EPMA monazite geochronology of the basement and supracrustal rocks within the Pur-Banera basin, Rajasthan: Evidence of Columbia breakup in Northwestern India. (1st March 2016)

• Record Type: Journal Article
• Authors: Ozha, Manoj Kumar; Mishra, Biswajit; Hazarika, Pranjit; Jeyagopal, A.V.; Yadav, G.S.
• Is Part Of: Journal of Asian earth sciences. Volume 117(2016)
• Page Start: 284
• Page End: 303
• Publication Date: 2016-03-01
• Subjects: Aravalli–Delhi Fold Belt -- Monazite EPMA dating -- Polyorogeny -- Columbia breakup -- Rajasthan; Earth sciences -- Asia -- Periodicals; Sciences de la terre -- Asie -- Périodiques; Earth sciences; Asia; Periodicals; 555.05
• DOI: 10.1016/j.jseaes.2015.12.016
• Languages: English
• ISSNs: 1367-9120

Abstract

Highlights: Mangalwar complex (MC) underwent a mid-amphibolite peak metamorphism at ∼1.82 Ga. MC and Pur-Banera (PB) witnessed upper amphibolite peak metamorphism at 1.37–1.35 Ga. Grenvillian high pressure overprinting in both MC and PB rocks at 1.05–0.99 Ga. Episodic garnet growth for a period of ∼0.84 Ga in the MC. Evidence of Columbia and Rodinia supercontinent cycles. Abstract: We deduce the timing of the rift-induced collisional event between two orogenies in the central Aravalli–Delhi Fold Belt using monazite chemical dating and metamorphic P – T estimates from metapelites of the Mangalwar Complex (MC), and the overlying Pur-Banera (PB) supracrustals. The MC rocks preserve evidence of three regional metamorphic events, while the PB rocks record the last event. The M1 metamorphism attained its peak P – T at ∼5.5 kbar and 520–550 °C in the MC rocks at ∼1.82 Ga, followed by the M2 event with peak P – T of ∼7.5 kbar and 580–660 °C at ∼1.35 Ga. The youngest high-pressure M3 metamorphism attained a peak P – T of ∼8.0 kbar and 590–640 °C at ∼0.99 Ga. Thermobarometry coupled with ages of included monazites in chemically zoned garnet from the MC metapelites indicate preservation of ages spanning between ∼1.82 Ga and ∼0.99 Ga from different zones (i.e., core to rim), implying episodic garnet growth during supercontinent cycle. The PB metapelites constitute two prominent ages of ∼1.37 Ga and ∼1.05 Ga. The youngest high-pressure metamorphism (M3 ) in the PB rocks with maximum P – T of ∼8.0 kbar, and 580–670 °C during the Neoproterozoic has overprinted their earlier metamorphic records. Based on monazite geochronology, we assign the ∼1.82 Ga and ∼1.37–1.35 Ga ages to the amalgamation and breakup of the Columbia supercontinent respectively. The youngest age record of ∼1.05–0.99 Ga indicates evidence of Rodinia formation in and around the Pur-Banera basin.