Water and sediment quality assessment of the Axios River and its coastal environment   总被引：1，自引：0，他引：1  

A. P. Karageorgis  N. P. Nikolaidis  H. Karamanos  N. Skoulikidis   《Continental Shelf Research》2003,23(17-19):1929

The Axios River (Axios R.) receives substantial loads of nutrients, heavy metals and other compounds, resulting from anthropogenic activities within its catchment. Long-term trends in nutrients were assessed. Dissolved and particulate fluxes of nutrients and selected metals to the Thermaikos Gulf were calculated and finally, data evaluation with water and sediment quality criteria was performed. Dissolved nutrient concentrations exhibited intra-annual variations related to the agricultural practices of the drainage area with elevated autumn–winter NO₃ concentrations (related to fertilizers applied early spring) and high levels of total phosphorous in the summer attributed to point source pollution. Long-term inter-annual variability showed a 2.5-fold increase in nitrate concentration, coupled with a 3-fold decrease in water discharge. Elevated concentrations of dissolved Pb and As have been observed in the Axios R., and freshwater quality criteria for Pb were exceeded. Stream sediments exhibited high contents for Zn, Cr, Pb, and As, mainly originating in tailings and industrial effluents. On the other hand, a considerable portion of the heavy metals is derived from the weathering of ultra-mafic ophiolite complexes. Similar patterns were observed in the Thermaikos Gulf sediment chemistry; the geochemical signatures of the Axios and Aliakmon Rivers (Aliakmon R.), in respect to their contribution in heavy metals, were identified, as well as the impact of the Thessaloniki city. Quality criteria for both river and marine sediments were violated for As and Cr. Overall, the water and sediment quality of the Axios R. and the Thermaikos Gulf have been impacted by anthropogenic activities in the hinterland. The coastal waters and sediments do not appear to pose any threat to human health and aquatic life, however, the need for regular monitoring is highly recommended.  相似文献   

通化南部金矿成矿特点及找矿方向探讨     

李东见  张成国 《吉林地质》2003,22(1):1-7

本文通过分析通化南部金矿成矿特点,并把容矿层位、围岩蚀变、控矿构造作为在通化南部寻找金矿的三要素。在重点分析上述三要素对寻找金矿的重要性基础上,提出在通化南部寻找金矿的远景地带。  相似文献   

吉林省临江市大松树金矿地质特征及找矿标志     

李卫东  王来云  李秋红 《吉林地质》2003,22(1):23-31

详细地描述了矿床的地质特征、金矿物特征及赋存状态。根据矿物共生组合划分出成矿期及成矿阶段,分析了控矿的各种因素,确定了找矿的各种标志及采取的手段,特别是采用土壤汞气测量和激电方法能确定深部矿体,为今后在该地区寻找此类型金矿床提供了方法,指明了方向。  相似文献   

氡气测量在工程地质中的应用--以西南某水电站右坝肩稳定性研究为例   总被引：3，自引：1，他引：3  

周雄华  王小群  刘华军  魏云杰 《铀矿地质》2004,20(1):45-50

本文分析了氡气测量的原理和氡气异常与不同地质现象的关系 ,提出了氡异常的判据与特征 ,并结合工程实例探讨了氡气测量在工程地质中的重要作用。  相似文献   

热水沉积铁白云石微斜长石岩的发现及其找矿意义   总被引：3，自引：0，他引：3  

夏学惠 《岩石矿物学杂志》1998,17(1):41-47

铁白云石微斜长石岩作为一种特殊岩石类型,在辽东元古宙裂谷块状硫化物矿床中与成矿关系密切。岩石呈韵律层状,富含Ｋ、Ｂ、Ｓｉ,在Ａｌ２Ｏ３—ＳｉＯ２—（ＣａＯ＋ＭｇＯ）和Ｆｅ—Ｍｎ—（Ｃｕ＋Ｎｉ＋Ｃｏ）三角图上均落入热水沉积岩区。稀土元素具有铈负异常、轻稀土元素富集等特征。硅同位素地球化学显示该岩石为热水沉积成因。此类岩石做为一种热水沉积岩具有重要的找矿意义,依据这一标志在老矿山外围已经找到了硫化物矿体。  相似文献   

弧前盆地研究进展综述   总被引：6，自引：1，他引：5  

张传恒  张世红 《地质科技情报》1998,17(4):1-7

综述了弧前盆地的沉降机制,充填序列及主要识别标志,沉降机制分析表明,其沉降速率总体呈下降趋势。沉积充填序列总体表现为一向上变粗,变浅的巨层序,其具体发育规律主要受增生槛高程,充填速率与沉降速率比值控制,特殊的构造部位,弱的变形,变质和富有特色的沉积序列,砂岩碎屑组分是判别化石弧前盆地的主要标志。  相似文献   

凭祥金矿地质特征与找矿标志     

黄启勋  韦永敏 《南方国土资源》1998,(2)

在广西凭祥市早三叠世火山岩中首次发现的数个具工业价值的微细粒型金矿,肯定了它是我区新的找金层位,拓宽了找金的新领域。根据地质勘查资料,通过对龙塘、山更土两个主要矿床的剖析,论述该类金矿成矿的区域地质背景、矿床地质特征、找矿标志及找矿前景。  相似文献   

四川西部主要类型金矿区域化探找矿模型   总被引：5，自引：0，他引：5  

陈德友 《四川地质学报》1998,(2)

四川西部主要类型金矿区域化探找矿模型是区内东北寨、马脑壳等３０多处金矿床（点）区域化探异常特征、变化规律和找矿标志的抽象概括。其表格式、图形式和数学式模型清楚、形象地显示了区内主要大中型金矿床的主要找矿标志的信息,是这一区域金异常筛选与评价的基本准则。  相似文献   

Elastic and inelastic drift performance optimization for reinforced concrete buildings under earthquake loads     

Chun‐Man Chan  Xiao‐Kang Zou 《地震工程与结构动力学》2004,33(8):929-950

This paper presents an effective optimization technique for the elastic and inelastic drift performance design of reinforced concrete buildings under response spectrum loading and pushover loading. Attempts have been made to develop an automatic optimal elastic and inelastic drift design of concrete framework structures. The entire optimization procedure can be divided into elastic design optimization and inelastic design optimization. Using the principle of virtual work, the elastic drift response generated by the response spectrum loading and the inelastic drift response produced by the non‐linear pushover loading can be explicitly expressed in terms of element sizing design variables. The optimization methodology for the solution of the explicit design problem of buildings is fundamentally based on the Optimality Criteria approach. One ten‐story, two‐bay building frame example is presented to illustrate the effectiveness and practicality of the proposed optimal design method. While rapid convergence in a few design cycles is found in the elastic optimization process, relatively slow but steady and smooth convergence of the optimal performance‐based design is found in the inelastic optimization process. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

巴音宝力格隆起带中新生代盆地砂岩铀矿类型及区域预测判据   总被引：1，自引：0，他引：1  

孙泽轩  姚毅锋 《矿物岩石》2004,24(4):43-48

巴音宝力格隆起带与蒙古人民共和国境内塞音山达砂岩型铀矿成矿省位于同一大地构造单元。隆起带上中新生代盆地内找矿目的层巴彦花组中发育了冲积扇、辫状河、三角洲与湖泊4种沉积体系；其中发育了潜水氧化带与潜水层间氧化带2种氧化带类型，前者主要发育于冲积扇、基底式古河道以及巴彦花组与上第三系不整合面部位碎屑岩中，后者主要发育于三角洲与建造式古河道碎屑岩中。隆起带上中新生代盆地内地表有铀矿化显示，深部铀矿化信息丰富，层巴彦花组中可能存在潜水层间氧化带与古河道2种砂岩铀矿类型。文中概括总结了隆起带上中新生代盆地内潜水层间氧化带与古河道砂岩型铀矿区域预测判据，提出了东部与西部地区以寻找潜水层间氧化带砂岩型铀矿为主，兼顾寻找发育于冲积扇前缘辫状河沉积体系碎屑岩中的建造式古河道砂岩型铀矿，中部地区以寻找基底式古河道砂岩型铀矿为宜的找矿思路。  相似文献