Chattopadhyay, A (2000) Remobilization and concentration of gold in banded iron formation from Ajjenahalli area, Tumkur District, Karnataka, India. Journal of Metallurgy and materials Science, 42 (1). pp. 53-64.
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Banded Iron Formation (BIF), metavolcanics and metasediments constitute the major litho-units involved into complex deformation. BIF comprises of alternating bands of darker consituents (iron formation such as hematite, magnetite and geoethite) with lighter constituents (Silicates, such as, chert and quartz) and carbonate (Siderite and ankerite). Sulfide minerals are disseminated throughout the BIF, particularly it is more common in oxide and carbonate parts of BIF. Quartz veins that occur both along and acrose the banding are important regarding the sulfide mineralization. The same is true for the calcite vein. BIF is intrically folded and the closure of the folding, particularly antiformal closure is the enriched zone. The effect of brecciation is pronounced in quartz vein and some parts of BIF. Petrographic studies reveal that the BIF has undergone epigenetic and structurally-controlled metasomatism involving oxidation, carbonatization and sulfidation which accompany gold mineralization. XRF and XRD data indicate higher gold content in carbonate and quartz fraction than in the sulfide minerals. This suggests that a CO2-rich ore-fluid might have played an important role on gold mineraqlization. Two possible mechanisums for the concentration of gold have been discussed with reference to Ajjenhalli (latitude 13o45'-13o50'N and longitude 76o40'-76o45'E), India.
|Uncontrolled Keywords:||Banded iron formation; Remobilization; Concentration; Ajjenahalli; Gold|
|Deposited By:||Sahu A K|
|Deposited On:||16 Aug 2010 09:18|
|Last Modified:||23 Apr 2012 12:52|
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