铜、镍、铂族元素地球化学性质及其在幔源岩浆起源、演化和岩浆硫化物矿床研究中的意义

Ni、Cu和PGE具有不同于其他微量元素的特殊的地球化学性质,这些特殊的性质使得它们在幔源岩浆起源和演化以及岩浆硫化物矿床的成因研究中具有不可替代的作用。在S不饱和的条件下,Ni、Os、Ir和Ru具有相容元素的特性,而Cu和Pd是强不相容元素,因此,它们在玄武岩浆分离结晶过程中常常发生分异。一旦体系达到S饱和,这些元素则会强烈地进入硫化物熔浆,特别是PGE具有极高的硫化物熔浆/硅酸盐熔浆分配系数,极微量的硫化物熔离便可导致残余岩浆中PGE的显著亏损,因此,PGE是玄武岩浆硫化物熔离作用最敏感的示踪元素。硫化物熔离和成矿实质上是幔源岩浆特殊演化过程的结果,所以,Ni,Cu和PGE的特殊性质可用来探讨岩浆硫化物成矿的关键控制因素。Ni、Cu和PGE具有不同的单硫化物固溶体/硫化物熔浆分配系数,因此,它们也是硫化物熔浆结晶分异的重要示踪元素。本文试图从Ni、Cu和PGE地球化学性质和行为入手,并借助一些研究实例,对它们在幔源岩浆起源和演化以及岩浆硫化物矿床成因研究中的示踪意义进行系统介绍。     

广东省就业空间的性别化及权力特征

采用2000年第五次人口普查的数据,以市辖区(县、市)为基本地理单元,对广东省的21个地级市133个样本进行性别与就业空间的实证研究。通过分别对男性和女性6类就业区的比较分析发现,①广东省不同性别的就业整体同构与一定程度的性别隔离并存。整体同构来自互补性的就业角色,两性关系是平等的;性别隔离来自于隔离性的就业角色,两性之间存在着控制与被控制的权力关系。女性就业在与男性总体平等的同时,也存在被边缘化的现象。②在经济全球化和世界制造业转移的大背景下,不同性别的就业空间形成了中心-边缘结构。高度集聚的就业活动分布在环珠江口的珠江三角洲的经济中心区,与珠三角以外的其他就业区在空间上形成了核心-边缘结构。③不同性别的就业空间具有权力特征,具有生产性。中心-边缘结构构建了一种以广州和深圳为极点的就业空间秩序,这种结构制约着区域就业空间新秩序的出现,也体现为区域就业秩序下一种社会经济关系的生成。④在地域文化的深刻影响下,除粤东部分传统地区之外,广东不同性别的就业差异并未构成整体的就业空间性别化。     

Segregated ice structures in various heaved permafrost landforms through CT Scan

The growth of segregated ice lenses in frost susceptible sediments in the discontinuous permafrost zone is the dominant mechanism for the formation of permafrost mounds, such as palsas, lithalsas and permafrost plateaus. Thawing of these mounds creates thermokarst lakes, which are particularly abundant in Nunavik, east of the Hudson Bay area. The inception of the permafrost in mounds and their growth are regulated by climate conditions, by local Quaternary geology and by environmental factors such as topography, vegetation, snow cover and surface humidity. Variable sizes and morphology of the permafrost mounds can be attributed to local factors that affect the ice segregation process, particularly the supply of water needed for ice‐lens growth and grain‐size composition of the soil into which aggradation takes place. Computer image analysis of CT scans on high quality cores obtained from permafrost mounds and plateaus of various shapes reveal that the ice layer sequences and permafrost internal structure vary with landform types. A relationship therefore exists between different morphological type within a family of landforms and their microscale internal structure. Copyright © 2007 John Wiley & Sons, Ltd.     

Circulation of bubbly magma and gas segregation within tunnels of the potential Yucca Mountain repository

Following an intersection of rising magma with drifts of the potential Yucca Mountain nuclear waste repository, a pathway is likely to be established to the surface with magma flowing for days to weeks and affecting the performance of engineered structures located along or near the flow path. In particular, convective circulation could occur within magma-filled drifts due to the exsolution and segregation of magmatic gas. We investigate gas segregation in a magma-filled drift intersected by a vertical dyke by means of analogue experiments, focusing on the conditions of sustained magma flow. Degassing is simulated by electrolysis, producing micrometric bubbles in viscous mixtures of water and golden syrup, or by aerating golden syrup, producing polydisperse bubbly mixtures with 40% of gas by volume. The presence of exsolved bubbles induces a buoyancy-driven exchange flow between the dyke and the drift that leads to gas segregation. Bubbles segregate from the magma by rising and accumulating as a foam at the top of the drift, coupled with the accumulation of denser degassed magma at the base of the drift. Steady-state influx of bubbly magma from the dyke into the drift is balanced by outward flux of lighter foam and denser degassed magma. The length and time scales of this gas segregation are controlled by the rise of bubbles in the horizontal drift. Steady-state gas segregation would be accomplished within hours to hundreds of years depending on the viscosity of the degassed magma and the average size of exsolved gas bubbles, and the resulting foam would only be a few cm thick. The exchange flux of bubbly magma between the dyke and the drift that is induced by gas segregation ranges from 1 m³ s⁻¹, for the less viscous magmas, to 10⁻⁸ m³ s⁻¹, for the most viscous degassed magmas, with associated velocities ranging from 10⁻¹ to 10⁻⁹ m s⁻¹ for the same viscosity range. This model of gas segregation also predicts that the relative proportion of erupted degassed magma, that could potentially carry and entrain nuclear waste material towards the surface, would depend on the value of the dyke magma supply rate relative to the value of the gas segregation flux, with violent eruption of gassy as well as degassed magmas at relatively high magma supply rates, and eruption of mainly degassed magma by milder episodic Strombolian explosions at relatively lower supply rates.     

Characteristics of post-socialist urban transformation in East Central Europe

The development of the post-socialist city has already been characterised by substantial restructuring processes. Particular emphasis should be drawn to the take-off of the tertiary sector and the comprehensive blight phenomena in the previously industrial areas. The urban housing sector has witnessed increasing housing affordability problems, a marginalisation of communal housing stock, an increase of segregation and an intensification of the decay in the old housing stock. In all East Central European states the spatial development processes of industry and services within the cities basically show clear parallels to the pattern of urban development in continental Europe. In Hungary housing policy, tenure structure and the level of segregation already show relatively closer similarities to the neoliberal, Anglo–American pattern of development. The other ECE states show closer similarities to the corporatist welfare states of continental Europe. As far as medium-term urban development in East Central Europe is concerned, it is to be assumed that – regardless of the specific path of further development – overall solutions shall not be found for the fundamental problems which are the legacy of the socialist era – the decay of old housing stock, large scale derelict industrial areas and the extent and deficiencies of high-rise housing estates. This revised version was published online in July 2006 with corrections to the Cover Date.     

皱纹盘鲍杂交F1AFLP标记偏分离现象初析

运用AFLP标记技术对皱纹盘鲍(Haliotis discus hannaiIno)及杂交F1代共86个个体进行分析,检测了32对AFLP引物组合,共产生2688个AFLP片段,平均每个引物组合产生84个片段。在子代中分离的片段有483个,包括母本标记230个,父本标记135个,双亲本共有的标记118个。卡方检验表明167个母本和100个父本标记符合1∶1的孟德尔分离比例,78个标记符合3∶1的分离比例,其偏分离比例分别达到27.4%,25.9%和33.9%。本研究发现无论是雌性还是雄性偏分离标记都主要是纯合子过剩,初步推测造成偏分离的原因可能与两个鲍鱼群体的某些基因不兼容有关。     

粘土矿物含量分析中的几个问题

储层岩石中粘土矿物种类及含量分析是划分沉积相带和成岩相带的基础,也是油气层钻井、完井、开发改造中储层保护的关键。本文在分析传统粘土矿物抽提分离方法及其缺点的基础上,提出了多级粒度抽提分离方法,为分析储层岩石中的粘土矿物种类和含量提供了首要的保障。     

新疆东天山黄山东岩体橄榄石成因意义探讨

黄山东岩体位于新疆东天山造山带中段,由四次岩浆侵入形成:第一次侵入形成了岩体上部的橄榄辉长岩、角闪辉长岩和闪长岩,构成岩体的主体;第二次侵入形成辉长苏长岩,呈岩墙状分布于岩体西端和西北部;第三次侵入岩石为斜长二辉橄榄岩,位于岩体下部,为主要的赋矿岩石;第四次侵入岩石为底部角闪辉长岩。橄榄石为第三次侵入的斜长二辉橄榄岩和第一次侵入的橄榄辉长岩主要造岩矿物之一,橄榄石的镁橄榄石牌号(Fo)值介于68.5～82.5之间。其中含硫化物斜长二辉橄榄岩中的橄榄石具有较高的Fo值(79.7～82.5);斜长二辉橄榄岩中橄榄石的Fo值为78.3～79.9;而基性程度较低的橄榄辉长岩中橄榄石具有较低的Fo值(68.5～72.2)。利用橄榄石矿物成分计算得出黄山东岩体母岩浆Mg#(Mg2+/(Mg2++Fe2+))为0.59,为原生玄武质岩浆经历结晶分异作用形成。模拟计算结果显示黄山东岩体不含矿岩石中橄榄石是母岩浆经过2%的橄榄石结晶分异且硫达到饱和后,在硫化物熔离的同时岩浆发生橄榄石结晶而形成,并且橄榄石︰硫化物≈50︰1,部分橄榄石成分投点在橄榄石结晶和硫化物熔离的模拟曲线右下侧,指示它们可能受到晶间硅酸盐熔浆作用的影响。含硫化物斜长二辉橄榄岩中Fo值与Ni含量呈负相关关系,说明橄榄石与硫化物熔体之间发生了Fe-Ni交换反应。     

BOOK REVIEWS

Book Reviewed in this article: Geography and the Third World. International Seminar, 14–18 May 1980, Kuala Lumpur, Malaysia . Ishmail Ahmad and Jamaluddin Md Jahi, eds. The Growth Dilemma: Residents' Views and Local Population Change in the United States . Mark Baldassare. Sport and Place: A Geography of Sport in England, Scotland & Wales . John Bale. The Deindustrialization of America: Plant Closings, Community Abandonment, and the Dismantling of Basic Industry . Barry Bluestone and Bennett Harrison. Selected Essays 1963–1975: Carl O. Sauer . Bob Callahen, ed. Housing and Planning in the Countryside . G. Clark. Conflict, Politics and the Urban Scene . Kevin R. Cox and R. J. Johnston, eds. Thematic Maps: Their Design and Production . David J. Cuff and Mark T. Mattson. Wine: A Geographic Appreciation . Harm Jan de Blij. USSR in Maps . J. C. Dewdney. Political Geography: A Contemporary Perspective . Ramesh D. Dikshit. Rethinking Human Adaptation . Rada Dyson-Hudson and Michael A. Little, eds. Sacred Sands: The Struggle for Community in the indiana Dunes . J. Ronald Engel. Geography of the Biosphere . A. Furley and Walter W. Newey. Disaster and Reconstruction . Robert Geipel. Glasgow: The Making of a City . Andrew Gibb. Design for Arid Regions . Giden S. Golany, ed. Urbanization and Cancer Mortality: The United States Experience, 1950–1975 . Michael R. Greenberg. Geology in the Nineteenth Century: Changing Views of a Changing World . Mott T. Greene. Colonización y Destrucción de Bosques en Panamá . Stanley Heckadon Moreno and Alberto McKay, eds. Urban Geography: A First Approach . David T. Herbert and Colin J. Thomas. The Visual and Spatial Structure of Landscapes . Tadahiko Higuchi. Climate from Tree Rings . M. K. Hughes, P. M. Kelly, J. R. Pilcher, and V. C. LaMarche, Jr., eds. The structure of Nineteenth Century Cities . James H. Johnson and Colin G. Pooley, eds. The American Planner: Biographies and Recollections . Donald A. Krueckeberg, ed. Urban Land Policy For the 1980s, the Message for State and Local Government . George Lefcoe, ed. Regional Planning: Evolution, Crisis and Prospects . Gill C. Lim, ed. Relevance and Ethics In Geography . Bruce Mitchell and Dianne Draper. China: The Geography of Development and Modernization . Clifton W. Pannell and Laurence J. C. MA. The Urban Retailing System . Robert B. Potter. Hants. Nonconventional Energy Resources . Philip R. Pryde. Caribbean Migrants: Environment and Human Survival on St. Kitts and Nevis . Bonham C. Richardson. Population and Resources . Harry Robinson. East Los Angeles: History of A Barrio . Ricardo Romo. Integrated Impact Assessment . Frederick A. Rossini and Alan L. Porter, eds. Environmental Aesthetics: Essays in Interpretation . Barry Sadler and Allen Carlson, eds. Earthwatch . Charles Sheffield. Field Techniques and Research Methods in Geography . Robert H. Stoddard. Haiti: Land of Poverty . Robert J. Tata. Weathering and Erosion: Sources and Methods in Geography . Stephen T. Trudgill. Once Beneath the Forest. Prehistoric Terracing in the Río Bec Region of the Maya Lowlands . B. L. Turner, II. The Historical Geography of Scotland since 1707 . David Turnock.     

Socio-spatial segregation in China and migrants’ everyday life experiences: the case of Wenzhou

Although internal migration is one of the most frequently discussed aspects of China’s twenty-first century urbanization, much of the research in this area emphasizes megacities. This paper, however, focuses on Wenzhou, a Chinese city that served as a national model for the introduction of small-scale private enterprise in the 1990s. Through a survey of migrants living in the subdistrict of Shuangyu, a settlement dominated by manufacturing workers, this article argues that socio-spatial segregation research should pay more holistic attention to migrants’ use of urban space, beyond simply place of residence. Focusing on how migrants use space in several aspects of their everyday lives, this article contends that Shuangyu is socially and spatially segregated from other parts of the city. Rather than neatly incorporated into the rest of the city, migrant settlement in Wenzhou is both marginalized and independent. We thus theorize Shuangyu’s place in Wenzhou’s new socio-spatial structure as a “city within the city.”