Retrograde fluid evolution at the Rampura Agucha Pb-Zn-(Ag) deposit, Rajasthan, India

Abstract

Fluid inclusions in mineralized graphite-sillimanite-mica schist from the Rampura-Agucha Pb-Zn-(Ag) deposit, Rajasthan, northwest India, have been investigated by microthermometry and Raman microspectrometry. Three different main types of fluid inclusions in quartz can be distinguished: (1) gaseous (CO/, partially mixed with CH4-N2), (2) low salinity aqueous inclusions (0-8 eq. wt% NaC1) and (3) high salinity aqueous inclusions (NaCI _+ MgC12-CaC12). Low density CO2rich and low salinity H20 inclusions are contemporaneous and occur, together with CH4-N 2 inclusions, in close association with sulfide mineral inclusions. This indicates immiscibility between the gaseous and aqueous phase and participation of these fluids during the deposition or remobilization of the ore, which occurred over a wide P (1220 to 200 bar) and T (450 to 250 ~ Raman spectra of graphite indicate upper greenschist-facies metamorphic conditions, although host rocks have been metamorphosed at upper amphibolite-facies metamorphic conditions. This indicates that graphite re-equilibrated with the CO2-rich phase during retrograde metamorphism.

Metamorphism of the host and associated rocks at the Rajpura–Dariba massive sulfide deposit, Northwestern India

“…Similar inference has been made for the graphites in the Rampura-Agucha massive sulfide deposit in the Aravalli-Delhi belt (Fig. 1), based on Raman spectroscopic studies (Holler et al, 1996) that indicates the graphites had undergone granulite facies metamorphism (Mishra et al, 2002).…”

Correlations between the North China Craton and the Indian Shield: Constraints from regional metallogeny

“…The Bhilwara Supergroup hosts ZnPb-Ag ore mineralization (DaribaeRaipur) related to Proterozoic ensialic foldbelts. Stratiform Pb-Zn deposits are localized in the carbonate part of a section in the Aravalli Supergroup (Deb, 1986;Höller et al, 1996;Turchenko et al, 2009). A large number of Mn (BIF) (e.g., Sadanandrapur), graphite (e.g., Chintakonda), and superimposed muscovite pegmatite deposits (e.g., Sangam) occurred in the belt of the Proterozoic tectonothermal reworking of the Eastern Ghats, which is an important ore-bearing tectonic unit that bears indications of polycyclic collision (Turchenko et al, 2009).…”

Geochronology and fluid inclusion studies of the Lailisigaoer and Lamasu porphyry–skarn Cu–Mo deposits in Northwestern Tianshan, China

“…Roedder (1984) and Andersen and Burke (1996) considered that CH 4 can be produced by the reaction between hydrothermal fluid and carbonaceous country rock in situ or in the transfer process (Holler et al, 1996;Fig. 10.…”