关键词: 自然秘, 自然银, 矿物学

Abstract:

The Dulong Sn-Zn polymetallic deposit is one of China's three large cassiterite sulfide deposits, which occurs in the outer contact zones of the later Yanshan Laojunshan Granites. Ore minerals such as ferrosphalerite, cassiterite, pyrrhotite, pyrite and chalcopyrite，were formed in intermediate and high temperatures. Native bismuth and native silver, two kinds of native element minerals, have been discovered recently in this deposit. Their mineralogical features have been studied with an optical microscope, BSE, X-Ray scan, EDS and Laser-Raman spectrum. Both of native bismuth and native silver, most as irregularly shape fine grains occurred in inner and fine pores of sulfide minerals, have high purity with greater than 90%, which co-exist with chalcopyrite and galena, etc. Based on these studies mentioned above, it was suggested that there might be multi-stages during the magmatic hydrothermal mineralization, and native bismuth and native silver might formed in the last stage with low-middle temperatures and poor sulfur condition. This study also suggested that there might find the Ag-Bi mineralization on the outside of the skarn Zn-Sn mineralization.

Key words: native bismuth, native silver, mineralogy