Interaction of coeval felsic and mafic magmas from the Kanker granite, Pithora region, Bastar Craton, Central India

Abstract

Field and petrographic studies are carried out to characterize the interactions of mafic and felsic magmas from Pithora region of the northeastern part of the Bastar Craton. The MMEs, syn-plutonic mafic dykes, cuspate contacts, magmatic flow textures, mingling and hybridization suggest the coeval emplacement of end member magmas. Petrographic evidences such as disequilibrium assemblages, resorption textures, quartz ocelli, rapakivi and poikilitic textures suggest magma mingling and mixing phenomena. Such features of mingling and mixing of the felsic and mafic magma manifest the magma chamber processes. Introduction of mafic magmas into the felsic magmas before initiation of crystallization of the latter, results in hybrid magmas under the influence of thermal and chemical exchange. The mechanical exchange occurs between the coexisting magmas due to viscosity contrast, if the mafic magma enters slightly later into the magma chamber, then the felsic magma starts to crystallize. Blobs of mafic magma form as MMEs in the felsic magma and they scatter throughout the pluton due to convection. At a later stage, if mafic magma enters the system after partial crystallization of felsic phase, mechanical interaction between the magmas leads to the formation of fragmented dyke or syn-plutonic mafic dyke. All these features are well-documented in the study area. Field and petrographic evidences suggest that the textural variations from Pithora region of Bastar Craton are the outcome of magma mingling, mixing and hybridization processes.

Magma chamber processes and geodynamic implications of the Pithora pluton, Bastar Craton, Central India

“…In plutonic environment, the homogenisation and heterogenisation features are well-documented in the form of ME, syn-plutonic mafic dyke, hybrid enclaves, and flow structures. These features are reported from different parts of the Bastar Craton Pal, 2004a and2004b;Kumar & Rino, 2006;Pandit & Panigrahi, 2012;Elangovan, Krishna, Vishwakarma, Hari, & Ram Mohan, 2017). MEs are also reported in postcollisional granitoids from Mahakoshal belt (Bora, Kumar, Yi, Kim, & Lee, 2013) and related to Pan-African Orogeny in south Khasi Hills of Meghalaya Plateau (Kumar & Pieru, 2010;Kumar, Pieru, Rino, & Hayasaka, 2017;Kumar, Pieru, Rino, & Lyngdoh, 2005).…”

“…These features are reported from different parts of the Bastar Craton (Kumar, Rino, & Pal, and 2004b; Kumar & Rino, ; Pandit & Panigrahi, ; Elangovan, Krishna, Vishwakarma, Hari, & Ram Mohan, ). MEs are also reported in postcollisional granitoids from Mahakoshal belt (Bora, Kumar, Yi, Kim, & Lee, ) and related to Pan‐African Orogeny in south Khasi Hills of Meghalaya Plateau (Kumar & Pieru, ; Kumar, Pieru, Rino, & Hayasaka, ; Kumar, Pieru, Rino, & Lyngdoh, ).…”

“…Typology of granitoids and the field evidence of mingling and mixing of felsic and mafic magmas were studied from the Malanjkhand granite (Kumar et al, 2004a;Kumar, Rino, & Pal, 2004b). Based on field observations and textural features, Elangovan et al (2017) has studied the morphological and petrological characteristics of granitoids from the Pithora region and associated syn-plutonic mafic dykes. This FIGURE 1 (a) Geological map of Bastar Craton (after Mohanty, 2015); (b) Detailed geological map of Pithora region from Bastar Craton (modified after Mathur, 2004).…”

“…This FIGURE 1 (a) Geological map of Bastar Craton (after Mohanty, 2015); (b) Detailed geological map of Pithora region from Bastar Craton (modified after Mathur, 2004). [Colour figure can be viewed at wileyonlinelibrary.com] contribution is an extension to that of Elangovan et al, 2017, wherein, with additional tools, the petrogenetic mechanism and tectonic setting of Pithora pluton are constrained with regional geodynamic implications.…”

“…Typology of granitoids and the field evidence of mingling and mixing of felsic and mafic magmas were studied from the Malanjkhand granite (Kumar et al, ; Kumar, Rino, & Pal, ). Based on field observations and textural features, Elangovan et al () has studied the morphological and petrological characteristics of granitoids from the Pithora region and associated syn‐plutonic mafic dykes. This contribution is an extension to that of Elangovan et al, , wherein, with additional tools, the petrogenetic mechanism and tectonic setting of Pithora pluton are constrained with regional geodynamic implications.…”