西藏邦铺大型斑岩钼-铜矿床二长花岗斑岩锆石SHRIMP定年及其地质意义   总被引：3，自引：1，他引：2  

周雄  温春齐  温泉  吴鹏宇  曹盛远  费光春  霍艳  周玉 《矿物岩石地球化学通报》2010,29(4)

利用锆石U-Pb SHRI MP定年技术,测定了西藏冈底斯斑岩铜矿带东段邦铺斑岩钼铜矿床中二长花岗斑岩的年龄,获得该含矿岩体真实侵位年龄为13.9±0.3 Ma(MSWD=3.05),属于喜马拉雅晚期。邦铺二长花岗斑岩的形成时代介于冈底斯成矿带后碰撞期伸展构造环境的斑岩体的形成时代(12~18 Ma),该年龄的厘定进一步丰富了冈底斯带岩浆活动,并为整个冈底斯成矿带岩浆岩演化历史提供年代学数据和新的启示:可以认为其与冈底斯斑岩铜矿带具有相同的动力学背景,同属于大规模的快速爆发成矿作用过程。  相似文献   

广西姑婆山地区钨锡矿床地质特征及幔源物质参与成矿显示   总被引：3，自引：0，他引：3  

张诗启  蔡明海  彭振安  徐明  陈艳  韩凤彬 《西北地质》2010,43(1):86-97

姑婆山地区钨锡矿床位于南岭钨锡成矿带西南缘,是我国重要的钨锡产地。区内有新路、水岩坝和珊瑚三个钨锡矿田,矿床类型多样。其中,锡锌硫化物型、黑钨石英脉型和钨锡石英脉型矿床较为典型,区内钨锡成矿与壳幔混源型花岗岩体和断裂关系密切。笔者在前人工作基础上,总结了区内主要钨锡矿田和典型矿床地质特征,认为钨锡矿化在空间上具有一定的分带性;通过对区内构造和矿床的D-O同位素、H e-A r同位素、Pb同位素、S同位素及流体包裹体分析,认为深大断裂可能为幔源物质上侵提供了通道,钨锡成矿与岩浆作用关系密切,幔源物质参与了区内钨锡成矿。  相似文献   

Sedimentogenesis and resource potential of Middle–Upper Bathonian reservoirs in the Middle Ob’ region     

A.E. Kontorovich  L.G. Vakulenko  V.A. Kazanenkov  M.B. Skvortsov  P.A. Yan  V.V. Bykov  A.Yu. Popov  L.S. Saenko 《Russian Geology and Geophysics》2010,51(2):147-158

This study provides a comprehensive sedimentologic analysis of the J₂ prospective horizon (Middle–Late Bathonian) in the central West Siberian Basin. Based on the extensive dataset, it was established that structural complexity of this horizon is largely caused by a variety of depositional environments. Sedimentary facies of this horizon pass upward from widespread continental at the base, through deltaic or coastal-continental, to marginal-marine at the top. Change in the paleohypsometry of the study area reflects the distribution of depositional environments, in terms of the proportions of continental, transitional, and marine deposits. The study also shows that facies variability and change in depositional settings can have a significant control on reservoir quality, as well as its vertical and lateral distribution. Using a combination of detailed GDE reconstructions, structure contour mapping on the top and base of the J₂ horizon, analyses of well test data, probability of reservoir presence, distribution of average porosity and permeability within different subenvironments, a composite map showing variations in the reservoir effectiveness in the J₂ horizon was generated.  相似文献   

REE, Mn, Fe, Mg and C, O Isotopic Geochemistry of Calcites from Furong Tin Deposit, South China: Evidence for the Genesis of the Hydrothermal Ore-forming Fluids     

Yan Shuang  Xian-Wu Bi  Rui-Zhong Hu  Jian-Tang Peng  Hang Li  Da-Hua Li    Chang-Sheng Zhu 《Resource Geology》2010,60(1):18-34

The Furong tin deposit in the central Nanling region, South China, consists of three main types of mineralization ores, i.e. skarn-, altered granite- and greisen-type ores, hosted in Carboniferous and Permian strata and Mesozoic granitic intrusions. Calcite is the dominant gangue mineral intergrown with ore bodies in the orefield. We have carried out REE, Mn, Fe, and Mg geochemical and C, and O isotopic studies on calcites to constrain the source and evolution of the ore-forming fluids. The calcites from the Furong deposit exhibit middle negative Eu anomaly (Eu/Eu*= 0.311–0.921), except for one which has an Eu/Eu* of 1.10, with the total REE content of 5.49–133 ppm. The results show that the calcites are characterized by two types of REE distribution patterns: a LREE-enriched pattern and a flat REE pattern. The LREE-enriched pattern of calcites accompanying greisen-type ore and skarn-type ore are similar to those of Qitianling granite. The REE, Mn, Fe, and Mg abundances of calcites exhibit a decreasing tendency from granite rock mass to wall rock, i.e. these abundances of calcites associated with altered granite-type and greisen-type ores are higher than those associated with skarn-type ores. The calcites from primary ores in the Furong deposit show large variation in carbon and oxygen isotopic compositions. The δ¹³C and δ¹⁸O of calcites are −0.4 to −12.7‰ and 2.8 to 16.4‰, respectively, and mainly fall within the range between mantle or magmatic carbon and marine carbonate. The calcites from greisen and altered granite ores in the Furong deposit display a negative correlation in the diagram of δ¹³C versus δ¹⁸O, probably owing to the CO₂-degassing of the ore-forming fluids. From the intrusion to wall-rock, the calcites display an increasing tendency with respect to δ¹³C values. This implies that the carbon isotopic compositions of the ore-bearing fluids have progressively changed from domination by magmatic carbon to sedimentary carbonate carbon. In combination with other geological and geochemical data, we suggest that the ore-forming fluids represent magmatic origin. We believe that the fluids exsolved from fractionation of the granitic magma, accompanying magmatism of the Qitianling granite complex, were involved in the mineralization of the Furong tin polymetallic deposit.  相似文献   

Features of ferric sulfate precipitates formed by different cultivations of Acidithiobacillus ferrooxidans     

Xin WANG  Yan LI  Anhuai LU  Changqiu WANG 《Frontiers of Earth Science》2010,4(2):152-159

This study focused on the ferric sulfate precipitates formed during the culture of Acidithiobacillus ferrooxidans (A. ferrooxidans) in a modified 9K medium by applying a potential control on the electrode. X-ray diffraction (XRD), environmental scanning electron microscope (ESEM), Raman spectroscopy (Raman) and Fourier Transform Infrared spectroscopy (FTIR) were carried out to characterize and identify the precipitates which were formed, respectively, in the electrochemical cultivation with a fixed cathode potential (bias-experiment) and in the conventional batch cultivation without cathode potential control (no-bias-experiment). The results indicated that K-jarosite presented in both experiments while NH₄-jarosite and schwertmannite were only found in the no-bias-experiment. The formation of different precipitates could be attributed to the different growth statuses and rates of A. ferrooxidans and the different concentrations of Fe³⁺. In the bias-experiment, external electrons reproduced Fe²⁺ and promoted the growth of A. ferrooxidans, thus resulting in the low Fe³⁺ concentration and the rapid depletion of NH₄ ⁺ as the nitrogen source, in which K-jarosite was preferentially formed. In the no-bias-experiment, the lower concentration of A. ferrooxidans was observed, which was due to the continuous consumption of Fe²⁺ by bacteria, thus resulting in the relatively higher Fe³⁺ and the NH₄ ⁺ concentration in culture. The high concentration of Fe³⁺ favored the precipitation of the solid solution of K-NH₄-H₃O jarosite, and led to the formation of schwertmannite after K⁺ and NH₄ ⁺ were depleted.  相似文献   

淮南板集煤矿F512断层导水性分析及地面注浆加固   总被引：1，自引：0，他引：1  

孙家应  谢长仑  黄平  谢焰 《中国煤炭地质》2010,(7):31-35

板集煤矿F512断层落差70m,存在着导通上覆新生界松散层水与下伏太原组岩溶水的威胁,同时,断层带的破碎岩体也将对巷道掘进和支护带来困难。该矿先后施工了3个水文地质钻孔进行抽水和压水试验,根据岩心鉴定成果和岩石RQD值,认为断层带的岩心较为破碎;依据抽水过程中的流量变化、水位降深值和水位恢复值等指标及压水试验中透水率分析,发现该断层的导水性较差,具有弱渗透性。参考相邻矿区的经验,决定对断层破碎岩体采用地面注浆方法进行加固。整个工种注入水泥浆1 600m3,破碎岩体得到了有效加固,巷道掘进顺利通过了F512断层。  相似文献   

http://www.sciencedirect.com/science/article/pii/S1674987110000113   总被引：3，自引：0，他引：3  

Xueqi Xi  Zhongfang Yang  Yan Liao  Yujun Cui  Yansheng Li 《地学前缘(英文版)》2010,1(1):125-132

<正>Against the current background of global climate change,the study of variations in the soil carbon pool and its controlling factors may aid in the evaluation of soil's role in the mitigation or enhancement of greenhouse gas.This paper studies spatial and temporal variation in the soil carbon pool and their controlling factors in the southern Song-nen Plain in Heilongjiang Province,using soil data collected over two distinct periods by the Multi-purpose Regional Geochemical Survey in 2005—2007, and another soil survey conducted in 1982—1990.The study area is a carbon source of 1479 t/km~2 and in the past 20 years,from the 1980s until 2005.the practical carbon emission from the soil was 0.12 Gt.Temperature,which has been found to be linearly correlated to soil organic carbon,is the dominant climatologic factor controlling soil organic carbon contents.Our study shows that in the relevant area and time period the potential loss of soil organic carbon caused by rising temperatures was 0.10 Gt,the potential soil carbon emission resulting from land-use change was 0.09 Gt,and the combined potential loss of soil carbon(0.19 Gt) caused by warming and land-use change is comparable to that of fossil fuel combustion(0.21 Gt).Due to the time delay in soil carbon pool variation,there is still 0.07 Gt in the potential emission caused by warming and land-use change that will be gradually released in the future.  相似文献   

Assessing the vulnerability of social–environmental system from the perspective of hazard,sensitivity, and resilience: a case study of Beijing,China     

Lei Yan  Xuegong Xu 《Environmental Earth Sciences》2010,61(6):1179-1186

Despite a recent increase in the number of vulnerability analyses there has been relatively little discussion of vulnerability assessment of social–environment system, especially when they face multiple hazards. In this study, we developed an applicable and convenient method to assess vulnerability of social–environment system at a regional scale. Vulnerability is quantified by measuring three critical elements (i.e. hazards, sensitivity, and resilience) through some key variables. The results showed that vulnerability is high in Miaofeng Mountain in Mengtougou District, the hills of Pinggu County and the riparian zones of the lower courses of the Beiyun and Yongding Rivers; but low in the city of Beijing and the southwestern part of the Fangshan District. Areas of very high, high, medium, and low-vulnerability account for 6.19, 25.48, 33.06, and 35.27% of the total area, respectively. The degree of vulnerability decreases in a northwest direction in mountainous areas and declines from watercourses to riparian zones along a lateral direction in the plain. Some adaptive strategies are also proposed.  相似文献   

西安地裂缝与地面沉降灾害经济损失评估   总被引：1，自引：1，他引：0  

阎文中 《上海国土资源》2010,(1):32-37

为了深入分析西安地裂缝与地面沉降灾害致灾特点及定量评价其经济损失,在中国地质调查局于2004-2006年开展的西安地区地裂缝与地面沉降调查所取得的成果资料基础上,通过综合分析研究得出,西安地裂缝与地面沉降的致灾特点具有直接性、三维破坏性、三维空间有限性、渐进性和持久性。采用终值法、影子工程法、统计推断法、重置成本法、建造成本或工程费用法、灾情对比法、间接损失与直接损失比例法和权重分解法评价得出地裂缝与地面沉降灾害在1976-2006年造成经济损失为117亿元,其中直接损失71亿元,间接损失46亿元。  相似文献   

Cassini图像中受散射光影响的7颗土星近环内卫星的天体测量          下载免费PDF全文

王志强  刘梦琪  张庆丰  吴林朋  欧钊杰  李燕  李展 《天文学报》2023,64(6):69

卡西尼号探测器携带了光学成像科学子系统(ISS: Imaging Science Subsystem), 在2004--2017年间拍摄了一些土星内卫星的图像. 部分图像中土星内卫星非常靠近土星环, 观测对象受土星环散射光影响导致测量精度差, 甚至无法测量. 由此提出一种适用于这类图像的背景消除算法, 可对受土星光环散射光影响的土星内卫星进行测量. 归算了7颗近环内卫星(土卫十(Janus)、土卫十一(Epimetheus)、土卫十五(Atlas)、土卫十六(Prometheus)、土卫十七(Pandora)、土卫三十二(Methone)和土卫四十九(Anthe))的70张ISS图像, 并与不消除散射光的方法进行了比较. 结果显示, 该方法至少可以提高43%的精度. 和喷气推进实验室的土星卫星历表\lk SAT415相比, 测量得到的赤经和赤纬方向的残差均值分别为0.72km和2.26km, 标准差分别为10.99km和11.36km.  相似文献