云南金顶超大型铅锌矿区尾矿中Cd的形态分析

镉是人体非必须的有毒微量元素,Cd的不同化学形态,其生物有效性不同。通过改进的BCR分步提取法及ICP-MS分析研究发现:云南金顶铅锌矿矿区尾矿砂中Cd的主要形态为残渣态,其含量远远高于可氧化态、可还原态和弱酸提取态;金顶铅锌矿区老尾矿库中表层尾矿样品中弱酸提取态和可还原态Cd均高于底层尾矿样品,相比之下,表层尾矿中Cd等重金属元素易于释放到环境中,其生物有效性也强于底层尾矿,对环境的潜在危害大;老尾矿库尾矿砂中四种提取形态的Cd、Zn、Pb含量及金属总量均高于新尾矿库尾矿砂,这可能是由选厂工艺技术的差异造成的。     

Fluoride removal from brackish groundwater by direct contact membrane distillation

The direct contact membrane distillation applied for fluoride removal from brackish groundwater was investigated.The self-prepared polyvinylidene fluoride membrane exhibited high rejection of inorganic salt solutes.The maximum permeate flux 35.6 kg/(m2 ·hr) was obtained with the feed solution at 80°C and the cold distillate water at 20°C.The feed concentration had no significant impact on the permeate flux and the rejection in fluoride.The precipitation of CaCO3 would clog the hollow fiber inlets and foul the membrane surface with increasing concentration factor when natural groundwater was used directly as the feed,which resulted in a rapid decline in the module efficiency.This phenomenon was diminished by acidification of the feed.The experimental results showed that the permeate flux and the quality of obtained distillate kept stable before concentration factor reached 5.0 with the acidified groundwater as feed.The membrane module efficiency began to decline gradually when the feed continued to be concentrated,which can be mainly attributed to the formation of CaF2 deposits on the membrane surface.In addition,a 300 hr continuous fluoride removal experiment of acidified groundwater was carried out with concentration factor at 4.0,the permeate flux kept stable and the permeate fluoride was not detected.     

Emergence of long distance bird migrations: a new model integrating global climate changes

During modern birds history, climatic and environmental conditions have evolved on wide scales. In a continuously changing world, landbirds annual migrations emerged and developed. However, models accounting for the origins of these avian migrations were formulated with static ecogeographic perspectives. Here I reviewed Cenozoic paleoclimatic and paleontological data relative to the palearctic–paleotropical long distance (LD) migration system. This led to propose a new model for the origin of LD migrations, the ‘shifting home’ model (SHM). It is based on a dynamic perspective of climate evolution and may apply to the origins of most modern migrations. Non-migrant tropical African bird taxa were present at European latitudes during most of the Cenozoic. Their distribution limits shifted progressively toward modern tropical latitudes during periods of global cooling and increasing seasonality. In parallel, decreasing winter temperatures in the western Palearctic drove shifts of population winter ranges toward the equator. I propose that this induced the emergence of most short distance migrations, and in turn LD migrations. This model reconciliates ecologically tropical ancestry of most LD migrants with predominant winter range shifts, in accordance with requirements for heritable homing. In addition, it is more parsimonious than other non-exclusive models. Greater intrinsic plasticity of winter ranges implied by the SHM is supported by recently observed impacts of the present global warming on migrating birds. This may induce particular threats to some LD migrants. The ancestral, breeding homes of LD migrants were not ‘northern’ or ‘southern’ but shifted across high and middle latitudes while migrations emerged through winter range shifts themselves. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

江西潭坑铅锌(银)矿床特征及成因分析

江西省潭坑铅锌(银)矿区位于北武夷铅锌银成矿带内,本文系统阐述了矿区地质和矿床特征,并对矿床的成因进行了探讨。认为本区铅锌(银)矿床,经历了火山喷发沉积和后期热液充填两大成矿期,与次火山岩体(流纹斑岩)有密切的关系,属次火山热液矿床。     

河南嵩县安沟钼矿地质特征

河南嵩县安沟钼矿区构造、岩浆活动强烈,具有良好的成矿地质条件。以构造控矿为主,石英-方解石脉是钼矿的主要矿石类型,属石英-方解石脉型钼矿。本文介绍了安沟钼矿床地质特征,总结了钼矿找矿标志。     

云南东川区播卡金矿地球化学分带模式及深部隐伏矿体预测

为了探索播卡深部的找矿空间及找矿方向,本文在播卡矿区钻孔样品分析数据的基础上,研究了播卡金矿床的元素富集规律、元素组合、元素异常在地表及空间的分布特征,建立了播卡金矿的原生晕分带模型、地球化学勘查模式,提出了不同深度的原生晕判别指标,在此基础上对播卡金矿的深部隐伏矿体进行了预测。结果显示播卡金矿的深部及邻区具有寻找隐伏矿体的良好前景。     

与黑色岩系有关矿床研究进展

与黑色岩系有关矿床近年来在国内外研究中都取得了重要进展。黑色岩系不但是许多金属元素的重要来源，而且其本身也具有经济价值，但在开采利用中应注意环境保护。黑色岩系可以形成于还原环境，也可以形成于较为氧化的环境。黑色岩系中的矿床有些与生物作用有关，有些属于后生矿床，有些则与海相火山-喷气活动有关。除了本身含矿外，黑色岩系还可为其它类型金属矿床提供成矿物质或提供有利的成矿条件。     

黄旗海湖泊沉积物醋酸淋溶液的元素组成及其环境意义

黄旗海HJC剖面是氧同位素三阶段晚期(MIS3a)与现代间冰期的堆积,包括深湖相、浅湖相、冲洪积相与风成沉积。为研究各沉积相湖泊碳酸盐沉积中元素地球化学特点,对沉积物用醋酸溶液进行了选择性化学淋溶,并分析了淋溶液的元素组成。结果显示:淋溶实验较好地揭示了各沉积相的环境特点,对早、中全新世环境变化有敏感的响应;湖泊自生碳酸盐过程存在自身的元素组合特点,但在一定程度上也继承了外源组分的特点。     

核事故沾染的放射性区域所产生的地表活度分布与空中辐射场之间的换算规律--反卷积定理在核事故辐射场航测中的应用

本文应用卷积定理和反卷积定理解决了长期以来存在的任意面状放射源产生的辐射场求解问题.在核事故产生的放射性沾染区,根据本文介绍的方法,利用航空测量的某一高度平面上的照射量分布值,应用反卷积定理可求得地面上对应的放射性活度的分布,利用卷积定理可求得该活度分布所对应的任一高度平面上的照射量分布值.因该方法采用了FFT算法,故计算速度很快,可用于实时测量处理.     

福建省上杭紫金山矿田铜金银矿床类型及对比

紫金山大型铜（金）矿床是我国大陆发现的首例高硫浅成低温热液型（石英—明矾石型）矿床。随着勘探工作的深入，在该矿床深部及边部相继发现了斑岩型铜（钼）矿、中低温热液型铜金矿和低硫浅成低温热液型（绢云母—冰长石型）银、金、铜矿。各类型矿床间的浅成热液系统连续过渡，这在世界上是具代表性的矿例。不仅具有重要的找矿意义；而且在陆相火山成矿方面有重要理论意义。