紫阳-岚皋地区碱中性岩地质特征及其含矿(铌钽)性研究   总被引：1，自引：0，他引：1  

邓盛波  王炜红  汪显均 《陕西地质》2003,21(2):19-26,32

陕西紫阳县至岚皋县一带，分布着东西长160余千米、南北宽20～40千米的古生代碱中性岩浆岩带。通过对碱中性岩浆岩的地质特征及其铌钽等稀有金属含矿性调查和研究，认为该岩浆岩带是本区重要的铌钽成矿区，碱中性岩浆岩是本区主要铌钽含矿岩体，碱中性岩具铌钽稀有金属矿化，伴镧铈稀土金属矿化。  相似文献   

金属因素在激电异常评价中的应用   总被引：2，自引：0，他引：2  

杨天春  吕绍林  姚成华  王齐仁 《物探与化探》2003,27(4):305-306

当激电异常较为复杂时,利用η_s(或F_s)这些激电法的基本参数难以对异常源的性质进行合理的解释.通过具体实例,说明应用激电法的二次信息--金属因素解释复杂激电异常的有效性.金属因素能将矿致异常与非矿致异常分离,对异常的定性及定量解释有很好的作用.  相似文献   

论金属矿物生物组构分类体系          下载免费PDF全文

胡晓强陈洪德  帅德权 《地质与勘探》2003,39(3):31-34

探讨了金属矿物生物组构的分类体系，将金属矿物的生物组构分为：(1)金属矿物的生物有机胶体组构，由生物直接成矿作用形成；(2)交代作用成因的金属矿物生物组构，由生物间接成矿作用形成。组构又分为结构和构造两个亚类。以典型的实例资料叙述了各种金属矿物生物组构的特征。  相似文献   

Fluid mixing as the mechanism of formation of the Dajing Cu-Sn-Ag-Pb-Zn ore deposit,Inner Mongolia ——Fluid inclusion and stable isotope evidence   总被引：2，自引：0，他引：2  

刘伟  李新俊  谭骏 《中国科学D辑(英文版)》2003,46(7)

Since the 1990s, interest in the magmatic fluids and their relation to mineralization has been re-aroused[1—6]. Studies on stable isotopes of low-sulfidation deposits commonly show the predominance of meteoric water[7]. Paradoxically, the evidence for me…  相似文献   

Exploration and discovery in Yellowstone Lake: results from high-resolution sonar imaging, seismic reflection profiling, and submersible studies     

L. A. Morgan  W. C. Shanks  III  D. A. Lovalvo  S. Y. Johnson  W. J. Stephenson  K. L. Pierce  S. S. Harlan  C. A. Finn  G. Lee  M. Webring  B. Schulze  J. Dühn  R. Sweeney  L. Balistrieri 《Journal of Volcanology and Geothermal Research》2003,122(3-4):221-242

‘No portion of the American continent is perhaps so rich in wonders as the Yellow Stone’ (F.V. Hayden, September 2, 1874)Discoveries from multi-beam sonar mapping and seismic reflection surveys of the northern, central, and West Thumb basins of Yellowstone Lake provide new insight into the extent of post-collapse volcanism and active hydrothermal processes occurring in a large lake environment above a large magma chamber. Yellowstone Lake has an irregular bottom covered with dozens of features directly related to hydrothermal, tectonic, volcanic, and sedimentary processes. Detailed bathymetric, seismic reflection, and magnetic evidence reveals that rhyolitic lava flows underlie much of Yellowstone Lake and exert fundamental control on lake bathymetry and localization of hydrothermal activity. Many previously unknown features have been identified and include over 250 hydrothermal vents, several very large (>500 m diameter) hydrothermal explosion craters, many small hydrothermal vent craters (1–200 m diameter), domed lacustrine sediments related to hydrothermal activity, elongate fissures cutting post-glacial sediments, siliceous hydrothermal spire structures, sublacustrine landslide deposits, submerged former shorelines, and a recently active graben. Sampling and observations with a submersible remotely operated vehicle confirm and extend our understanding of the identified features. Faults, fissures, hydrothermally inflated domal structures, hydrothermal explosion craters, and sublacustrine landslides constitute potentially significant geologic hazards. Toxic elements derived from hydrothermal processes also may significantly affect the Yellowstone ecosystem.  相似文献   

浙江桐庐晚奥陶世晚期沉积层序和沉积环境分析   总被引：3，自引：0，他引：3  

范代读  李从先  蔡进功  邓兵  罗璋 《沉积学报》2003,21(2):247-254

文昌组上段顶部是一套潮汐层理非常发育的泥质砂岩或砂质泥岩,存在双向交错层理,层面有雨痕,应为潮坪沉积。潮坪沉积由小型层序构成,小型层序又是由砂、泥质单层组成。砂质单层底部通常为岩性突变面或侵蚀面,砂质纹层较厚,其中可见对称波痕或泥砾;向上砂质纹层变薄,过渡到泥质单层。砂质单层形成于暴风浪时期,泥质单层是风浪衰减后恢复正常的潮汐沉积。因此,小型层序从成因上说是一风暴层序。碎屑成份、砾石成份分析表明沉积物均来自华夏古陆的沉积岩和变质岩基底。物源一致,岩层产状变化不大,反映文昌组沉积环境稳定。岩性、粒度分析表明文昌组是一向上变细、由浅海高能环境向近岸低能环境过渡的沉积层序。文昌组下段为浅海砂岩沉积,上段顶部为潮坪沉积。二者之间是一套夹砾岩透镜体的泥质粉细砂岩,其沉积环境应介于浅海和滨岸之间,为水下岸坡沉积。砾岩层只是大的沉积旋回中出现的事件性水下冲积物。  相似文献   

冀北地区金矿床He、Ar、Pb同位素组成及其成矿物质来源   总被引：13，自引：0，他引：13  

王宝德  牛树银  孙爱群  李红阳 《地球化学》2003,32(2):181-187

成矿物质来源一直是成矿理论研究和找矿实践的焦点问题。选择了冀北地区3个幔枝构造金矿集中区11个金矿床黄铁矿及部分围岩进行了He、Ar同位素测定。研究表明,冀北地区主要金矿的3He/4He的值域为(0.93～7.30)×10-6,平均3.55×10-6;R/Ra=0.66～4.93,平均2.53;40Ar/36Ar=426～2073,40Ar平均为8.20×10-7cm3/g,4He/40Ar平均为2.17。矿区外围片麻岩和花岗岩的3He/4He值仅为(0.001～0.55)×10-6,反映来源上有明显差别。3He和4He在He同位素浓度图上落于地幔区附近。64个Pb同位素数据表现为矿质以幔源为主,确有部分壳源物质加入。研究认为,本区成矿物质应源于地球深部,随地幔柱多级演化,深部成矿流体由地球深部迁移到浅部,期间不可避免地存在壳幔流体的混合作用,故其值域往往界于地幔和地壳之间。  相似文献   

Lithology and palynology of Neogene sediments on the narrow edge of the Kitakami Massif (basement rocks), northeast Japan: Significant change for depositional environments as a result of plate tectonics     

Koji Yagishita  Akiko Obuse  Hiroshi Kurita 《Island Arc》2003,12(3):268-280

Abstract A controversial stratigraphic section, the Taneichi Formation, is exposed along the Pacific Coast of northeastern Honshu, the main island of the Japanese Archipelago. Although most sediments of the formation have long been dated as late Cretaceous, the northern section of it has been assigned to (i) the Upper Cretaceous; (ii) the Paleogene; or (iii) the Neogene. In the present report, we present the data of palynological and sedimentological studies, showing that the northern section should be assigned to the Neogene. A more important point in the present study is that we invoke some basic principles of fluvial sedimentology to resolve this stratigraphic subject. The lignite layers full of Paleogene–Miocene dinoflagellate cysts and pollen assemblages drape over the boulder‐sized (>40 cm in diameter) clasts in the northern section. However, the layers totally consist of aggregates of small lignite chips, indicating that the lignites are allochthonous materials. The mega‐clasts with derived microfossils in the lignites are thought to have been deposited as Neogene fluvial (flood) sediments in the newly formed Japanese Archipelago. Prior to the Miocene, the northern Honshu was part of the Eurasian Plate, thus the boulder‐sized clasts cannot be envisaged as long river flood deposits along the continental Paleogene Pacific Coast. Instead, the mega‐clasts with the draping lignites were probably derived from nearby Miocene highlands in the newly born island arc.  相似文献   

Sea-level changes and hydrothermal sedimentary mineralization of large-superlarge ore deposits among Sinian to Triassic in South China   总被引：2，自引：0，他引：2  

陈多福  陈先沛  陈光谦 《中国科学D辑(英文版)》2003,46(Z1)

Among the Sinian to Triassic strata in South China, the stratiform, quasi-stratiform and lenticular metallic deposits in association with hydrothermal sedimentation mainly occur in the four periods: (1) the Sinian Datangpo interglacial period, (2) the early period of Early Cambrian, (3) the late period of Middle Devonian to early period of Late Devonian,and (4) the late period of Early Permian. The four mineralization periods all happened around the maximum flooding period in the third-order seal-level cycle during the ascending stage in the first-order sea-level cycle. The deep seawater layer, starved and non-compensatory basin, low sedimentary rate, and low energy and anoxic environment during the maximum flooding period are very suitable for the formation and preservation of large to superlarge hydrothermal sedimentary deposits. The maximum flooding period also coincided with the intensified regional tectonism, extensive deep magmatism and hydrothermal sedimentation, which provide, for the formation of large to superlarge hydrothermal sedimentary deposits through the rapid accumulation of hydrothermal sediments, the needed dynamics, ore-forming materials and favorable passway for hydrothermal fluids to enter the basin.  相似文献   

易门式大型铜矿床构造成矿动力学模型   总被引：5，自引：1，他引：5  

韩润生  刘丛强  马德云  王红才  马更生 《地质科学》2003,38(2):200-213

针对金属矿床隐伏矿定位预测的关键问题,在提出构造成矿动力学的分支学术方向的基础上,以易门式大型铜矿床为例,从成矿地质背景、矿田构造、构造地球化学和成矿构造应力场等方面进行构造成矿动力学研究,阐述在构造应力场控制下成矿流体运移和聚集的规律。构造地球化学研究认为,构造地球化学异常反映矿体的原生晕;构造地球化学异常受构造控制,其分带特征可指示成矿流体的流向,并提供矿床成因和隐伏矿(化)体相对埋深的信息。构造应力场的控矿特征主要表现在:构造应力场导致控矿构造的形成,并驱动成矿流体的运移;构造应力场控制了成矿能量场;应力和能量的高值集中区分布特点可反映某些构造型式。在此基础上建立构造成矿动力学模型,概括隐伏矿成矿预测准则,据此提出若干重点找矿靶区和靶位,其中部分靶区得到工程验证,表明构造成矿动力学方法对隐伏矿定位预测和评价具有重要的指导意义。  相似文献