东南大陆中生代玄武岩岩石系列及其构造意义

东南大陆中生代玄武岩和玄武安山岩占区内酸性岩浆作用的5-10％,并为钙碱系列和过渡系列。其矿物组合为斜长石+单斜辉石+角闪石±黑云母+透长石,玄武岩因LIL元素(K、Rb、Th、Ta、Ce)含量高,负Nb异常以及Fe、Mg、Cr、Ni、Co、Sc含量低而不同于产在活动大陆边缘环境的同类岩石,其LIL元素(K、Rb、Ce、Ba)与本区新生代玄武岩相似,但Fe、Mg、Cr、Ni、Co、Sc含量明显偏低。成分分带与酸性岩浆作用的分带性一致,都受壳、幔成分和构造等地质背景控制,产出构造环境为相对稳定的板内区。玄武质岩浆主要由酸性岩浆作用提供热源,地壳发生广泛熔融。从中生代至新生代,由下地壳至上地慢,由钙碱性和过渡系列至碱性系列,是扩张作用逐渐增强的结果。     

弹塑性极限平衡法分析复杂岩质边坡的稳定性

笔者采用弹塑性极限平衡法来研究分析复杂岩质边坡的稳定性 ,即以塑性极限理论为基础 ,应用逐渐降低材料强度来逼近系统的极限平衡 ,并以屈服区的贯通来表征系统的极限平衡状态。此时 ,系统达到临界平衡状态时所对应的材料强度降低倍数即为整体最小安全系数 ,临界平衡状态定义为边坡内的塑性屈服区能够形成潜在的滑移通道时的状态。以城门山露天矿南帮边坡为研究对象 ,通过自行改编的NCAP -FS程序进行了数值分析 ,结果表明 ,南帮边坡现阶段是安全稳定的 ,与现场观测结果一致。     

岩体声发射技术在金川二矿区的应用

岩体声发射技术是利用岩体变形破坏过程中产生应力波的强弱,来监测岩体的安全状态。针对金川二矿区地压大、岩体破碎的特点,金川公司先后在二矿区１１５０ｍ水平二期快进巷道、８０１采场、１４３８ｍ水平１２＃采场进路等处进行了应用岩体声发射预报矿岩体和充填体安全状态的试验。在对试验过程和监测结果进行分析的基础上,初步建立了金川二矿区矿岩体和充填体安全状态与声发射参数的近似关系,为实现金川二矿区安全管理的定量化进行了有益探索。     

轮南地区奥陶系天然裂缝的发育机理及其对流体活动的控制

地下天然裂缝是导致地质灾害的主要原因之一 ,其机理研究是防灾的基础。轮南地区奥陶系天然裂缝的埋深在 5 0 0 0m以下 ,其发育受多种因素控制 ,且在地质演化过程中经历了多期发育而成 ,发育机理非常典型、复杂。笔者通过观察、描述岩心的裂缝发育特征 ,分析了深度、温度、围压等的变化以及剥蚀、裂缝充填对地下岩体力学性质的影响 ;进而建立综合数学模型 ,对裂缝发育概率分布和发育特点做出预测 ;根据计算结果 ,分析了轮南地区奥陶系天然裂缝的发育机理 ;通过天然裂缝分布与井内流体测试结果的对比分析 ,探讨了裂缝分布对地下流体活动的控制作用。     

煤层注水预防冲击地压的研究

煤层注水防治冲击地压的方法简易、价廉、适应性广 ,同时具有降尘、降温及软化煤层功用 ,一举数得 ,可以作为冲击地压防治的首选措施。煤层注水防治冲击地压的机理以及注水过程中 ,对水在煤层中的运动规律还缺乏研究 ,因而工艺参数决定只能依靠经验 ,存在很大盲目性 ,必然影响防治效果。因此 ,笔者从水对煤物理力学性质的影响 ,对煤层注水防治冲击地压的机理等方面进行了分析和研究 ,认为煤层注水过程 ,实际上是水驱气的驱替过程 ,是有动界面的渗流力学问题 ,为此 ,进一步研究了水在煤层中的运动规律。研究的结果和有关数据 ,为制订煤层注水防治冲击地压的工艺参数提供依据 ,为有效地防治冲击地压的发生 ,提供了新的手段。     

Microbial Biomass,P-Nutrition,and Enzymatic Activities of Wheat Soil in Response to Phosphorus Enriched Organic and Inorganic Manures

Compost was prepared from wheat straw enriched with Rajasthan rock phosphate and Aspergillus awamori. The resulting phospho-compost along with phosphorus enriched FYM, mineral fertilizer (rock phosphate) and super phosphate were evaluated for their individual contribution in improving organic matter status, P availability, and enzymatic activities of soil under wheat crop grown in a micro plot. The results showed that total organic carbon, nitrogen, microbial biomass, and humus content (an index of organic matter status of soil) of soil was highest when farmyard manure (FYM) after its enrichment with 12.5% rock phosphate was applied. Microbial enriched phospho-compost was the product yielding highest soil available phosphorus, phosphorus uptake, urease, and cellulase activities. However, FYM amended with 25% rock phosphate resulted in the greatest enhancement of β-glucosidase. Measured parameters indicated a sure improvement of chemical and biological activities of soil after the application of phosphorus enriched organic amendments compared to the commercial fertilizer commonly used by the Indian farmers.     

Climate Change and Water Resources in Arid Mountains: An Example from the Bolivian Andes

Climate change is projected to have a strongly negative effect on water supplies in the arid mountains of South America, significantly impacting millions of people. As one of the poorest countries in the region, Bolivia is particularly vulnerable to such changes due to its limited capacity to adapt. Water security is threatened further by glacial recession with Bolivian glaciers losing nearly half their ice mass over the past 50 years raising serious water management concerns. This review examines current trends in water availability and glacier melt in the Bolivian Andes, assesses the driving factors of reduced water availability and identifies key gaps in our knowledge of the Andean cryosphere. The lack of research regarding permafrost water sources in the Bolivian Andes is addressed, with focus on the potential contribution to mountain water supplies provided by rock glaciers.     

Sediment quality guidelines for copper and zinc for filter-feeding estuarine oysters?

Sediment quality guidelines (SQGs) assess the ability of bottom sediment to sustain healthy infauna and water quality guidelines (WQGs) provide protection for a designated percentage of aquatic species. Filter-feeding marine species, e.g. oysters and mussels, acquire food from particles in the water column and protection of these animals is not provided by SQGs or WQGs. The current work investigated the relationship between metal (Cu, Zn) concentrations in total and fine-fraction (<62.5 μm) surficial sediment digested in a range of acids and chelating agents and oyster tissue metal concentrations. A strong correlation between oyster tissue Cu and Zn concentrations and fine-fraction surficial sediment digested in 1 M HCl provided a sedimentary guideline which predicted tissue metal concentrations in oysters and established a level (<45 μg g⁻¹ and <1000 μg g⁻¹, respectively) for protecting oysters from exceeding human consumption levels (70 μg g⁻¹ and 1000 μg g⁻¹, respectively).     

Relative importance of male and territory quality in pairing success of male rock ptarmigan (Lagopus mutus)

We studied pairing success in male rock ptarmigan (Lagopus mutus) in northern Alaska to learn whether males obtaining more females possessed phenotypic traits that influenced female choice directly, whether these traits permitted males to obtain territories favored by females, or whether both processes occurred. The number of females per male varied from zero to three. Several male and territory traits were significantly correlated with number of females per male. We used multiple regression to obtain a single measure of male quality and a single measure of territory quality. These measures of male and territory quality correlated with each other and with male pairing success. We used path analysis to separate direct effects of male quality on pairing success from indirect effects due to high-quality males obtaining high-quality territories. Both direct and indirect pathways had significant effects on pairing success, and direct and indirect effects of male traits on pairing success were about equal. This study illustrates an analytical approach for estimating the relative importance of direct and indirect causal relationships in natural systems. Received: 13 January 1998 / Accepted after revision: 7 November 1998     

Concomitant rock phosphate dissolution and lead immobilization by phosphate solubilizing bacteria (Enterobacter sp.)

This paper examines the potential value of phosphate solubilizing bacteria (Enterobacter cloacae) in the dissolution of rock phosphate (RP) and subsequent immobilization of lead (Pb) in both bacterial growth medium and soils. Enterobacter sp. showed resistance to Pb and the bacterium solubilized 17.5% of RP in the growth medium. Enterobacter sp. did not enhance Pb immobilization in solution because of acidification of bacterial medium, thereby inhibiting the formation of P-induced Pb precipitation. However, in the case of soil, Enterobacter sp. increased Pb immobilization by 6.98, 25.6 and 32.0% with the RP level of 200, 800 and 1600 mg P/kg, respectively. The immobilization of Pb in Pb-spiked soils was attributed to pyromorphite formation as indicated by XRD analysis. Inoculation of phosphate solubilizing bacteria with RP in soil can be used as an alternative technique to soluble P compounds which can cause eutrophication of surface water.