云南省富乐铅锌多金属矿床闪锌矿中分散元素地球化学特征

GEOCHEMICAL CHARACTER OF DISPERSED ELEMENT IN SPHALERITE FROM FULE Pb-Zn POLYMETAL DEPOSIT,YUNNAN PROVINCE

分散元素广泛应用于高新技术领域,具有重要的经济价值,但因其在地壳中的低含量和其本身地球化学性质的分散性而不易富集成矿,但是富乐铅锌矿床中却有4种分散元素Cd,Se,G e,G a具有工业价值。该矿床位于我国重要的川滇黔多金属成矿带南东部,分散元素主要赋存在闪锌矿中,平均w(B)/10-6分别为Cd 16 183,Se 163,G e 135,G a 86,其中w(Cd)是迄今国内最高。闪锌矿分棕黑色、红棕色和黄棕色3种颜色。Cd在深色闪锌矿中而G e和G a在浅色闪锌矿中相对富集,Se在不同颜色闪锌矿中含量几乎不变。Cd,G e,Se主要呈类质同象形式存在,Cd,G e占据Zn的位置,而Se占据S的位置。G a主要以显微吸附形式存在,少量以类质同象形式存在。Zn与Cd负相关,而与G e正相关,与Se不相关。分散元素地球化学特征指示矿床为沉积-改造成因。

The dispersed elements have great economic value,and are widely applied to high and new-technology industries. However it is difficult for them to accumulate and form ore deposits because of their low assay and dispersivity in the crust. Four dispersed elements Cd ,Se ,Ge and Ga have economic value in Fule Pb Zn deposit which is localed in the southeast part of Sichan-Yunnan-Guihzou polymetallogenic district. The dispersed elements mainly occurred in sphalerites with average content of w（Cd） 16 183×10^-6,w（Se） 163×10^-6,w（Ge） 135×10^-6 and w（Ga） 86×10^-6 resectively,and with the content of Cd being the highest in China. The colour of sphalerite can be divided into dark-brown,red-brown and yellow-brown. Cd occurs mostly in dark colour sphalerite,Ge and Ga in light colour one,the content of Se does not change in different colour sphalerife. Mainly occurred as allomerism form,Cd,Ge,and Se occur in crystal lattice of sphalerite, where Cd and Ge occupy the position of Zn and Se occupies the position of S. Ga usually are adsorbed in lattice defect as micro-adsorption form,and the other enter sphalerite crystal lattice in place of Zn in sphalerite Cd-Zn are negative correlation,Ge Zn are positive correlations,but Se-Zn are independent. The geochemical characters of the dispersed elements indicate that the deposit belongs to sedimentation-reformation type.