Native aluminium (spherules and particles) in the Central Indian Basin sediments: Implications on the occurrence of hydrothermal events

We have sampled particles of native aluminium (Al°) in two sediment cores from the Central Indian Basin (CIB). The cores are geographically separated but are located at the base of two seamounts. The native Al° particles occurring as grains and spherules, have an average Al content of  95% and are associated with volcanogenic–hydrothermal material. Morphologically and compositionally, the specimens are similar to those reported from the East Pacific Rise. After ruling out several processes for the presence of the native Al°, we hypothesize that during progressive melting of magma, a basaltic magma is produced which has high contents of reductants such as methane and hydrogen, and a low oxygen fugacity. During the upward migration of such magma, reduction to metallic aluminium and the formation of native Al° particles takes place.     

实验变差函数计算方法的研究与运用

本文系统、详尽地分析讨论了不同样品数据条件下实验变差函数的计算方法。在实验变差函数计算流程的设计和有效样品搜索域的确定方面提出了自己独特的见解。最后用一个矿山的控矿工程教据对文中介绍的方法进行了测试。结果表明,利用本文的方法,容易得到稳健、准确、信息量高的实验变差函数。     

Cross-scale analysis of cluster correspondence using different operational neighborhoods

Cluster correspondence analysis examines the spatial autocorrelation of multi-location events at the local scale. This paper argues that patterns of cluster correspondence are highly sensitive to the definition of operational neighborhoods that form the spatial units of analysis. A subset of multi-location events is examined for cluster correspondence if they are associated with the same operational neighborhood. This paper discusses the construction of operational neighborhoods for cluster correspondence analysis based on the spatial properties of the underlying zoning system and the scales at which the zones are aggregated into neighborhoods. Impacts of this construction on the degree of cluster correspondence are also analyzed. Empirical analyses of cluster correspondence between paired vehicle theft and recovery locations are conducted on different zoning methods and across a series of geographic scales and the dynamics of cluster correspondence patterns are discussed.      

四川石棉县首次发现独特的自然铂矿床

攀西地区大片前震旦纪结晶基底杂岩中产出有众多的前晋宁期层状侵入体，其间可见钒钛磁铁矿化，铬铁矿化，最近在石棉境内新发现一处含铂矿化体呈层状，网脉状产于层状侵入体中，且多以自然铂单矿物存在。伴生主要矿物为磁铁矿，钛铁矿，黄铁矿，黄铜矿等。初步认为该矿床类型属产于层状铁质基性-超基性岩与铜硫化物-钡钛磁铁矿有关的构造-热液再活化型自然铂矿床。     

Yixunite and Damiaoite—A Twin of New Native Alloys of Indium and Platinum from the Yanshan Mountains

Yixunite and damiaoite Were found in a cobalt- and copper-bearing platinum ore vein of a contact metasomatic deposit. The chief ore minerals are bornite, chalcopyrite, magnetite and carrollite. The platinum minerals include moncheite, sperrylite, daomanite, cobalt malanite and cooperite. Yixunite and damiaoite occur as immiscible globules, 1.0 to 2.0 mm in diameter. Yixunite is always in the central part of a globule. It is opaque with metallic lustre, bright white colour and black streak. HM = 5.8; VHN50 = 634 kg/mm2 (573-681 kg/ mm2); insoluble in HCl, HNO3, HF or H3PO4; no cleavage; no magnetism. Density is hard to measure because of small grain size. Calculated density = 18.21 g/cm3. Reflective colour is bright white with a yellowish tint. Isotropic. The mean analytical results (ranges) (%) are: Pt 82.8 (81.8-83.6), In 16.4(15.6-17.1) and total 99.2. The empirical formula (based on 4 atoms) is Pt2.993 In1.007 . The five strongest lines of X-ray diffraction (hkl, d,I) are 111, 2.30 (100); 200, 1.99 (     

Local provenance in rehabilitation of degraded landscapes: a case study from the Hawkesbury–Nepean catchment, Australia

Throughout Australia thousands of volunteers are engaged in Landcare projects that should help rehabilitate degraded landscapes. Many of these projects involve tree planting, but their seed is not necessarily of local provenance. Based on a survey of 85 Landcare groups working in the Hawkesbury–Nepean catchment, data were collected about Landcare groups' knowledge of their seed source, understanding of local provenance and the ecosystem in which they were planting trees and the source of funding for their projects. The findings from the study indicate that about one in five (21%) of the groups surveyed that introduced plant material were not aware of local provenance issues. Indirect indications were that a large number of Landcare groups state-wide may be doing more harm than good to the landscape while trying to rehabilitate it. The data also showed that one in seven (13%) of the groups funded by the Australian Government through the Natural Heritage Trust (NHT) had limited awareness of local provenance issues. With millions of dollars being spent on 'works on the ground', it would be prudent to allocate some funds to document and monitor current Landcare activities, so that the environmental outcomes can be quantified and more effective Landcare policies can be developed in the future.     

The Globalization of a Panethnopolis: Richmond District as the New Chinatown in San Francisco

This paper briefly reviews the sociological literature on the “New” Chinatown phenomenon stressing its structural location vis-à-vis the “Old” Chinatown and the homeland. It defines the New Chinatown as a panethnopolis, that is a global neighborhood with a majority population of Chinese immigrants and of other ethnic groups of mostly Asian descent. It analyzes more particularly the formation, development, and integration of San Francisco’s Richmond District’s New Chinatown into both the city where it is located and the network of transglobal sites to which it belongs. It provides an interpretation of the New Chinatown as a cultural enclave within the context of globalization theory.     

顾及邻域居民地群组相似性的道路网匹配方法

现有多源同比例尺道路网匹配方法中,大多只利用道路自身特征进行匹配,而较少顾及道路周边要素对匹配过程的影响和约束,从而影响了道路网匹配效果的进一步提高,特别是对系统误差改正后仍存在一定位置或旋转偏差的道路数据进行匹配时,这种影响尤为明显。本文借鉴人类对陌生环境的空间认知特点,提出了一种顾及邻域居民地群组相似性的道路网匹配方法。该方法通过构建城市骨架线网确定与道路相邻的居民地群组,进而计算居民地群组空间关系和几何特征相似度来获得对应道路的匹配结果。其特点在于:对存在位置或旋转偏差的道路数据匹配,以其邻域空间内居民地群组的整体相似性指标来带动道路自身匹配,实际上是增加了周边居民地群组对道路匹配过程的约束,更具鲁棒性。试验及对比分析表明,本方法能够较好地解决系统误差改正后仍存在较大位置和旋转偏差的道路数据间的匹配问题,提高匹配的正确率。     

河南嵩县松里沟金矿床中碲化物的发现及其地质意义

松里沟金矿位于华北陆块南缘熊耳山地区,已探明金资源储量26 t。矿体产于中新太古界-古元古界太华群片麻岩NWW向的断裂带中。其热液成矿过程包括4个成矿阶段:黄铁矿-石英阶段、石英-黄铁矿阶段、金-碲化物阶段和石英-碳酸盐阶段。显微镜下发现金-碲化物阶段存在大量与金共生的碲化物。利用电子探针和能谱分析查明碲化物的种类、共生关系和形成条件,确认的碲化物有碲铅铋矿、碲铅矿、碲铋矿、碲金矿、碲金银矿、硫碲铋铅金矿、辉碲铋矿,此外还有大量的自然金和少量的辉铋矿。该矿床为一与岩浆作用有关的碲金矿床。Au主要以自然金和金银碲化物的形式存在。Au、Ag以硫氢络合物的形式发生迁移,Te2(g)和H2Te(g)冷凝进入含贵金属的氯化物溶液是碲化物沉淀主要机制。相图及化学反应方程式分析表明,金-碲化物阶段受温度、碲逸度、硫逸度、氧逸度和酸碱度控制,其中,黄铁矿-石英阶段和石英-黄铁矿阶段形成于logf_(Te2)-14.4和logf_(S2)=-11.1~-6.5的环境。金-碲化物阶段形成于温度为110~313℃、logf_(Te2)=-15.2~-9.4和logf_(S2)=-16.5~-14.6、f_(O_2)升高和pH值降低的环境。碲化物的发现为探讨该矿床成因和熊耳山地区寻找同类型的矿床提供了依据。