通过对湖南沃溪Au-Sb-W矿床鱼儿山-红岩溪矿段中黑钨矿族矿物的野外观察表明，含黑钨矿族矿物的矿石主要呈条带状、细脉状，次为浸染状构造，结构上主要为半自形-它形板状和柱状；X射线粉晶衍射结果得出其物相为钨铁矿，晶胞参数为a0：4...通过对湖南沃溪Au-Sb-W矿床鱼儿山-红岩溪矿段中黑钨矿族矿物的野外观察表明，含黑钨矿族矿物的矿石主要呈条带状、细脉状，次为浸染状构造，结构上主要为半自形-它形板状和柱状；X射线粉晶衍射结果得出其物相为钨铁矿，晶胞参数为a0：4.7454 A ，b0：5.7160A ，c0：4.9753 A ，β：90°13′；电子探针分析结果显示，MnO含量范围0.97%-11%，FeO含量范围13.65%-23.36%，WO3含量范围71.39%-76.87%，既有高MnO含量亦有低MnO含量的钨铁矿，成连续性变化，并从深部中段向浅部中段，MnO含量具有增大趋势。计算其晶体化学式为（Fe0.57-1.02Mn0.46-0.04）W0.98-1.00O4。相关分析得出FeO与MnO相关系数为-0.98，WO3与MnO相关系数为0.47，WO3与FeO相关系数为-4.10。黑钨矿族矿物中Nb和Ta的含量较低，暗示了沃溪Au-Sb-W矿床可能为沉积-改造热液成因。展开更多
Scheelite Sm-Nd and quartz Ar-Ar dating were accomplished for the Woxi Au-Sb-W deposit in western hu-nan. The results show that the Sm and Nd concentrations of scheelite are relatively high, and Sm/Nd ratios are usual...Scheelite Sm-Nd and quartz Ar-Ar dating were accomplished for the Woxi Au-Sb-W deposit in western hu-nan. The results show that the Sm and Nd concentrations of scheelite are relatively high, and Sm/Nd ratios are usually high and variable. In the 147Sm/144Nd vs. 143Nd/144Nd diagram, the disseminated scheelites show a good linear array, which corresponds to an isochron age of 402 6 Ma and an initial 143Nd/144Nd ratio of 0.510544 9 (2s ) with a e Nd(t) value of -30.7. The Ar-Ar age spectra for 2 quartz samples display the saddle shape. The minimum apparent age, plateau age and isochron age of each quartz sample generally overlap within errors; and both the minimum apparent ages of 420 20 and 414 19 Ma coincide well with the scheelite Sm-Nd age. Both Sm-Nd and Ar-Ar dating results reveal that the Au-Sb-W mineralization at Woxi district took place in the Late Caledonian. This is in good agreement with the tectonic evolution of the Xuefengshan district and with some geo-chronological data available for Au, Sb and W deposits in this area. The low initial Nd isotope ratio of scheelites sug-gests that the fluid responsible for Au-Sb-W mineralization at the Woxi is of deep crustal origin and probably originated from the underlying Archaean continental basement rather than the host Proterozoic strata in western Hunan. The con-straints on the mineralization time and on the fluid source provide insight into the genesis of the Woxi deposit.展开更多
文摘通过对湖南沃溪Au-Sb-W矿床鱼儿山-红岩溪矿段中黑钨矿族矿物的野外观察表明，含黑钨矿族矿物的矿石主要呈条带状、细脉状，次为浸染状构造，结构上主要为半自形-它形板状和柱状；X射线粉晶衍射结果得出其物相为钨铁矿，晶胞参数为a0：4.7454 A ，b0：5.7160A ，c0：4.9753 A ，β：90°13′；电子探针分析结果显示，MnO含量范围0.97%-11%，FeO含量范围13.65%-23.36%，WO3含量范围71.39%-76.87%，既有高MnO含量亦有低MnO含量的钨铁矿，成连续性变化，并从深部中段向浅部中段，MnO含量具有增大趋势。计算其晶体化学式为（Fe0.57-1.02Mn0.46-0.04）W0.98-1.00O4。相关分析得出FeO与MnO相关系数为-0.98，WO3与MnO相关系数为0.47，WO3与FeO相关系数为-4.10。黑钨矿族矿物中Nb和Ta的含量较低，暗示了沃溪Au-Sb-W矿床可能为沉积-改造热液成因。
基金supported by the National Key Basic Research Program(Grant No.G1999043200)the National Natural Science Foundation for Outstanding Youth(Grant No.49925309)the Knowledge Innovation Research Program from the Chinese Academy of Sciences(Grant No.KZCX3-SW-125).
文摘Scheelite Sm-Nd and quartz Ar-Ar dating were accomplished for the Woxi Au-Sb-W deposit in western hu-nan. The results show that the Sm and Nd concentrations of scheelite are relatively high, and Sm/Nd ratios are usually high and variable. In the 147Sm/144Nd vs. 143Nd/144Nd diagram, the disseminated scheelites show a good linear array, which corresponds to an isochron age of 402 6 Ma and an initial 143Nd/144Nd ratio of 0.510544 9 (2s ) with a e Nd(t) value of -30.7. The Ar-Ar age spectra for 2 quartz samples display the saddle shape. The minimum apparent age, plateau age and isochron age of each quartz sample generally overlap within errors; and both the minimum apparent ages of 420 20 and 414 19 Ma coincide well with the scheelite Sm-Nd age. Both Sm-Nd and Ar-Ar dating results reveal that the Au-Sb-W mineralization at Woxi district took place in the Late Caledonian. This is in good agreement with the tectonic evolution of the Xuefengshan district and with some geo-chronological data available for Au, Sb and W deposits in this area. The low initial Nd isotope ratio of scheelites sug-gests that the fluid responsible for Au-Sb-W mineralization at the Woxi is of deep crustal origin and probably originated from the underlying Archaean continental basement rather than the host Proterozoic strata in western Hunan. The con-straints on the mineralization time and on the fluid source provide insight into the genesis of the Woxi deposit.
