Dissolution channels in quartz and the role of pressure changes in gold and sulfide deposition in the Archean, greenstone-hosted, Hutti gold deposit, Karnataka, India

Carbon isotope studies of auriferous quartz carbonate veins from two orogenic gold deposits from the Neoarchean Chitradurga schist belt, Dharwar craton, India: Evidence for mantle/magmatic source of auriferous fluid

“…The present study on C and O isotopic composition of carbonates of QCVs from the same area, reinforces magmatic origin for the fluids. As mentioned earlier, apart from Ajjanahalli, such type of mantle or subcrustal source of ore fluids has been inferred for Kolar gold deposits by Santosh (1992) and Hutti gold deposits by Pandalai et al (2003) (see Table 1). Mantle and/or magmatic origin of gold mineralizing fluids seems to be widespread in the Dharwar craton.…”

“…Santosh et al (1995) attributed similar origin of fluids for the Wynaad Gold deposits located in granulites. Pandalai et al (2003) based on C and O isotopic composition of fluid inclusions also suggested subcrustal origin of fluids for the Hutti gold deposits. Kolb et al (2004) based on silicate oxygen isotopic study of Ajjanahalli deposit found that d 18 O H 2 O is suggestive of magmatic/mantle origin.…”

“…Undulose extinction, deformation lamellae and ribbon structures in auriferous QCVs indicate their syntectonic emplacement. Opinions on the source of auriferous ore fluids for the gold deposits of Dharwar craton vary from metamorphic devolatilization (Ananta Iyer and Vasudev, 1979;Pal and Mishra, 2004) to mantle (Santosh, 1992;Pandalai et al, 2003) and magmatic (Narayanaswamy et al, 1960) sources. In this paper, we present new C and O isotopic data on carbonates of auriferous QCVs from two gold deposits viz, Ajjanahalli and Guddadarangavvanahalli (G.R.…”

Pb, Sr and Nd isotope systematics of metavolcanic rocks of the Hutti greenstone belt, Eastern Dharwar craton: Constraints on age, duration of volcanism and evolution of mantle sources during Late Archean

“…Petrographic study of the metabasalts has shown that they have been subjected up to lower amphibolite facies metamorphism and the metabasalts from the N-S arm had undergone low-temperature alteration which has resulted in extensive chloritization of ferromagnesian minerals. Shearing of these rocks might have facilitated entry of hydrothermal fluids resulting in precipitation of quartz-carbonate veins some hosting gold mineralization (Pal and Mishra, 2002;Pandalai et al, 2003;Kolb et al, 2004Kolb et al, , 2005Mishra et al, 2005). The scatter of the samples in the isotope evolution diagram (Fig.…”

“…Giritharan and Rajamani, 1998;Pal and Mishra, 2002;Pandalai et al, 2003;Rogers et al, 2007;Srinivasa Sarma et al, 2008;Manikyamba et al, 2009). This paper presents the findings of Rb-Sr, Sm-Nd and Pb-Pb isotope study on the metavolcanic rocks of the Hutti greenstone belt and integrates with the results of the earlier geochronological studies to decipher the age and duration of formation of volcanic rocks of the belt and to better understand crust-mantle evolution in the eastern Dharwar craton.…”