四川松潘东北寨金矿预富集过程中的菌藻成矿作用

THE MINERALIZATION OF BACTERIA AND ALGAE IN THE PRE-ENRICHMENT OF DONGBEIZHAI GOLD DEPOSIT,SONGPAN,SICHUAN PROVINCE

Geological field work and laboratory simulation experiments have demonstrated that bacteria and algae contributed to the pre-enrichment of Dongbeizhai Gold Deposit. The algae flourished in the Songpan basin absorbed from sea water large amount of gold, the concentration of which increased by a few times through contemporaneous submarine vol-canisrn. The bacteria transfered gold from the algae buried in sediments into framboid pyrite and clay mineral through decomposing organic matter derived from algae. Theoretical calculation gives an estimation that biomineralization alone contributed about 27% gold of the orebody, thus algae and bacteria provided a considerable portion of gold in the source bed, which enriched to form ore deposit during hydrothermal metallogenesis in the later stages.