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131.
北京云蒙山地区花岗岩穹隆及伸展构造的探讨 总被引:9,自引:0,他引:9
北京云蒙山花岗岩为一中生代侵入的花岗岩穹隆,花岗岩穹隆的叶理普遍发育,叶理轨迹基本平行于穹隆的外部边界,并显示出从核部到边部逐渐增强,东南侧明显强于西北侧的特点。变形构造研究显示,花岗岩穹隆的边部及围岩中普遍存在不同层次及不同运动方向的伸展构造。东南侧以具河防口-水峪伸展型韧性剪切带为特征,剪切运动标志显示为从NW-SE的正剪切运动,有限应变分析估算其剪切位移量在10km以上,剪切带上部被河防口正 相似文献
132.
133.
烂泥沟金矿是以浊积岩为容矿岩石的微细浸染型金矿。有机岩石学分析表明,矿石与围岩中干酪根类型无明显差别,同属腐泥-腐植型。与围岩相比,矿石中干酪根成熟度(R0=2.74%-3.06%)和含金性(6.15-24.8μg/g)均较高;干酪根总含金量在全岩中所占的比例是围岩高于矿石。氯仿沥青“A”的检测说明,矿石样品中可溶性有机质形成于强还原和高盐度环境,沥青质和含硫有机化合物发育。研究认为,干酪根含金性与碳的活化有关;不饱和的有机基因对金的动一定转换可能具有重要意义。 相似文献
134.
坡地农林复合系统的结构类型与效益分析─以长江三峡库区坡地农业为例 总被引:4,自引:0,他引:4
本义认为现代术语的农林复合系统来源于生产实践,体现了农业与林业的有机结合、品种生态和经济的有机结合、产品多样化以及管理科学化4个方面相统一的特点。文章在分析三峡库区农林复合系统的类型结构基础上,提出了农林复合系统可以进行层次结构划分的观点。最后,以典型案例研究方法入手,对1种农林结构类型进行效益分析,结果表明,采用植物篱农林复合坡地系统,是现阶段生产力水平下实现坡地生态经济协调发展的有效途径,值得广泛推广。 相似文献
135.
冀西北长城纪宣龙式铁矿层中微体植物化石的发现及其意义 总被引:10,自引:0,他引:10
本文研究的是笔者等在冀西北长城系串岭沟组宣龙式铁矿层中发现的微体植物化石,这些化石都保存在铁质叠层石(肾状赤铁矿)和铁质核形石(鲕状赤铁矿)的基本层中。微化石以丝状体为主,部分为球状体。归属于原核生物蓝藻门颤藻科的两个属和色球藻科的一个属。化石层同位素年龄约在1800—1757Ma。这些化石与北美冈弗林特组微化石比较,既有些相似,又有些区别。该化石的发现为研究铁矿的成因,指示沉积环境及层位对比都很有意义。 相似文献
136.
矿物标型六性及其在胶东金矿中的应用 总被引:2,自引:0,他引:2
目前矿物标型研究和应用已进入一个新的阶段。作者从哲学的高度,把国内外矿物标型特征的分散研究加以集中概括和总结,提出了“矿物标型六性”的普遍规律,即普遍性、特殊性、变化性、相应性、继承性和分带性,对矿物标型特征研究具重要的指导意义。这些规律在胶东金矿中得到广泛应用,并已取得良好效果。 相似文献
137.
138.
H. Tan D. Feng J.S.J. van Deventer G.C. Lukey 《International Journal of Mineral Processing》2006,80(2-4):153-168
The anodic and cathodic behaviour of pyrite with clay and different carbon coatings of activated carbon, graphite and carbonaceous matter in cyanide medium was investigated using the potentiodynamic method. The presence of clay coating did not change the polarisation curve appearance for either the anodic oxidation of pyrite or the cathodic reduction of oxygen or the potential of the current plateau, but only decreased the plateau current especially at a higher coating thickness. The presence of the carbon coatings marginally shifted the rest potential for pyrite to a more anodic position and slightly changed the polarisation curve appearance for pyrite oxidation. The current density for pyrite oxidation largely increased in the presence of the carbon coatings, the potential at the plateau shifted to more cathodic positions, and the plateau width became smaller. These effects became more noticeable at a higher coating thickness. The activated carbon, graphite and carbonaceous matter coatings performed similarly in affecting pyrite oxidation at a similar thickness. The carbon coatings significantly increased the limiting current densities for oxygen reduction on pyrite, and the limiting current plateau became steeper at a higher coating thickness. The carbon coatings increased the limiting current density for oxygen reduction to a similar extent at a low coating thickness, but increased to varied extents at a higher coating thickness. The carbon coatings also greatly increased the cathodic current density for gold reduction on pyrite. The enhancement of pyrite oxidation and oxygen or gold reduction on pyrite by the carbon coatings was likely attributed to the electrochemical interaction between pyrite and the carbon materials with electron-rich surfaces and high conductivity. The presence of the carbon coatings significantly increased the oxidation of pyrite in aerated cyanide solutions and the preg-robbing of pyrite especially at a higher coating thickness. 相似文献
139.
Hong-Rui Fan Fang-Fang Hu Kui-Feng Yang Kai-Yi Wang 《Journal of Geochemical Exploration》2006,89(1-3):104
The giant Bayan Obo REE–Nb–Fe deposit consists of replacement bodies hosted in dolomite marble made up of magnetite, REE fluorocarbonates, fluorite, aegirine, amphibole, calcite and barite. Two or three phase CO2-rich, three phase hypersaline liquid–vapor–solid, and two phase liquid-rich inclusions have been recognized in mineralized fluorite and quartz samples. Microthermometry measurements indicate that the carbonic phase in CO2-rich inclusions is nearly pure CO2. Fluids involving in REE–Nb–Fe mineralization at Bayan Obo might be mainly of H2O–CO2–NaCl–(F–REE) system. Coexistences of brine inclusions and CO2-rich inclusions with similar homogenization temperatures give evidence that immiscibility happened during REE mineralization. An unmixing of an original H2O–CO2–NaCl fluid probably derived from carbonatitic magma. The presence of REE-carbonates as an abundant solid in fluid inclusions shows that the original ore-forming fluids are very rich in REE, and therefore, have the potential to produce economic REE ores at Bayan Obo. 相似文献
140.
Postcollisional flow of aqueous fluid within ultrahigh-pressure eclogite in the Dabie orogen 总被引:1,自引:0,他引:1
Tian-Shan Gao Song-Shan Wang Bing Gong Yuan-Bao Wu Yong-Fei Zheng 《Journal of Geochemical Exploration》2006,89(1-3):115
A combined study of chronometric dating and oxygen isotope analysis for minerals from vein and host eclogite as well as regional country-rock gneiss in the Dabie orogen provides a direct constraint on timing of fluid flow in this orogen formed by continental collision. Oxygen isotope ratios of vein minerals are significantly lower than those of the host eclogite, but comparable with those of the regional gneiss. This suggests the veining fluid came from the regional gneiss (i.e. exhumed slab itself) rather than the host eclogite. While zircon U–Pb and phengite Ar–Ar dating yields ages of 214 to 222 Ma for the eclogite and gneiss, the vein gives a quartz–muscovite Rb–Sr isochron age of 181 Ma and a muscovite K–Ar age of 179 Ma. Thus the veining postdates the Triassic ultrahigh pressure metamorphic event, witnessing postcollisional fluid flow after the orogenic cycle of continental collision. 相似文献