Export of Acidity in Drainage Water from Acid Sulphate Soils

Disturbed acid sulphate soils are potent sources of acidity in coastal waterways. Monitoring studies of the drainage water for sites at East Trinity, Cairns and Pimpama, south-east Queensland indicate that considerable acidity is found in the drainage water from these sites. Hydrogen (H⁺), ferrous (Fe²⁺) and aluminium (Al) ions are the dominant acid cations involved. When drainage water is mixed with fresh or marine waters the effect of H⁺ on acidity generation is immediate. Aluminium can release acidity on hydrolysis, while the oxidation of Fe²⁺ to Fe³⁺ both acidifies and removes dissolved oxygen from the water. Strongly acidic waters with low levels of dissolved oxygen concentration are undesirable for most forms of aquatic life. Export of acidity from acid sulphate soil is likely to have a major effect on inshore fisheries and breeding grounds especially in periods of flood following drought or periods of low rainfall, where large volumes of acidity can be flushed/leached into sensitive aquatic/marine habitats. Impacts may include low dissolved oxygen, fish kills, epizootic ulceration syndrome and damage to oysters. During the processes of oxidation and hydrolysis, iron and aluminium flocs form, that can smother benthic communities. Heavy metals are found in the drainage water at elevated levels and may also be of concern for aquatic organisms. Chronic effects such as habitat degradation, mortality of marine worms, bivalves, invasion of acid tolerant species (both plant and animal) and avoidance of habitat have been documented elsewhere. These areas require further research.     

湖南沃溪金锑钨矿床的金矿化作用研究:基于元素地球化学特征和自然金的热力学模拟分析

湖南沃溪金锑钨矿床是江南造山带中金、锑、钨、均达到大型规模的典型矿床,其自然金的金成色值极高(＞998)。本文聚焦湖南沃溪金锑钨矿床中金矿化作用,通过ICP- MS测试和包裹体显微测温实验查明不同矿物与围岩的元素地球化学特征和成矿流体特征,并通过热力学模拟分析自然金的成矿条件,探讨金成色值及金银比值对金矿化的指示作用和研究价值。ICP- MS测试结果显示,金银比值在白钨矿(103~520)和黄铁矿(69~673)中相对较高,在辉锑矿(6~65)和围岩(0. 3~35)中相对较低,在石英(6~199)中则变化较大。基于包裹体显微测温结果(200~350℃),本文建立了自然金成矿流体的热力学模型,分析并查明在黄铁矿与绢云母共生的自然金成矿流体中,硫离子浓度比温度更容易影响金溶解度,且金成色值主要与温度呈正相关,与硫离子浓度呈负相关。通过对比研究和讨论,认为沃溪矿床大量金矿化可能形成于温度较高和硫离子浓度较低的白钨矿成矿流体中,而极高成色值的自然金可能与高金银比值的白钨矿和黄铁矿共生。上述方法和结论可为其他金矿床的研究提供新思路。     

基韦诺半岛与滇黔地区玄武岩铜矿对比研究

滇黔地区玄武岩铜矿有很长的找矿与开发历史,但矿床规模较小。有研究者认为其与美国基韦诺铜矿极具相似性,并认为加强区内地球化学边界及铜矿床研究,将对成矿理论发展及经济价值方面具有重要意义,此举引发了新一轮的研究与找矿热潮,但收效甚微。为探索滇黔地区找矿过程中所遇之困惑以及更进一步探明资源潜力,本文在详细了解基韦诺半岛铜矿特征基础上,展开了其与滇黔地区铜矿的相似性、差异性对比研究。认识到以往对基韦诺半岛铜矿特征描述存在偏差,基韦诺半岛铜矿与滇黔地区铜矿之间相似性与差异性共存,滇黔地区红层化作用不足可能影响了成矿规模,但可寻找地质环境有利矿种;提出玄武岩自然铜矿化可能潜力有限,三叠系砂岩型铜矿需要继续关注以及其他铜矿类型具有找矿价值较小或尚需研究的建议。     

Distribution patterns of the invasive herbivore Siganus luridus (Rüppell, 1829) and its relation to native benthic communities in the central Aegean Sea,Northeastern Mediterranean

The present study explores the distribution of the invasive herbivore fish Siganus luridus (Rüppell 1829) and its relationship to native herbivores and macroalgal assemblages in the shallow sublittoral of the Cyclades Archipelago, Aegean Sea, Greece. In situ underwater surveys of herbivore abundance (fishes and sea urchins) and algal coverage were carried out at 180 sampling sites in 18 islands. Siganus luridus accounted for 17% of the total herbivore abundance, with a decrease in relative abundance from the southeastern to the northwestern islands. In Santorini Island (in the southeast of the study area) S. luridus abundance accounted for 90% of the total herbivore fish abundance, while in Kea Island (at the northwestern limit of the study area), S. luridus was absent. The spatial variation of minimum sea surface temperature is possibly the reason for its distributional pattern. Siganus luridus abundance was found to be positively correlated to the native herbivore Sparisoma cretense (Linnaeus 1758). A significant negative relationship was found between the abundance of the invasive species and the sum of erect and canopy algae cover (Dictyotales and Cystoseira spp.), which are the main components of its diet in the region. On the other hand, its occurrence was particularly high in barren sites. The results arising from this study reinforce evidence from studies in the Eastern Mediterranean Basin that the expansion of the invasive species S. luridus may have profound impacts on native communities in the Mediterranean infralittoral zone.     

基于eXist的GML数据管理

由于GML所采用的层次模型与关系模型之间存在重大差异,传统的关系模型不适合半结构化的GML数据的存储.针对该问题,本文从本原XML数据库(NXD)的角度,对GML空间数据存储问题进行了研究.首先分析了NXD的特征及其相对于XED的优势,然后对当前主流NXD的优缺点进行分析与比较,结合GML的特点,选用eXist对GML...     

四川盆地富硫天然气与盆地周缘铅锌铜矿的成因联系

金属元素的搬运和沉淀是热液矿床成矿机理研究的重要方面。目前人们普遍认为热液矿床中金属元素主要呈硫的络合物和卤素络合物形式搬运。MVT铅锌矿床等硫化物矿床盐度较高,包裹体成分中阳离子以Na+、K+、Ca2+、Mg2+为主,阴离子以Cl-、F-、CO2-3为主,很少有HS-、S2-,表明金属元素主要以氯的络合物形式搬运,外来硫的加入是导致铅锌成矿物质以硫化物形式沉淀成矿的关键。四川盆地天然气中富含H2S,其与周缘MVT铅锌矿床具有密切的时空关系,据此推测天然气中的H2S可能是导致铅锌硫化物沉淀形成MVT铅锌矿床的主要硫源,天然气中的H2S与铅锌成矿流体在古油藏中作用形成含沥青的铅锌矿床;当含硫化氢的天然气运移离开古油藏后与含矿流体混合时,形成不含沥青的铅锌矿床。另外,石油热裂解产生的不含H2S的天然气使得含铜热液中的铜还原,以自然铜形式沉淀形成含沥青的玄武岩铜矿;石油热化学硫酸盐还原(TSR)过程中,还会发生溶蚀作用,扩大碳酸盐岩孔隙,为成矿提供空间。     

Epigenetic hydrothermal origin of native copper and supergene enrichment in the Vista Alegre district,Paraná basaltic province,southernmost Brazil

Native copper is widespread in the Lower Cretaceous Paraná basaltic province, southern Brazil, both as films in fractures and as massive balls in amygdules. The focus of this investigation is on the large concentration of occurrences (n = 85) that forms the Vista Alegre district in the border region of Rio Grande do Sul and Santa Catarina states. The high average of 220 ppm Cu content of the basalts resulted in ore of native copper, Cu oxides, abundant chrysocolla in the top of mineralizations, and minor malachite and azurite. Native copper is associated with dioctahedral and trioctahedral smectites, zeolites (heulandite and clinoptilonite), quartz, and calcite, typical of a low-T (100–150°C) hydrothermal alteration assembly. The PGE distribution shows enrichment in Pd in relation to Pt both in basalts and in native copper, supporting the hypothesis of hydrothermal origin of the mineralization. No evidence was found of direct precipitation of copper from the lava; based on field and petrographic evidence, integrated with BSE images, EPMA analyses, EGP contents of native copper, and bulk rock analyses, this is an epigenetic hydrothermal copper mineralization, followed by supergene enrichment.     

云南省蝉战河自然铜矿床类型及找矿方向研究

扬子地块西南缘是我国重要铜成矿带之一,该区已发现多个典型的火山-沉积碎屑岩型和陆相砂页岩型铜矿.蝉战河铜矿床具有典型的两种矿床类型特征.在系统总结该矿床地质特征的基础上,分析了两种矿床类型的各自特征,初步认为区内具中—大型铜矿成矿条件,并提出了找矿方向.     

干旱区不同土壤和作物灌溉量的无机碳淋溶特征实验研究

为探讨干旱区作物灌溉对盐碱土无机碳传输的影响,通过选择不同含盐量的土壤,即耕地土（F）、混合土（C）和原生荒漠土（D）,分别种植水稻（R）和棉花（C）,进行了一个生长季的淋溶实验,并定期收取且分析土壤淋溶液中的可溶性无机碳（DIC）含量。结果表明：（1）水稻处理无机碳的淋溶主要集中在秧苗分蘖期和幼穗发育期,而棉花处理则集中在花铃期和吐絮期;（2）不同含盐量土壤在同一灌溉量下,土壤含盐量越高,其淋溶过程得到的无机碳总量越大,最高约为8.4 g·m^-2·a^-1,最低仅约0.7 g·m^-2·a^-1;（3）同种土壤不同灌溉量,其水稻高于棉花,高出值范围为2.9～4.1 g·m^-2·a^-1;种植作物处理得到的无机碳总量均大于其相应对照处理的量（p＜0.05）。研究结果表明,土壤的盐含量及作物灌溉量对土壤无机碳淋溶有重要影响。     

政府与村民的行为对古村落保护及景观变迁的影响——基于本土社会学理论视角

为探究中国古村落景观变迁的发生机理及不同行动者在此过程中的行为逻辑,对浙江省永嘉县境内的楠溪江古村落群进行了案例研究。从本土社会学的理论视角,指出:中国的乡土社会是一个情理社会,国家正式权力镶嵌于乡土文化之中,正式权力与非正式权力、政府与村民的互动推动了古村落景观的变迁。借用"国家-社会"二元框架,将变迁中的行动者分为县(市)政府,乡镇政府,有关系村民和无关系村民四类,指出不同的行动者具有各不相同又彼此联系的行为逻辑,为常态下的中国古村落景观变迁提供了一种行动者类型框架和一种理解方式。