Platinum and palladium mobility in supergene environment: The residual origin of the Pirogues River mineralization, New Caledonia     

D. Traor  A. Beauvais  T. Aug  F. Chabaux  J.-C. Parisot  M. Cathelineau  C. Peiffert  F. Colin 《Journal of Geochemical Exploration》2006,88(1-3):350

Eluvial concentration of platinum-group minerals (PGM) has developed in the south of New Caledonia, from the weathering of a mafic and ultramafic cumulate. The platinum/palladium (Pt/Pd) ratio evolution from the bottom to the top of the weathering profile indicates a chemical mobilization of Pd in supergene environment. The examination by scanning electron microscopy of the residual PGM collected in the weathering profile and their chemical characterization by electronic microprobe show a preservation of the structure and chemical signature (in the core of the grains) of the fresh PGM. This clearly demonstrates that the PGM studied here are residual and are affected by dissolution process.  相似文献   

The political-economy of Blair’s “New Regional Policy”     

John Harrison   《Geoforum》2006,37(6):932-943

The “region” and “regional change” have been elusive ideas within political and economic geography, and in essence require a greater understanding of their dynamic characteristics. Trailing in the backwaters of the devolution to the Celtic nations of Britain, the contemporary era of New Labour’s political-economic ideology, manifest through “third-way” governance in England places the region and its functional capacity into the heart of geographical inquiry. Drawing upon a new regionalist epistemology, this paper seeks to recover a sense of (regional) political economy through a critical investigation of the development and formulation of Blair’s “New Regional Policy” (NRP). I address how New Labour has attempted to marry economic regionalisation on the one hand, and democratic regionalism on the other. This paper specifically questions the wisdom of such a marriage of politically distinct ideologies through a critical investigation of the underlying contradictions of their strategy from both a theoretical and empirical standpoint. Demonstrated both in the North East “no” vote in 2004, and in the post-mortem undertaken by the ODPM Select Committee in 2005, the paper illustrates how a loss of political drive gradually undermined the capacity of devolution to deliver in England. Finally, I argue that through the lens of the NRP we can speculate on some of the wider issues and implications for the study of regional governance.  相似文献   

Timing of the late-glacial climate reversal in the Southern Hemisphere using high-resolution radiocarbon chronology for Kaipo bog, New Zealand     

Irka Hajdas  David J. Lowe  Georges Bonani 《Quaternary Research》2006,65(2):340-345

The pattern of climate change in the Southern Hemisphere during the Younger Dryas (YD) chronozone provides essential constraint on mechanisms of abrupt climate change only if accurate, high-precision chronologies are obtained. A climate reversal reported previously at Kaipo bog, New Zealand, had been dated between 13,600 and 12,600 cal yr B.P. and appeared to asynchronously overlap the YD chron, but the chronology, based on conventionally radiocarbon-dated bulk sediment samples, left the precise timing questionable. We report a new high-resolution AMS ¹⁴C chronology for the Kaipo record that confirms the original chronology and provides further evidence for a mid-latitude Southern Ocean cooling event dated between 13,800 and 12,400 cal yr B.P. (2σ range), roughly equivalent to the Antarctic Cold Reversal.  相似文献   

Magnitudes, spatial scales and processes of environmental antimony mobility from orogenic gold–antimony mineral deposits, Australasia     

P. M. Ashley  D. Craw  M. K. Tighe  N. J. Wilson 《Environmental Geology》2006,51(4):499-507

Antimony (Sb) is strongly concentrated into hydrothermal mineral deposits, commonly with gold, in metasedimentary sequences around the Pacific Rim. These deposits represent potential point sources for Sb in the downstream environment, particularly when mines are developed. This study documents the magnitude and scale of Sb mobility near some mineral deposits in Australia and New Zealand. Two examples of New Zealand historic mining areas demonstrate that natural groundwater dissolution of Sb from mineral deposits dominates the Sb load in drainage waters, with Sb concentrations between 3 and 24 μg/L in major streams. Mine-related discharges can exceed 200 μg/L Sb, but volumes are small. Sb flux in principal stream waters is ca 1–14 mg/s, compared to mine tunnel fluxes of ca 0.001 mg/s. Dissolved Sb is strongly attenuated near some mine tunnels by adsorption on to iron oxyhydroxide precipitates. Similar Sb mobilisation and attenuation processes are occurring downstream of the historic/active Hillgrove antimony–gold mine of New South Wales, Australia, but historic discharges of Sb-bearing debris has resulted in elevated Sb levels in stream sediments (ca 10–100⁺ mg/kg) and riparian plants (up to 100 mg/kg) for ca 300 km downstream. Dissolution of Sb from these sediments ensures that river waters have elevated Sb (ca 10–1,000 μg/L) over that distance. Total Sb flux reaching the Pacific Ocean from the Hillgrove area is ca 8 tonnes/year, of which 7 tonnes/year is particulate and 1 tonne/year is dissolved.  相似文献   

The Geography of Certified Trade‐Induced Manufacturing Job Loss in New England*     

John T. Bowen 《The Professional geographer》2006,58(3):249-265

The article analyzes patterns in the distribution of manufacturing job losses that have been certified as trade‐induced by the U.S. Department of Labor. Spatial patterns in the likelihood of job loss are examined in the United States for the period from 1994 to 2002, with particular emphasis on county‐level patterns in New England. The findings demonstrate that the pattern of losses was correlated with measures of economic vitality and competitiveness including per capita income, educational attainment, occupational structure, and inventiveness. These results suggest that trade‐induced deindustrialization is borne most heavily by places ill‐equipped to compete in a more open, integrated international economy.  相似文献   

兖州矿区煤中某些微量元素的赋存状态研究   总被引：6，自引：8，他引：6  

刘桂建  杨萍玥  彭子成  王桂梁  曹增会 《地球化学》2002,31(1):85-90

微量元素的赋存状态决定其在煤的加工利用过程中释放的难易程度和毒性，弄清其在煤中的赋存状态，对准确评价元素的工艺性能、环境影响、作为副产品的可能性以及在地质意义上都是十分重要的。分析了微量元素在煤中的有机亲合性，采用数理统计方法，求得了微量元素与煤中有机显微组分、三态硫、灰分之间的相关性，并在浮沉实验的基础上，分析了微量元素的存在状态，通过研究向知，Ge、Ga、U、V、Cu、Th、Pb和Zn主要以无机态存在于煤中，F和Cl可能以有机态存在为主，As无机态和有机态存在的机率相似。  相似文献   

Interpretation of seismic and potential field data from western New York State and Lake Ontario     

Khaled Ouassaa  David A. Forsyth   《Tectonophysics》2002,353(1-4)

Lithoprobe and industry seismic profiles have furnished evidence of major zones of easterly dipping Grenville deformed crust extending southwest from exposed Grenville rocks north of Lake Ontario. Additional constraints on subsurface structure limited to the postulated Clarendon–Linden fault system south of Lake Ontario are provided by five east–west reflection lines recorded in 1976. Spatial correlations between seismic structure and magnetic anomalies are described from both Lake Ontario and the newly reprocessed New York lines.In the Paleozoic to Precambrian upper crust, the New York seismic sections show: (1) An easterly thickening wedge of subhorizontal Paleozoic strata unconformably overlying a Precambrian basement whose surface has an apparent regional easterly dip of 1–2°. Minor apparent normal offsets, possibly on the order of tens of meters, occur within the Paleozoic section. The generally poorly reflective unconformity may be locally characterized by topographic relief on the order of 100 m; (2) Apparent local displacement on the order of 90 m at the level of the Black River Group diminishes upward to little or no apparent offset of Queenston Shale; (3) Within the limited seismic sections, there appears to be no evidence that the complete upper crustal section is vertically or subvertically offset; (4) Dipping structure in the Paleozoic strata (15° to 35°) resembles some underlying Precambrian basement elements; (5) The surface continuity of inferred faults constituting the Clarendon–Linden system is not strongly supported by the seismic data.Beneath the Paleozoic strata, the seismic sections show both linear and arcuate reflector geometry with easterly apparent dips of 15° to 35° similar to the deep structures imaged on seismic lines from nearby Lake Ontario and on Lithoprobe lines to the north. The similarity supports an extension of easterly dipping Central Metasedimentary Belt structures of the Grenville orogen from southern Ontario to beneath western New York State.From a comparison of the magnetic and gravity fields with the New York seismic sections, we suggest: (1) The largely nonmagnetic Paleozoic strata appear to contribute negligibly to magnetic anomalies. Seismically imaged fractures in the New York Paleozoic strata appear to lie mainly west of a positive gravity anomaly. The relationship between magnetic and gravity anomalies and the changes in the geometry of interpreted Precambrian structures remains enigmatic; (2) North to northeast trending curvilinear magnetic and gravity anomalies parallel, but are not restricted to the principal trend of the postulated Clarendon–Linden fault system. Paleozoic fractures of the Clarendon–Linden system may partly overlie a southward extension of the Composite Arc Belt boundary zone.  相似文献   

Stresses and strains in a twisted subduction zone—Fiordland, New Zealand     

Martin Reyners  Russell Robinson  Aasha Pancha  Peter McGinty 《Geophysical Journal International》2002,148(3):637-648

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Relationship between crustal finite strain and seismic anisotropy in the mantle, Pacific–Australia plate boundary zone, South Island, New Zealand     

Timothy A. Little  Martha K. Savage  Basil Tikoff 《Geophysical Journal International》2002,151(1):106-116

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Planning a Prosperous Sydney: The challenges of planning urban development in the new urban context     

Pauline McGuirk  Phillip O'Neill 《The Australian geographer》2002,33(3):301-316

Since their post-war inception, Sydney's metropolitan plans have tended to be overtaken by the social, economic and environmental conditions they have had to confront. The depth and scope of Sydney's recent urban transformation threatens again to overtake metropolitan planning capacity creating, in the context of competitive globalisation, a potentially significant market disadvantage for the city, not to mention poor urban development outcomes. This paper reviews Sydney's post-war metropolitan planning strategies, examining the social and economic contexts and the policy paradigms in which they have been framed, in order to draw out the lessons to be learned from their successes and failures. We argue that future success in planning urban development will rely on richly informed and fine-grained understanding of the complex spatial outcomes of Sydney's ever-deeper global integration. Only such fine-grained understanding can empower metropolitan planning to be responsive to the evolving challenges of managing development in the contemporary urban context.  相似文献