Details

Autor(en) / Beteiligte

• Sengupta, Siladitya
• Basak, Krishnapriya

Titel

Mesoproterozoic orogeny along the eastern boundary of Aravalli Craton, northwestern India: A structural and geochronological study of Hindoli–Jahazpur Group of rocks

Ist Teil von

• Journal of Earth System Science, 2021-12, Vol.130 (4), p.203, Article 203

Ort / Verlag

New Delhi: Springer India

Erscheinungsjahr

2021

Link zum Volltext

Quelle

2022 ECC(Springer)

Beschreibungen/Notizen

• Two linear NE–SW trending belts of platformal orthoquartzite-carbonate sequence, namely, the East Jahazpur Belt (EJB) and the West Jahazpur Belt (WJB), within a vast tract of slate–argillite–metagreywacke and subordinate metavolcanics of Hindoli Group (HG) together occur sandwiched between Vindhyan sediments to the east and Banded Gneissic Complex-II (BGC-II) to the west, at the eastern boundary of Aravalli Craton, Rajasthan, India. A NE–SW trending crustal-scale transpressive shear separates this low-grade supracrustal sequence from the gneisses of older Mangalwar Complex (BGC-II) to the west and the Great Boundary Fault (GBF) restricts it in the east against the Vindhyan rocks. A lensoid body of strongly deformed and mylonitised Jahazpur Granite (JG), is the basement for the supracrustal rocks and occupies the core of a SE verging D 1 -antiformal nappe defined by the EJB (Jahazpur Group-I) rocks. This large scale D 1 thrust nappe structure in the EJB is manifested by stacking of early recumbent folds in the carbonate and quartzite units and a prominent zone of brecciation and ferruginisation all along the eastern margin of EJB. In the WJB (Jahazpur Group-II), D 1 is represented by large scale isoclinal reclined fold geometry, likely to be influenced by the major transpressive shear and refolding at its western margin. D 2 deformation phase, variably superposed over the D 1 structures, together controls the NE–SW disposition of Hindoli and Jahazpur rocks. Based on the structural patterns and lithostratigraphic characters, we propose a revised stratigraphy of the Hindoli–Jahazpur rocks. Whole rock Rb–Sr dating of the strongly deformed and mylonitised Jahazpur Granite constrained the age of the tectono-metamorphic event that affected these rocks. Two suites of mylonitised Jahazpur Granite from two different localities yielded ages of 1423 ± 52 and 1393 ± 33 Ma, using Sector 54 TIMS. The tectonism that resulted in folding, thrust nappe, shearing and mylonitisation involving basement JG of Neoarchean age and the overlying Paleoproterozoic Jahazpur–Hindoli supracrustal sequences, therefore, represents a Mesoproterozoic (~1.4 Ga) orogeny that is correlatable with the breaking-up of Columbian Supercontinent along the eastern margin of the Aravalli craton.