Fluid inclusion, geochemical, Rb–Sr and Sm–Nd isotope studies on tungsten mineralized Degana and Balda granites of the Aravalli craton, NW India

Abstract

Granitic plutons occurring within and to the west of the Delhi Fold Belt in the Aravalli craton, northwestern India are the result of widespread felsic magmatism during Neoproterozoic, some of which are associated with greisen and skarn tungsten deposits. In this paper, we present the result of our study on fluid inclusions, geochemistry and geochronology of two such tungsten mineralized granite plutons at Degana and Balda, and interpret the nature of ore fluid, and petrogenesis and age of these mineralized granites. Fluid inclusion study reveals coexistence of moderate and hyper-saline aqueous fluid inclusions along with aqueous-carbonic inclusions, suggesting their origin due to liquid immiscibility during fluid-rock interaction. Geochemically, the granites are peraluminous, Rb enriched, Sr and Ba depleted and highly differentiated. The Rb-Sr isotopic systematics yielded 795 ± 11 Ma for Balda granite and 827 ± 8 Ma for Degana granite. We show that major phase of widespread granitoid magmatism and mineralization during the Neoproterozoic (840-790 Ma) in NW India is coeval with breakup of the Rodinia supercontinent and infer a causal relationship between them.

Tracing source and palaeo‐weathering conditions of quartzose sandstone in the Cretaceous Cambay Basin: A combined petrographical, geochemical and geochronological approach

“…The composition of approximately 50% of the schorl and dravite types of tourmaline grains in Himmatnagar Sandstone matches with tourmaline of the Sewariya‐Govindgarh and Balda‐Motiya granites. Additionally, the ages of the Sewariya‐Govindgarh and Balda‐Motiya granites (Table 5) are similar to the 906 Ma peaks of monazite grains, further supporting the idea that both tourmaline and monazites in the Himmatnagar Sandstone are derived from the South Delhi Supergroup of rocks (Figure 8a; see also Ghosh et al, 2021; Just et al, 2011; Sivasubramaniam et al, 2019; S. Singh et al, 2021; Vijay Anand et al, 2018). Other 650–1000 Ma ages of monazite grains match with the rocks listed in Table 5, showing their derivation from the South Delhi Supergroup of rocks in the ADFB.…”

“…Prominent highlands in these areas include ADFB, Deodar Ridge and Devikot High (Figure 12). Accordingly, The Pan-African orogeny-related rocks are poorly exposed in the western and northwestern part of India (Ashwal et al, 2013;Crawford, 1975;Islam et al, 1999;Rathore et al, 1999;Xu et al, 2022; 8a; see also Ghosh et al, 2021;Just et al, 2011;Sivasubramaniam et al, 2019;Vijay Anand et al, 2018). Other 650-1000 Ma ages of monazite grains match with the rocks listed in Kaur et al, 2021) of the ADFBs (Table 5).…”