赣南崇义—大余—上犹矿集区不同类型含矿石英中白云母40Ar/39Ar年龄及其地质意义   总被引：14，自引：0，他引：14  

刘善宝  王登红  陈毓川  李建康  应立娟  许建祥  曾载淋 《地质学报》2008,82(7):932-2008-01-30

崇义—大余—上犹矿集区是世界著名的黑钨矿床集中区,本文选择钨锡多金属硫化物石英脉型（柯树岭和漂塘矿床）和锡钨石英脉型（仙鹅塘矿床）3个矿床石英中的白云母开展40Ar/39Ar年代学研究,测得坪年龄分别是：钨锡多金属硫化物石英脉型是 158.9 ± 1.4 Ma（漂塘）、158.8 ± 1.2 Ma（柯树岭）;钨锡石英脉型的是231.4 ± 2.4 Ma（仙鹅塘）,在反等时线图上,其对应的截距年龄分别是158.8 ± 1.6 Ma、158.7 ± 1.9Ma和232.5 ± 2.4 Ma。由此表明,在崇余犹矿集区内存在两个不同成矿时期,即以黑钨矿为主的多金属硫化物石英脉型矿床形成于中侏罗世,集中于160~150Ma之间,与南岭地区钨锡矿床的主成矿期是一致的;而以锡石为主的,并含有大量白钨矿的石英脉型矿床可形成于印支期  相似文献   

柴达木盆地北缘侏罗系不同沉积环境烃源岩生物标志物特征及其应用   总被引：2，自引：0，他引：2  

曹剑  边立曾  胡凯  刘云田  汪立群  杨少勇  陈琰 《地质学报》2008,82(8):1121-1128

柴达木盆地北缘地区侏罗系(中下侏罗统)的优质烃源岩主要发育于湖相与三角洲相环境。研究了不同时代、不同沉积环境中烃源岩的生物标志物组成特征,结果发现,有3类化合物的分布与组成差异显著,包括三环萜烷(C19、C20、C21)的分布型式、重排藿烷的丰度以及规则甾烷的相对组成。其中,不同时代的差异主要体现在规则甾烷组成上;而不同沉积环境的差异主要体现为三环萜烷(C19、C20、C21)的分布型式及重排藿烷的丰度。分析认为,这些差异与烃源岩的沉积环境及其生源组成有密切关系。据此,初步将这些参数应用于两方面研究,一是为划分地层沉积环境提供“生物标志物相标志”,二是研究油源对比,取得良好效果。因此,本文研究结果具有重要实用价值与参考意义。  相似文献   

蒙古塔木察格坳陷白垩系震积岩特征及其地质意义   总被引：5，自引：1，他引：4  

王化爱  钟建华  陈鑫  高玉飞 《地质学报》2008,82(8):1088-1094

通过岩芯观察,结合构造背景研究,在蒙古塔木察格坳陷白垩纪地层中识别出震积岩。震积岩的主要标志有微同沉积断裂、同沉积塑性变形构造、液化脉、震积枕状及伴生构造等。通过对塔219 井、塔1943 井等岩芯的系统观察,建立了蒙古塔木察格坳陷白垩系震积岩的垂向序列。震积岩的垂向序列自下而上依次为砂岩脉（砂火山）层段、水塑性褶皱变形层段、斧式构造层段、滑塌构造层段、阶梯状微断层和震裂缝层段、准原地沉积湖泊津浪丘状层理和内碎屑角砾岩层段、异地沉积震浊积岩层段,对应于地震由强变弱的一个变化过程。震积岩的发现具有重要的研究意义,有助于分析盆地边界断裂的强烈活动时期。  相似文献   

对松辽盆地钱家店凹陷铀成矿作用的重新认认识     

陈晓林  方锡珩  郭庆银  夏毓亮  庞雅庆  孙晔 《地质学报》2008,82(4):553-561

钱家店凹陷中的含矿层位主要为上白垩统姚家组,前人认为其中的红色砂岩为原生成因,但大量的证据证实砂岩原生应以灰色为主,红色砂岩为后生氧化蚀变造成,并控制着钱家店铀矿床铀矿化的产出.在此基础上建立该矿床的后生蚀变分带,依次为红色蚀变带、黄色蚀变带、灰白色蚀变带、过渡带、原生带,红色蚀变带为主要的氧化带,铀矿化主要集中在过渡带.平面上铀矿化主要分布于层间氧化带前锋线附近的位置,并在氧化舌状体的前端和两个氧化舌状体之间存在铀的富集.文章最后还建立了该矿床的成矿模式,并对区域上层间氧化带的展布进行了讨论.  相似文献   

Using ALSM to map sinkholes in the urbanized covered karst of Pinellas County,Florida—1, methodological considerations   总被引：1，自引：0，他引：1  

Larry D. Seale  Lee J. Florea  H. L. Vacher  Robert Brinkmann 《Environmental Geology》2008,54(5):995-1005

Comparison of a database of interpreted sinkholes made using airborne laser swath mapping (ALSM) with databases of sinkholes made from interpretation of aerial photographs reveals substantial disagreement. The discrepancies involve the location, number, areas, and circularity of interpreted sinkholes. Methodological factors that contribute to the discrepancies include blockage of ALSM laser returns in thick vegetation, multi-path reflections, and misrepresentation of the true extent of sinkholes. Comparison of two ALSM-derived databases made (1) independently from versus (2) in combination with earlier air photo analysis in undeveloped regions had the following result: one-fourth of the sinkholes interpreted by using the composite method were missed by the independent analysis, and one-third of the sinkholes that were interpreted from the independent analysis were not interpreted as sinkholes using the composite method. Subjective interpretation leads to a high level of uncertainty such that the results of the remote sensing studies are suspect, if not invalid.  相似文献   

Hydrochemical characteristics and the effects of irrigation on groundwater quality in Harran Plain,GAP Project,Turkey     

M. Irfan Yesilnacar  M. Said Gulluoglu 《Environmental Geology》2008,54(1):183-196

Improper design, faulty planning, mismanagement and incorrect operation of irrigation schemes are the principle reasons for the deterioration of groundwater quality in a large number of countries, in particular in semi-arid and arid regions. The aim of this study is to determine the dimensions of groundwater quality after surface irrigation was begun in the semi-arid Harran Plain. Physical and chemical parameters of the groundwater including pH, temperature, electrical conductivity (EC), sodium, potassium, calcium, magnesium, chloride, bicarbonate, sulphate, nitrate, nitrite, ammonium, total phosphorus, total organic carbon and turbidity were determined monthly during the 2006 water year. The quality of the groundwater in the study area was assessed hydrochemically in order to determine its suitability for human consumption and agricultural purposes. In the general plain, the EC values measured were considerably above the guide level of 650 μS/cm, while nitrate in particular was found in almost all groundwater samples to be significantly above the maximum admissible concentration of 50 mg/l for the quality of water intended for human consumption as per the international and national standards. Total hardness reveals that a majority of the groundwater samples fall in the very hard water category. Interpretation of analytical data shows that Ca–HCO₃ and Ca–SO₄ are the dominant hydrochemical facies in the study area.  相似文献   

Delineation of groundwater protection zones by the backward particle tracking method: theoretical background and GIS-based stochastic analysis   总被引：1，自引：0，他引：1  

Konstadinos N. Moutsopoulos  Alexandra Gemitzi  Vassilios A. Tsihrintzis 《Environmental Geology》2008,54(5):1081-1090

The backward particle tracking method, an effective and powerful tool that can be used to delineate groundwater protection zones, is presented. The theoretical background and insights on the applicability of this method are provided. Moreover, the present work enriches the backward particle tracking method with an uncertainty analysis concerning the porosity values, applying a Monte Carlo (MC) approach, coupled with the use of geographical information systems (GIS). As an application example, a wellfield in the Komotini area, Greece, is investigated. The present study may serve as a potential guideline for wellfield delineation, particularly in areas like Greece where lack of data related to the hydrogeological system is often a problem.  相似文献   

Upcoming international events     

Anne Marie de Grosbois 《Environmental Geology》2008,54(5):1121-1126

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Case history of controlling a landslide at Panluo open-pit mine in China     

Zuoan Wei  Guangzhi Yin  Ling Wan  Louyan Shen 《Environmental Geology》2008,54(4):699-709

Controlling of landsides safely and economically is a great challenge to mine operators because landslides are major geological problems especially in open-pit mines. In this paper, a case history at Panluo open-pit mine is presented in detail to share the experiences and lessons with mine operators. Panluo open-pit mine is located in the southwestern Fujian province of China. It is the largest open-pit iron mine in the Fujian province and was planned in 1965 and is in full operation from 1978. In July 1990, an earthquake of magnitude 5.3 in Taiwan Strait and big rainstorms impacted the mine slope, causing tension cracks and rather large-scale failures, and forming a U-shaped landslide. Total potential volume was estimated to be up to 1.0 × 10⁶ m³. This directly threatened the mine production. In order to protect the mine production and the dwellers’ safety around, a dynamic comprehensive method was implemented including geotechnical investigations, in-situ testing and monitoring, stability analysis, and many mitigation and preventive measures. These measures slowed down the development and further occurrence of the landslide. The results showed that the landslides were still active, it was slowed with the control measures and moved rapidly with rainfall and mining down. However, no catastrophic accidents occurred and the pit mining was continued till it was closed at the elevation of 887 m in 2000. As a successful case of landslide control at an open-pit mine for 10 years, this paper reports the controlling measures in details. These experiences of landslide control may be beneficial to other similar mines for landslide control.  相似文献   

The largest karst cave discovered in a tunnel during motorway construction in Slovenia’s Classical Karst (Kras)   总被引：1，自引：0，他引：1  

Martin Knez  Tadej Slabe  Stanka Šebela  Franci Gabrovšek 《Environmental Geology》2008,54(4):711-718

Karst researchers of the Karst Research Institute ZRC SAZU are regularly consulted during the planning of Slovenia’s motorways and invited to observe and monitor construction in the karst areas. More than 350 caves have been discovered in the course of building 60 km of new motorways over the past decade. Access to the most important caves is preserved by concrete tubes closed with metal covers at the roadside. The largest cave system in a tunnel, named LC-S647, is almost entirely preserved. The protection of this cave will serve as a good example for the preservation of natural heritage in the future. Construction work for the motorway uncovered a high degree of karstification. In particular, the discovery of this cave in the Kastelec tunnel LC-S647 showed the existence of a major cave system in the geological and speleological past. A number of unconnected passages have also been found. Caves discovered during highway construction have brought new knowledge about the cavernosity and the geological history of this part of the karst.  相似文献