The Geomicrobiology of Ore Deposits

Southam, Gordon; Saunders, James A.

doi:10.2113/gsecongeo.100.6.1067

Cited by 156 publications

(50 citation statements)

References 230 publications

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“…In this model, gold is derived from underlying geologic sources, e.g., the hydrothermal deposits, where it is present in its free metallic state or associated with sulfide minerals, such as pyrite and arsenopyrite. In arid, surficial environments (down to 500 m below the land surface; [75]) chemolithoautotrophic iron-and sulfur-oxidizing bacteria, e.g., A. ferrooxidans and A. thiooxidans, and archaea, are known to form biofilms on metal sulfides (e.g., gold-bearing pyrites and arsenopyrites), and obtain metabolic energy by oxidizing these minerals [3,76]. During this process thiosulfate is produced, which in the presence of oxygen leads to gold oxidation and complexation [77].…”

Section: Geobiological Formation Of Gold Anomalous Calcretementioning

confidence: 99%

Geobiological Cycling of Gold: From Fundamental Process Understanding to Exploration Solutions

et al. 2013

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Microbial communities mediating gold cycling occur on gold grains from (sub)-tropical, (semi)-arid, temperate and subarctic environments. The majority of identified species comprising these biofilms are β-Proteobacteria. Some bacteria, e.g., Cupriavidus metallidurans, Delftia acidovorans and Salmonella typhimurium, have developed biochemical responses to deal with highly toxic gold complexes. These include gold specific sensing and efflux, co-utilization of resistance mechanisms for other metals, and excretion of gold-complex-reducing siderophores that ultimately catalyze the biomineralization of nano-particulate, spheroidal and/or bacteriomorphic gold. In turn, the toxicity of gold complexes fosters the development of specialized biofilms on gold grains, and hence the cycling of gold in surface environments. This was not reported on isoferroplatinum grains under most near-surface environments, due to the lower toxicity of mobile platinum complexes. The discovery of gold-specific microbial responses can now drive the development of geobiological exploration tools, e.g., gold bioindicators and biosensors. Bioindicators employ genetic markers from soils and groundwaters to provide information about gold mineralization processes, while biosensors will allow in-field analyses of gold concentrations in complex sampling media.

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Section: Geobiological Formation Of Gold Anomalous Calcretementioning

confidence: 99%

Geobiological Cycling of Gold: From Fundamental Process Understanding to Exploration Solutions

et al. 2013

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“…icroorganisms are paramount for metal cycling and mineral formation in Earth surface environments (1)(2)(3). Metal cycles are driven by microorganisms, because some metal ions are essential for microbial nutrition, others are oxidized or reduced to obtain metabolic energy, while in particular heavy metal ions, e.g., Hg 2ϩ , Cd 2ϩ , Ag ϩ , Co 2ϩ , CrO 4 2 , Cu 2ϩ , Ni 2ϩ , Pb 2ϩ , Zn 2ϩ , also cause toxic effects (4).…”

mentioning

confidence: 99%

Mechanisms of gold biomineralization in the bacterium Cupriavidus metallidurans

Reith

Etschmann

Große

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

295

274

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“…at the contact of the Nissi (Patitira) bauxite laterites and the carbonate basement (Table 2; [16]) appears to create the appropriate conditions for iron and REE leaching and re-deposition [20,33,[49][50][51][52][53][54][55]. The preferential occurrence of REE-minerals in the lower transitional zone and within the underlain limestone (Figure 7) itself suggests that their formation was controlled by physico-chemical conditions, such as an alkaline barrier, redox potential, solubility, supersaturation [29,56] rather than by the precursor rocks.…”

Section: On the Origin Of Ree Fluorocarbonate Mineralsmentioning

confidence: 99%

On the Origin of Bastnaesite-(La,Nd,Y) in the Nissi (Patitira) Bauxite Laterite Deposit, Lokris, Greece

et al. 2017

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A detailed geochemical study and a thorough mineralogical description of the rare-earth elements (REE)-minerals and associated minerals were carried out in two vertical profiles of approximately 4 m length, from the Nissi (Patitira) bauxite laterite deposit, Lokris, Greece, characterized by the presence of goethite in small sizes resembling bacterial cell coated by goethite and a significant REE enrichment. The enrichment of the REE concentrated in bastnaesite-group minerals, the intergrowths between REE-minerals and Al-Ni-silicates with significant sulfur contents and their association with goethite microtextures interpreted as bacteriomorphic, indicate REE remobilization along with iron bio-leaching and re-precipitation on karstified limestone. In addition to the previous-reported hydroxylbastnaesites, a (La,Nd,Y)(CO 3 )F member of the bastnaesite-group associated with Al-Ni-silicates were identified, the stability of which may reflect the dependence on the source rocks and the local variations of pH-Eh. Interaction between downward percolating water and carbonate rocks seems to be a very effective mechanism for REE fluorocarbonates deposition under alkaline and reducing conditions.

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The Geomicrobiology of Ore Deposits

Cited by 156 publications

References 230 publications

Geobiological Cycling of Gold: From Fundamental Process Understanding to Exploration Solutions

Geobiological Cycling of Gold: From Fundamental Process Understanding to Exploration Solutions

Mechanisms of gold biomineralization in the bacterium Cupriavidus metallidurans

On the Origin of Bastnaesite-(La,Nd,Y) in the Nissi (Patitira) Bauxite Laterite Deposit, Lokris, Greece

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