GEOCHEMICAL EFFECTS OF MAJOR ELEMENTS DURING FLUID-ROCKS INTERACTION IN MARINWOBO FAULT IN THE SOUTH MARGIN AREAS OF ALTAI MOUNTAINS

There are four types of metamorphic rocks in the Marinwobo fault, i. e, cataclasite, mylonite,mictosite and migmatitic granite, and the formation of these rocks is due to the progressive metamorphism of the pyroclastics. The fluids play a very important role in the metamorphic process of these rocks in the Marinwobo fault, the most important feature is that the fluids not only result in the migration of the major elements of the deformation rocks, but also result in the volume loss of the deformation rocks in the deformation process. Thus the migration laws of the major elements in different stages of the progressive metamorphic process are discussed according to mass balance equations. Finally, the quantitative analysis of the mass loss and volume loss of the different rocks the in Marinwobo fault is discussed in this paper.     

福建行洛坑钨矿床白钨矿Sm-Nd等时线年龄及微量元素地球化学特征

行洛坑超大型钨矿床位于福建省宁化县东部,是武夷山成矿带内最大的钨矿床,具有储量大、品位低、黑钨矿与白钨矿资源量相近的特点。白钨矿作为含钨矿物,其形成年龄可以代表矿床的成矿时代,其地球化学特征反映了成矿作用环境和过程。文章在对行洛坑钨矿床钨矿脉特征、黑钨矿与白钨矿赋存状态开展调查的基础上,挑选白钨矿单矿物进行了Sm-Nd等时线测年和微量元素测试。研究结果显示,白钨矿结晶年龄为（142.6±2.8）Ma,略小于黑钨矿原位U-Pb年龄（150.5±8.1）Ma和石英流体包裹体Rb-Sr等时线年龄（147.5±2.9）Ma,与矿区隐伏岩体成岩年龄143.5~149.5 Ma在误差范围内完全吻合,也与矿物结晶世代关系吻合,都属于晚侏罗世的产物,说明钨成矿与隐伏岩体成岩近于同时或稍晚发生。白钨矿中微量及稀土元素特征显示第一世代成矿流体中Eu³⁺ < < Eu²⁺,指示成矿流体为还原性流体;第二世代成矿流体中Eu³⁺ > > Eu²⁺,指示成矿流体为氧化性流体。行洛坑钨矿成矿与华南中生代大规模成矿作用及其大地构造背景和动力学环境密切相关。     

灰岩碳氧同位素特征与隐伏花岗岩的关系——以栗木水溪庙矿区为例

对栗木水溪庙矿区泥盆系上统融县组灰岩的碳氧同位素进行了研究,该地区灰岩的碳氧同位素组成可提供隐伏花岗岩隆起及其相关流体的重要信息。受隐伏花岗岩侵入驱动的流体与上覆融县组灰岩发生反应的温度在110℃左右,流体的初始同位素组成为δ18OSMOW=-3‰,δ13CPDB≤-7‰,反应的水岩比值（w/r）可能小于5。这种岩浆水与大气降水的混合流体与围岩之间的水岩反应使得地表灰岩的δ18O和δ13C值降低,产生负异常。研究表明,围岩的δ18O值降低受反应的水岩比值和温度控制;δ13C值降低主要与反应的水岩比值有关。反应的温度越高,w/r值越大,灰岩的碳氧同位素负异常越明显。因此,水溪庙矿区地表出露的碳酸盐地层中的碳氧同位素变化可在地球化学勘查中用于指示下伏花岗岩岩脊的隐伏位置。     

Evolution of Ore-Forming Fluids and Ag-Cu Polymetal Mineralization in the Lanping Basin, Yunnan

EVOLUTION OF ORE-FORMING FLUIDS AND Ag-Cu POLYMETAL MINERALIZATION IN THE LANPING BASIN, YUNNAN“KeyProjectforResourcesandEconomics” (95 0 2 0 0 1 0 1)oftheMinistryofLandResources     

Albite vein formation during exhumation of high-pressure terranes: a case study from alpine Corsica

The formation of late‐stage veins can yield valuable information about the movement and composition of fluids during uplift and exhumation of high‐pressure terranes. Albite veins are especially suited to this purpose because they are ubiquitously associated with the greenschist facies overprint in high‐pressure rocks. Albite veins in retrogressed metabasic rocks from high‐pressure ophiolitic units of Alpine Corsica (France) are nearly monomineralic, and have distinct alteration haloes composed of actinolite + epidote + chlorite + albite. Estimated P–T conditions of albite vein formation are 478 ± 31 °C and 0.37 ± 0.14 GPa. The P–T estimates and petrographic constraints indicate that the albite veins formed after the regional greenschist facies retrogression, in response to continued decompression and exhumation of the terrane. Stable isotope geochemistry of the albite veins, their associated alteration haloes and unaltered hostrocks indicates that the vein‐forming fluid was derived from the ophiolite units and probably from the metabasalts within each ophiolite slice. That the vein‐forming fluid was locally derived means that a viable source of fluid to form the veins was retained in the rocks during high‐pressure metamorphism, indicating that the rocks did not completely dehydrate. This conclusion is supported by the observation of abundant lawsonite at the highest metamorphic grades. Fluids were liberated during retrogression via decompression dehydration reactions such as those that break down hydrous high‐pressure minerals like lawsonite. Albite precipitation into veins is sensitive to the solubility and speciation of Al, which is more pressure sensitive than other factors which might influence albite vein formation such as silica saturation or Na:K fluid ratios. Hydraulic fracturing in response to fluid generation during decompression was probably the main mechanism of vein formation. The associated pressure decrease with fracturing and fluid decompression may also have been sufficient to change the solubility of Al and drive albite precipitation in fracture systems.     

SH波入射时多个半圆形沉积谷地附近浅埋圆形孔洞的动力分析

本文采用辅助函数的思想,利用复变函数和多级坐标的方法给出了SH波入射条件下多个半圆形沉积谷地附近浅埋圆形孔洞动力分析问题的解答。将整个求解区域分割成两部分来处理,区域I为多个半圆形沉积谷地,区域II为浅埋圆形孔洞附近带半圆形凹陷的半无限弹性空间。在区域I和II中分别构造位移解,并在二个区域的“公共边界”上实施位移应力的连续条件,建立求解该问题的无穷代数方程组。最后,本文给出了算例和数值结果,并对其进行了讨论。     

含水层中海水入侵的数学模型

提出了考虑过渡带的适合潜水含水层和承压含水层的海水入侵数学模型,导出了相应的方程和定解条件.经实例验证,模型是合理和可靠的.     

地下越流排污工程实例及应用前景——以贵阳市金关片区地下越流排污工程为例

以贵阳市金关片区地下越流排污工程为例，充分利用水环境功能差异和有利的自然地理条件，采取地下隧道工程，改变污水流向，以达到饮用水源保护与经济协调发展的目标。     

黔东南那哥铜、铅多金属矿床构造地球化学特征及矿质来源初探

那哥铜、铅多金属矿床构造控制明显,矿体产于近东西向的F2断层中;地层中成矿元素含量Cu等低,而构造破碎带内及那哥辉绿岩体Cu、Pb等含量高;地层、构造及岩体的As、Zn等含量基本相同;地层、构造、岩体微量元素对比及硫铅同位素显示,成矿元素可能来自深部幔源.综合研究认为其成因类型可能归为岩浆热液矿床,构造起到至关重要作用...