Assessing the suitability of OSPAR EcoQOs for eutrophication vs ICES criteria for England and Wales

This paper provides a preliminary evaluation of the suitability of OSPAR Ecological Quality objectives for eutrophication for coastal and offshore waters of England and Wales on the basis of ICES criteria. In principle, EcoQOs are easy to understand, but responses to nutrient enrichment are complex. Few studies provide unequivocal evidence of links between inputs and response. Monitoring is generally feasible and in place, but needs to be improved. The best EcoQO is winter nutrient concentrations. Chlorophyll concentrations are a good indicator in environments susceptible to nutrient enrichment. The EcoQO for zoobenthos/fish kills potentially meets all criteria for a good indicator; EcoQOs for phytoplankton indicator species, oxygen concentrations and zoobenthos changes do not. Greater emphasis needs to be placed on seasonal effects of nutrient inputs and phytoplankton response, natural susceptibility of different water bodies, differences between coastal and offshore environments, and developing longer time series of data.     

Measurement of Charge Exchange and X-Ray Emission Cross Sections for Solar Wind-Comet Interactions

X-ray emission from a comet was observed for the first time in 1996. One of the mechanisms believed to be contributing to this surprisingly strong emission is the interaction of highly charged solar wind ions with cometary gases. Reported herein are total absolute charge-exchange and normalized line-emission (X-ray) cross sections for collisions of high-charge state (+3 to +10) C, N, O, and Ne ions with the cometary species H2O and CO2. It is found that in several cases the double charge-exchange cross sections can be large, and in the case of C3+ they are equal to those for single charge exchange. Present results are compared to cross section values used in recent comet models. The importance of applying accurate cross sections, including double charge exchange, to obtain absolute line-emission intensities is emphasized.     

“就矿找矿”在青海的找矿实践

正"就矿找矿"就是运用新的思维,新的理论,新的技术方法手段对已知的一种或几种找矿线索(如矿化露头、物化探异常、古采矿坑遗迹、未被证实有开采价值的矿点及正在生产的矿山周边和深部等)开展地质找矿工作,进行新的分析、新的探索.新的认识,以求发现和找到具有可供开发利用价值的矿床。近年来,随着地质勘查投入的大幅增长和找矿突破战略行动的深入实施,就矿找矿理论在实践中不断丰富完善并得到广泛应用,为新时期地质找矿     

三江北段纳日贡玛黑云母花岗斑岩LA-ICP-MS锆石U-Pb定年及其地质意义

西南三江北段是青海省重要的斑岩型铜钼矿成矿带,纳日贡玛铜钼矿是近年来在三江北段发现的与侵入岩有关的斑岩型铜钼矿。利用锆石U-Pb方法测得纳日贡玛黑云花岗斑岩的形成年龄为41.53Ma ±0.24Ma,属于喜马拉雅早期。纳日贡玛斑岩型铜钼矿的成矿时代主要在40.86~40.80Ma之间。在多期热液叠加、多期成矿作用中,纳日贡玛斑岩型铜钼矿的热液应是纳日贡玛黑云花岗斑岩（41.53Ma ±0.24Ma）和纳日贡玛斜长花岗斑岩（41.00Ma ±0.18Ma）共同提供的。由于该区有较多的中酸性岩体存在,因而确定这些侵入体的形成年龄,对于在该区寻找同时代的斑岩型铜钼矿有重要的理论意义和现实意义。     

青海西部祁漫塔格山卡尔却卡铜多金属矿床似斑状 黑云二长花岗岩LA-ICP-MS锆石U-Pb年龄

祁漫塔格卡尔却卡铜多金属矿体主要产于花岗闪长岩、似斑状黑云母二长花岗岩体与寒武纪—奥陶纪滩间山群接触部位的矽卡岩带和二长花岗岩中。本次对矿区Ⅶ号带矽卡岩与矿体紧邻的似斑状黑云母二长花岗岩体进行LA-ICP-MS锆石U-Pb测年,获得年龄为410.1Ma±2.6Ma。结合前人获得的花岗闪长岩SHRIMP锆石U-Pb年龄（237 Ma±2Ma）和矿石矿物辉钼矿Re-Os模式年龄（239Ma）,认为岩体成岩和成矿时代都发生在印支期,卡而却卡铜多金属矿成矿作用不仅与印支期中酸性侵入岩有关,也与加里东晚期酸性侵入岩有关。祁漫塔格地区矿床形成时代主要集中于加里东中晚期和印支晚期,尽管加里东期岩体在地表出露规模远没有印支期岩体规模宏大,但是加里东晚期岩体对成矿作用的贡献也应该引起足够的重视。     

甘肃龙尾沟斑岩型铜(钨)矿床成矿特征及形成环境

龙尾沟铜(钨)矿床是祁连山地区新近发现的一处斑岩型矿床,其评价及研究对祁连山地区铜矿勘查具有重要的指导和借鉴作用。本文通过对含矿斑岩年代学及地球化学、矿体产出特征及矿石物质组成、围岩蚀变等进行了系统研究,结果表明,花岗闪长斑岩形成年龄为358.7Ma;矿体呈似层状、透镜状和脉状产出,主要产于高钾碱性系列斑岩体内,并受近南北向构造控制;矿石矿物主要为黄铜矿、黄铁矿、磁黄铁矿、白钨矿,呈细脉-浸染状、浸染状产出;矿化以富铜、钨、金贫钼为特征;与成矿关系密切的围岩蚀变主要为绢英岩化,次为钾硅酸盐化和硅化;矿床成矿时代为海西早期,形成于陆内造山伸展环境。从成矿背景分析认为祁连山地区陆内造山环境所形成的斑岩型铜矿具有良好的找矿前景。     

青海祁漫塔格小圆山铁多金属矿区英云闪长岩LA-MC-ICP-MS锆石U-Pb测年及其地质意义

东昆仑祁漫塔格地区是青海省重要的矽卡岩型铁多金属成矿带,小圆山矽卡岩型铁多金属矿位于青海祁漫塔格东段。利用LA MC ICP MS锆石U Pb定年技术,获得小圆山铁多金属矿区与成矿关系密切的英云闪长岩加权平均年龄为(217.7±1.1)Ma(n=36,MSWD=2.5),厘定其形成时代为晚三叠世,属印支晚期。岩石地球化学研究表明,英云闪长岩为准铝质高钾钙碱性系列岩石。岩石明显富集大离子亲石元素(Rb、K)、LREE和活泼的不相容元素(如U、Th),相对亏损高场强元素(如Nb、Ta、P、Zr、Ti),显示了轻稀土元素强烈富集的右倾式稀土元素配分型式,具有弱的负Eu异常。青海祁漫塔格地区已有的年代学资料和区域地质构造演化特征综合表明,小圆山英云闪长岩可能形成于后碰撞构造阶段,为区域东昆仑造山带晚古生代-早中生代构造旋回的产物。