T11 Vapors, Brines, Sulfides, and Mines: Understanding Metal Mobility in Magma-Hydrothermal Systems and Their Supergene Successors

Sunday, 31 October 2010
8:00 AM - 12:00 PM
Room 601

MICROBIAL CONTROLS ON ORE WEATHERING AND METAL ION MOBILITY

Paper number: T11-15
Program: Technical Sessions
Time: 11:45 AM – 12:00 PM

Authors

Abstract

The influence of microorganisms in near-surface geologic settings has been found to extend to redox processes, mineral formation and dissolution, degradation of organic compounds, and metal fate and transport. Recent investigations have expanded the knowledge of deep terrestrial microbial ecology, geochemical controls on microbial diversity and microbial influence on weathering and geochemical cycling [1, 2]. We investigated a unique biofilm community located at 1.4km depth, in the Triple 7 Cu/Zn mine (Flin Flon, Canada). Isolates of a neutrophilic, halophilic Marinobacter spp. were obtained, capable of organotrophic growth (anaerobically and aerobically), and lithotrophic growth on Fe(II). Therefore, we examined the possibility that Fe(II) oxidation could be an important biogeochemical pathway contributing to ore oxidation and weathering in the deep subsurface [3, 4].

We examined ore weathering and metal ion mobility in the deep subsurface using incubation experiments with ore types from Triple 7 and the Fe(II)-oxidizing Marinobacter isolate in both batch and column flow-through settings. The activity of the Marinobacter isolate resulted in an increase in the mobilization of Fe, S and trace metals (Cu, Zn) from all materials. These results indicate that microbial activity, specifically Fe(II) oxidation in the deep subsurface, affects the weathering and oxidation of buried sulphides and subsequent metal mobility.

[1] MacLean et al. (2007) Geomicrobiol J 24, 491-504. [2] Sahl et al. (2008) Appl. Environ. Microbiol. 74, 143-152. [3] Leslie et al. (2010) Geochimica et Cosmochimica Act 74, A583. [4] Swanner et al. (2010) Geochimica et Cosmochimica Act 74, A1013.