Structure and tectonics of a Mesoproterozoic ophiolite – Insight from Kanigiri Ophiolite with a mélange zone, southern India

Sain, Arnab; Saha, Dilip

doi:10.1016/j.tecto.2018.06.017

Cited by 11 publications

(1 citation statement)

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“…There is a sort of trend of emplacement age of plutons ending towards the south. Sain & Saha (2018) have opined that the 1284 Ma Kanigiri granite intruded the 1334 Ma Kanigiri Ophiolite and thus affirmed their post-tectonic emplacement. In line with the above argument, the studied PG with age 1257 ± 6 Ma is so far the youngest member of felsic plutons in NSB, formed and emplaced in an extensional environment.…”

Section: D Age Constraintsmentioning

confidence: 99%

Geochemistry and new zircon U–Pb geochronology of Mesoproterozoic Punugodu granite pluton, SE India: implications for anorogenic magmatism along the western margin of Nellore Schist Belt, India

et al. 2022

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We report a new zircon U–Pb age of 1257 ± 6 Ma for the Punugodu granite (PG) pluton in the Eastern Dharwar Craton (EDC), Southern India. The Mesoproterozoic PG is alkali feldspar hypersolvus granite emplaced at shallow crustal level, as evident from the presence of rhyodacite xenoliths and hornfelsic texture developed in the metavolcanic country rocks of the Neoarchaean Nellore Schist Belt (NSB). Geochemically, the PG is metaluminous, ferroan and alkali-calcic, and is characterized by high SiO2 and Na2O + K2O, Ga/Al ratios >2.6, high-field-strength elements and rare earth element (REE) contents with low CaO, MgO and Sr, indicating its similarity to anorogenic, alkali (A-type) granite. The highly fractionated REE patterns with negative europium anomalies of PG reflect its evolved nature and feldspar fractionation. Mafic (MME) to hybrid (HME) microgranular enclaves represent distinct batches of mantle-derived magmas that interacted, mingled and undercooled within the partly crystalline PG host magma. Felsic microgranular enclaves (FME) having similar mineralogical and geochemical characteristics to the host PG most likely represent fragments of marginal rock facies of the PG pluton. The PG appears to be formed from an oceanic island basalt (OIB)-like source in an anorogenic, within-plate setting. The emplacement of PG (c. 1257 Ma) in the vicinity of Mesoproterozoic Kanigiri Ophiolite (c. 1334 Ma) shows an age gap of nearly 77 Ma, which probably suggests PG emplacement in an extensional environment along a terrain boundary at the western margin of the Neoarchaean NSB in the EDC.

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Section: D Age Constraintsmentioning

confidence: 99%