赤峰地区金矿床流体包裹体与深部预测

对赤峰地区石英脉型及蚀变岩型(含石英脉蚀变岩)金矿床的研究表明,石英中流体包裹体的成分、温度和特征元素比值等可以作为金矿化找矿评价和深部预测的标志。(1) 石英中的流体包裹体,是成矿溶液的代表,反映了金矿形成的条件和环境。可以将均一温度作为一种深部预测的变量指标。(2) 石英红外光谱CO_2和H2_的光密度,实际上反映的是石英中流体包裹体CO_2和H_2O的含量特征。D_2和D_2/D_1的特征值可以作为金矿床深部预测的变量参数。从上到下,D_2/D_1值的增大,可以预示金矿化向下逐渐增强。(3) 容矿围岩为石墨片岩(或含有机质的岩层)的金矿床,包裹体的气体成分,特别是CH_4和N_2的含量与金的富集有关,可以判别“无矿”和“含金”石英。

FLUID INCLUSIONS AND DEEP PROGNOSIS OF GOLD DEPOSITS, CHIFENG, INNER MONGOLIA, CHINA

In the gold deposits, gold has a close relation with quartz and pyrite. Therefore, the following conclusions have been drawn upon deep prognosis of the gold deposits in the Chifeng district, Inner Mongolia on the basis of studies of fluid inclusions: (1) fluid inclusions bear much information about ore-forming fluids, and their forming conditions can be regarded as a variation index in deep prognosis; (2)the absorption intensities of CO_2 and H_2O, as observed in the infrared spectra of quartz, represent their contents in inclusions in quartz, so the ratio of CO_2/H_2O(D_2/D_1)can be taken as an indicator of deep mineralization; (3) certain amounts of volatiles in inclusions from the gold deposit hosted in graphite schist, especially CH_4 and N_2, may keep to distinguish auriferous quartz veins from non-auriferous ones.