Neoarchaean crustal reworking in the Aravalli Craton: Petrogenesis and tectonometamorphic history of the Malola granite, Bhilwara area, northwestern India

Abstract

The Banded Gneissic Complex of the Aravalli Craton of northwestern India comprises Palaeo‐ to Neoarchaean (3.3–2.7 Ga) gneisses, including tonalite–trondhjemite–granodiorite (TTG) gneisses, intruded by Neoarchaean (2.6–2.5 Ga) TTGs, sanukitoids, and potassic granites. The latter include the Malola granite that crops out near Bhilwara and forms the basement for the Mesoproterozoic Pur‐Banera mineralized belt. The granite has experienced three deformation events, represented by an S1 foliation and superimposed open folds and dextral shears. Textural evidence and thermobarometry indicate that prograde metamorphism initially forming actinolite and subsequently diopside, and culminating in the upper amphibolite facies, was followed by retrograde metamorphism in the greenschist facies with fluid influx, forming zoisite. Zircon geochronology yields a crystallization age of 2,538 ± 11 Ma and indicates a prominent metamorphic overprint in the region at 1,307 ± 9 Ma. The Malola granite has low Sr–Nd isotopic ratios, enrichments in fluid‐mobile elements (Cs, Rb, Ba, Th, and Pb), and depletions in alteration‐resistant elements (Nb, Ta, and Ti). These characteristics combined with mineralogical evidence suggest that the granite was derived by anatexis of older crystalline crust (possibly granulitic lower crust) in the same subduction zone setting inferred previously for other Neoarchean granitoids in this region. Geochemical and Sr–Nd–Hf isotopic similarities between the Malola granite and Neoarchaean granitoids of the Aravalli, Bundelkhand, Bastar, Dharwar, and Congo cratons indicate a major role for anatectic crustal reworking in their genesis.

Metamorphic P–T–t–d evolution of the Mesoproterozoic Pur‐Banera supracrustal belt, Aravalli Craton, northwestern India: Insights from phase equilibria modelling and zircon–monazite geochronology of metapelites

“…Abundant asymmetrical crenulations in the metapelites and asymmetrical mica tails developed around garnet porphyroblasts suggest that the S 3 foliation is related to a dextral shearing event (Figure 3f). This inference is consistent with the development of a mylonitic fabric in the adjacent Malola granite (D'Souza et al, 2020), and the development of asymmetrical folds and oblique shape-preferred orientations of quartz grains in the associated quartzofeldspathic gneisses (D'Souza et al, 2019). These similarly oriented shear fabrics in the granite, gneisses and schists suggest a ~N-S-directed dextral-reverse shearing event in the PBB.…”

“…The Aravalli Craton in northwestern India (Figure 1a) has experienced several cycles of magmatism, sedimentation, deformation and metamorphism between c. 3.3 and 0.8 Ga (e.g. Bhowmik et al, 2010;Buick et al, 2010;Dey et al, 2019;D'Souza et al, 2019D'Souza et al, , 2020Gopalan et al, 1990;Roy & Kröner, 1996;Roy et al, 2005Roy et al, , 2012Wiedenbeck et al, 1996aWiedenbeck et al, , 1996b. The central and southern parts of the craton consist largely of Meso-to Neoarchaean (3.3-2.7 Ga) basement gneisses that are commonly referred to as the Banded Gneissic Complex (BGC; Figure 1b).…”

Ti‐in‐zircon and Ti‐in‐quartz thermometry using electron probe microanalysis: A promising approach in retrieving thermal conditions of granulite facies metamorphism and felsic magmatism in the Sandmata Complex, Aravalli Craton (NW India)

“…The samples investigated in this study were collected from an east–west traverse in the Sandmata Complex (Aravalli Craton; Figure 1a,b) that is tectonically juxtaposed with Palaeoproterozoic Aravalli Supergroup to the east and Palaeo‐ to Neoproterozoic Delhi Supergroup to the west (D'Souza et al, 2019; D'Souza et al, 2020; Ghosh et al, 2022; Roy & Jakhar, 2002). The eastern and central parts of the Sandmata Complex are composed of medium‐grade banded gneisses, including grey granite gneisses, composite gneisses and pelitic gneisses (Gupta, 1934; Heron, 1953; Naha & Roy, 1983; Roy et al, 2005; Roy & Jakhar, 2002; Sharma, 1994).…”

Rift‐related multistage evolution of the Mangalwar Complex, Aravalli Craton (NW India): Evidence from elemental and Sr–Nd isotopic features of Proterozoic amphibolites

“…In contrast to the BGC‐I, the BGC‐II terrane of the central Rajasthan is composed of diverse lithounits that were formed during the Archean Eon and largely reworked during the Proterozoic (I. Ahmad, Mondal, Bhutani, & Satyanarayanan, 2018; Bhowmik & Dasgupta, 2012; Dharma Rao et al, 2011; Kaur, Zeh, & Chaudhri, 2021; Roy & Jakhar, 2002). Fascinatingly, the gneisses of the Mangalwar Complex of the BGC‐II also exhibit Paleoarchean to Neoarchean lineage (I. Ahmad, Mondal, Bhutani, & Satyanarayanan, 2018; D'Souza et al, 2020; D'Souza, Prabhakar, Xu, Sharma, & Sheth, 2019; Dey et al, 2019; Dharma Rao et al, 2011; Roy, Kröner, Rathore, Laul, & Purohit, 2012). S. N. Gupta et al (1980) and Guha and Bhattacharya (1995) based on metamorphic grade and rock association, have further characterized the BGC‐II into two distinct lithotectonic domains namely, the Sandmata Complex of granulite facies (supracrustal rocks along with metaigneous granulites and intrusive megacrystic orthopyroxene‐bearing granitoids) and the Mangalwar Complex metamorphosed up to amphibolite facies (basement gneisses, granitoids, migmatitic/para‐gneisses, amphibolites and metasedimentary lithounits).…”