The Ore-forming Fluid of the Gold Deposits of Muru Gold Belt in Eastern Shandong, China - a Case Study of Denggezhuang Gold Deposit   总被引：1，自引：0，他引：1  

Qingdong Zeng    Jianming Liu    Hongtao Liu    Ping Shen  Lianchang Zhang 《Resource Geology》2006,56(4):375-384

Abstract. Denggezhuang gold deposit is an epithermal gold‐quartz vein deposit in northern Muru gold belt, eastern Shandong, China. The deposit occurs in the NNE‐striking faults within the Mesozoic granite. The deposit consists of four major veins with a general NNE‐strike. Based on crosscutting relationships and mineral parageneses, the veins appear to have been formed during the same mineralization epochs, and are further divided into three stages: (1) massive barren quartz veins; (2) quartz‐sulfides veins; (3) late, pure quartz or calcite veinlets. Most gold mineralization is associated with the second stage. The early stage is characterized by quartz, and small amounts of ore minerals (pyrite), the second stage is characterized by large amounts of ore minerals. Fluid inclusions in vein quartz contain C‐H‐O fluids of variable compositions. Three main types of fluid inclusions are recognized at room temperature: type I, two‐phase, aqueous vapor and an aqueous liquid phase (L+V); type II, aqueous‐carbonic inclusions, a CC₂‐liquid with/without vapor and aqueous liquid (LCO₂+VCC₂+Laq.); type III, mono‐phase aqueous liquid (Laq.). Data from fluid inclusion distribution, microthermometry, and gas analysis indicate that fluids associated with Au mineralized quartz veins (stage 2) have moderate salinity ranging from 1.91 to 16.43 wt% NaCl equivalent (modeled salinity around 8–10 wt% NaCl equiv.). These veins formatted at temperatures from 80d? to 280d?C. Fluids associated with barren quartz veins (stage 3) have a low salinity of about 1.91 to 2.57 wt% NaCl equivalent and lower temperature. There is evidence of fluid immiscibility and boiling in ore‐forming stages. Stable isotope analyses of quartz indicate that the veins were deposited by waters with δ^O and δD values ranging from those of magmatic water to typical meteoric water. The gold metallogenesis of Muru gold belt has no relationship with the granite, and formed during the late stage of the crust thinning of North China.  相似文献   

山丘型地区钉螺孳生数量与植被和土壤环境因子的关系   总被引：3，自引：0，他引：3  

蒋俊明  何亚平  费世民  黄玲玲  陈秀明  张旭东  徐嘉  何飞 《湿地科学与管理》2006,2(4):33-39

本文研究了四川仁寿山丘型地区钉螺孳生与植被和环境因素的关系。结果表明:(1)草本群落物种丰富度、草本盖度、草本高度影响钉螺的孳生数量,钉螺分布适宜的草本群落的物种丰富度为4～14,草本群落盖度为60%～100%,高度为20～50cm;(2)土壤水分含量、温度和盐分均影响钉螺的孳生数量,钉螺分布最适宜的土壤水分含量为20%～60%,温度为15～30℃,盐分为60～120ms/m;(3)各环境因子和钉螺密度曲线可以看出,物种丰富度、草本高度、草本盖度、土壤水分含量、土壤温度和盐分含量与钉螺密度间均呈现抛物线或抛物线状曲线;(4)在样地和样方水平,土壤水分含量和钉螺密度存在稳定的线性相关关系,表明土壤水分含量是影响钉螺孳生的主导因素。因此,钉螺对各环境因素存在适应范围,表明钉螺对潮湿环境具有严格的选择性和依赖性,这种生态特性和钉螺本身的生物学特征密切相连。  相似文献   

山区生态县区域协调发展的机制构建--以粤北始兴县为例   总被引：1，自引：0，他引：1  

税伟  陈烈  唐常春 《山地学报》2006,24(1):70-78

区域协调机制在不同类型地域和一种类型地域的不同的发展阶段是不同的。始兴县作为一个典型的山区生态县,工业进入加速发展时期,在此经济发展阶段的区域协调问题主要表现在:与外部区域经济、社会发展差距拉大,工业化与流域生态环境保护的矛盾已开始凸现,县政府协调区域发展的财政能力较低,区域协调机制不健全等。由此对始兴县的区域协调机制进行建构:建立健全多层次的区域协调机构;加大纵向和横向政府财政转移支付的力度;加强与相邻相关地区的协调;实施区域空间管治协调,保护城乡生态环境;科学合理选择产业,大力发展循环经济;全县推行绿色GDP考核等。  相似文献   

基于GIS的山地林道网优化配置系统   总被引：1，自引：0，他引：1  

邱荣祖  兰樟仁  黎建明 《山地学报》2006,24(6):716-720

应用系统选择永安元沙国有林业采育场的部分林班为示范,建立森林资源空间数据库.以ARC/INFO为开发平台,以山地林道网理论为指导,应用G IS技术、DBMS技术与数学规划集成技术,使用AML语言进行二次开发设计山地林道网优化配置系统,实现计算机辅助林道网配置,提高决策的科学性。  相似文献   

Secular variations of the upper crust composition: Implication of geochemical data on the Upper Precambrian shales from the Southern Urals western flank and Uchur-Maya region     

A. V. Maslov  V. N. Podkovyrov  Yu. L. Ronkin  M. T. Krupenin  E. Z. Gareev  V. M. Gorozhanin 《Stratigraphy and Geological Correlation》2006,14(2):126-149

In the mid-1980s, it was concluded based on geochemical study that Th, Sc, La concentrations and ratios Th/Sc, La/Sc and Eu/Eu* did not wary significantly in the post-Archean time. It was impossible to judge about compositional variations of upper crust during the Riphean and Vendian, because data of that time characterized a limited number of samples from the post-Archean basins of Australia, New Zealand, and Antarctic. Considered in this work are variations of Eu/Eu*, LREE/HREE, Th/Sc, and La/Sc ratios in Upper Precambrian fine-grained siliciclastic rock of the Southern Urals western flank (Bashkirian meganticlinorium) and Uchur-Maya region (Uchur-Maya plate and Yudoma-Maya belt). As is established, only the Eu anomaly in the studied siliciclastic rocks is practically identical to this parameter of the average post-Archean shale. Three other parameters plot on the Riphean-Vendian variation curves with positive and negative excursions of diverse magnitude, which do not coincide always in time. It is assumed that these excursions likely mark stages of local geodynamic activity, destruction of pre-Riphean cratons, and progressing recycling of sedimentary material during the Riphean.  相似文献   

Comment on 'Chemical remagnetization of the Upper Carboniferous–Lower Triassic Pyeongan Supergroup in the Jeongseon area, Korea: fluid migration through the Ogcheon Fold Belt' by Y.H. Park, S.-J. Doh and D. Suk     

Youngdo Park  Jin-Han Ree 《Geophysical Journal International》2006,164(3):481-483

  相似文献   

邢台矿区山字型构造的发现及其地质意义   总被引：1，自引：0，他引：1  

张纪勋  范志平 《中国煤田地质》2006,18(4):18-21

邢台山字型构造位于河北省邯邢煤田内，其前弧向ES突出，脊柱呈ES-WN走向。分别分析了山字型构造脊柱及其东、西翼反射弧构造形迹特征，对研究区找矿具有重要意义。  相似文献   

Early Proterozoic syn-and postcollision granites in the northern part of the Baikal fold area     

A. M. Larin  E. B. Sal’nikova  A. B. Kotov  L. B. Makar’ev  S. Z. Yakovleva  V. P. Kovach 《Stratigraphy and Geological Correlation》2006,14(5):463-474

Early Proterozoic granitoids are of a limited occurrence in the Baikal fold area being confined here exclusively to an arcuate belt delineating the outer contour of Baikalides, where rocks of the Early Precambrian basement are exposed. Geochronological and geochemical study of the Kevakta granite massif and Nichatka complex showed that their origin was related with different stages of geological evolution of the Baikal fold area that progressed in diverse geodynamic environments. The Nichatka complex of syncollision granites was emplaced 1908 ± 5 Ma ago, when the Aldan-Olekma microplate collided with the Nechera terrane. Granites of the Kevakta massif (1846 ± 8 Ma) belong to the South Siberian postcollision magmatic belt that developed since ～1.9 Ga during successive accretion of microplates, continental blocks and island arcs to the Siberian craton. In age and other characteristics, these granites sharply differ from granitoids of the Chuya complex they have been formerly attributed to. Accordingly, it is suggested to divide the former association of granitoids into the Chuya complex proper of diorite-granodiorite association ～2.02 Ga old (Neymark et al., 1998) with geochemical characteristics of island-arc granitoids and the Chuya-Kodar complex of postcollision S-type granitoids 1.85 Ga old. The Early Proterozoic evolution of the Baikal fold area and junction zone with Aldan shield lasted about 170 m.y. that is comparable with development periods of analogous structures in other regions of the world.  相似文献   

Avalanche Risk During Backcountry Skiing – An Analysis of Risk Factors     

Harpa Grímsdóttir  David Mcclung 《Natural Hazards》2006,39(1):127-153

Skier-triggered avalanches are the main cause of avalanche accidents in backcountry skiing. The risk of accidents during backcountry skiing was analysed statistically and related to factors such as elevation level, aspect, stability rating and the time of the year. The analysis is based on a database about terrain usage and avalanche accidents from a large heli-skiing operator in Canada, which makes it possible to study the conditional probability of accidents given the recorded pattern of terrain usage. This study shows that the historical risk of accidentally triggering an avalanche greater than size 1 depends highly on the stability rating, with the highest risk occurring during “poor” stability. The risk is greater at high elevations, and it is lower during the late season than earlier on. Skier risk does not depend as much on aspect as may be indicated from avalanche data alone. However, it is relatively high in the N–NE–E sector. These factors are not independent of each other and therefore analyses of combined factors were also performed. Questionnaires and interviews were used to gain knowledge about the terrain selection of professional mountain guides. These results indicate that when selecting terrain, guides first look at the overall shape and size of the terrain, but avalanche history of terrain and inclination are also important factors. Finally, remarks in avalanche reports were analysed, and common human factors identified.  相似文献   

对云山异常金成矿远景的分析     

孙中任  赵雪娟  吕长生 《物探与化探》2005,29(3):217-219,236

通过对云山异常区的区域构造、地质条件的了解,以及对该区地球物理、地球化学资料的分析,认为这是一处值得关注的异常区,并指出异常区中的磁异常的地质起因极可能为剖析这一异常带来转机。  相似文献