurate dates to hypersaline sediments opens important terrestrial records of local and regional paleoecologies and paleoclimatology. However, as of yet no conventional method of dating hypersaline systems has been widely adopted. Biomarker, mineralogical, and radiocarbon analyses of sediments and organic extracts from a shallow (13 cm) core from a hypersaline playa, Lake Tyrrell, southeastern Australia, produce a coherent age-depth curve beginning with modern microbial mats and extending to ~ 7500 cal yr BP. These analyses are furthermore used to identify and constrain the timing of the most recent change in hydrological regime at Lake Tyrrell, a shift from a clay deposit to the precipitation of evaporitic sands occurring at some time between ~ 4500 and 7000 yr. These analyses show the potential for widespread dating of hypersaline systems integrating the biomarker approach, reinforce the value of the radiocarbon content of biomarkers in understanding the flow of carbon in modern ecologies, and validate the temporal dimension of data provided by biomarkers when dating late Quaternary sediments.  相似文献   

Reconstruction of the late Quaternary paleoenvironments of the Nussloch loess paleosol sequence,Germany, using n-alkane biomarkers     

Michael Zech  Simon Rass  Björn Buggle  Manfred Löscher  Ludwig Zöller 《Quaternary Research》2012,78(2):226-235

This study contributes to the paleoenvironmental reconstruction of the loess–paleosol sequence of Nussloch, Germany, by using n-alkanes as plant leaf-wax-derived lipid biomarkers. We found that n-alkane patterns and concentrations in the Saalian loess and the last interglacial Eemian paleosol of Nussloch point to very strong degradation and prevailing deciduous vegetation. Degradation effects in the overlying paleosols and loess layers are less pronounced and allow for the application of an end-member mixing model to estimate vegetation changes semi-quantitatively. Our findings highlight the potential for the interpretation of degradation-corrected n-alkane ratios. n-Alkane modelling results for loess layers, paleosols and an in-filled paleochannel dated to ~ 60–32 ka suggest that up to ~ 50% of the n-alkanes were derived from deciduous trees or shrubs. This finding is in agreement with the abundant occurrence of wood fragments and indicates a highly variable and dynamic landscape dominated by tundra shrubland. On the other hand, deciduous trees or shrubs did not contribute significantly to the soil organic matter in the late Weichselian loess layers and the intercalated Gelic Gleysols (~ 32–18 ka).  相似文献   

The P–V–T equation of state of CaPtO3 post-perovskite     

Simon A. Hunt  Alex Lindsay-Scott  Ian G. Wood  Michael W. Ammann  Takashi Taniguchi 《Physics and Chemistry of Minerals》2013,40(1):73-80

Orthorhombic post-perovskite CaPtO₃ is isostructural with post-perovskite MgSiO₃, a deep-Earth phase stable only above 100 GPa. Energy-dispersive X-ray diffraction data (to 9.4 GPa and 1,024 K) for CaPtO₃ have been combined with published isothermal and isobaric measurements to determine its P–V–T equation of state (EoS). A third-order Birch–Murnaghan EoS was used, with the volumetric thermal expansion coefficient (at atmospheric pressure) represented by α(T) = α₀ + α₁(T). The fitted parameters had values: isothermal incompressibility, $ K_{{T_{0} }} $  = 168.4(3) GPa; $ K_{{T_{0} }}^{\prime } $  = 4.48(3) (both at 298 K); $ \partial K_{{T_{0} }} /\partial T $  = ?0.032(3) GPa K^?1; α₀ = 2.32(2) × 10^?5 K^?1; α₁ = 5.7(4) × 10^?9 K^?2. The volumetric isothermal Anderson–Grüneisen parameter, δ _T , is 7.6(7) at 298 K. $ \partial K_{{T_{0} }} /\partial T $ for CaPtO₃ is similar to that recently reported for CaIrO₃, differing significantly from values found at high pressure for MgSiO₃ post-perovskite (?0.0085(11) to ?0.024 GPa K^?1). We also report axial P–V–T EoS of similar form, the first for any post-perovskite. Fitted to the cubes of the axes, these gave $ \partial K_{{aT_{0} }} /\partial T $  = ?0.038(4) GPa K^?1; $ \partial K_{{bT_{0} }} /\partial T $  = ?0.021(2) GPa K^?1; $ \partial K_{{cT_{0} }} /\partial T $  = ?0.026(5) GPa K^?1, with δ _T  = 8.9(9), 7.4(7) and 4.6(9) for a, b and c, respectively. Although $ K_{{T_{0} }} $ is lowest for the b-axis, its incompressibility is the least temperature dependent.  相似文献   

Jilin-Heilongjiang High-Pressure Metamorphic Belt: Evidence and Tectonic Implications     

ZHOU Jianbo  Simon A WILDE  HAN Jie 《《地质学报》英文版》2013,87(Z1):534-534

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Detritalzircon Geochronology and Hf Isotope of Triassic Sandstones in Inner Mongolia, China: Implications for the Provenance and Post-Accretionary Crustal Evolution of the Southeastern Central Asian Orogenic Belt     

LI Shan  Simon A. WILDE  HE Zhengjun  JIANG Xiaojun  LIU Renyan  ZHAO Lei 《《地质学报》英文版》2013,87(Z1):311-312

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Command and control cities in global space-economy before and after 2008 geo-economic transition     

Ernest Ka Shing LEE  Simon Xiaobin ZHAO 《中国地理科学(英文版)》2012,22(3):334-342

The global economic downturn caused primarily by the US sub-prime mortgage crisis in 2007 engendered revenue loss of the multinational corporations.Existing studies have yet to depict the detrimental impacts on city’s command and control functions induced by the sub-prime mortgage crisis together with its residual wave of global economic recession on the global spatial economy.Recent and previous studies have produced an ’instant history’ of the global spatial economy before the global economic downturn undermines the global economy in late 2008.However,the waxes and wanes of major cities’ command and control functions on the global economic arena before and after the outbreak of financial crisis and its associated geo-economic transitions are still poorly understood.This paper attempts to contribute a new set of customized data to update and fill in the gap in the literature with the investigation of the command and control functions of cities around the world from 2005 to 2009.Particular attentions are paid to the time-space relationship of the geo-economic transition that can capture the recent historical images of the command and control situation of different cities in the world.  相似文献   

Guest Editor’s Acknowledgements     

Simon Xiaobin Zhao 《中国地理科学(英文版)》2012,(3):342

This special column was the outcomes of the Public Forum on China’s Spatial Strategic Planning and Development in the National 12th Five-year Plan held at the University of Hong Kong (HKU) in April 2011.The Public Forum was jointly organized by the International  相似文献   

Centennial records of lead contamination in northern Atlantic bivalves (Arctica islandica)     

Krause-Nehring J  Brey T  Thorrold SR 《Marine pollution bulletin》2012,64(2):233-240

In the study, we establish centennial records of anthropogenic lead pollution at different locations in the North Atlantic (Iceland, USA, and Europe) by means of lead deposited in shells of the long-lived bivalve Arctica islandica. Due to local oceanographic and geological conditions we conclude that the lead concentrations in the Icelandic shell reflect natural influxes of lead into Icelandic waters. In comparison, the lead profile of the US shell is clearly driven by anthropogenic lead emissions transported from the continent to the ocean by westerly surface winds. Lead concentrations in the European North Sea shell, in contrast, are dominantly driven by local lead sources resulting in a much less conspicuous 1970s gasoline lead peak. In conclusion, the lead profiles of the three shells are driven by different influxes of lead, and yet, all support the applicability of Pb/Ca analyses of A. islandica shells to reconstruct location specific anthropogenic lead pollution.  相似文献