The tectonic evolution of the Ongole Domain, India: a metamorphic and geochronological approach

• Main Author: Henderson, B. J.
• Other Authors: School of Physical Sciences
• Format: Thesis
• Language: English
• Published: 2011
• Subjects: Honours; Geology; Ongole Domain; Eastern Ghats Belt; Nuna; zircon; monazite; pseudosections; Lu-Hf isotopes; rare earth elements; Ti-in-zircon thermometry; UHT metamorphism; East Antarctica; Napier; Antarc*; Antarctica
• Online Access: http://hdl.handle.net/2440/96173

This item is only available electronically. The Ongole Domain, situated in the southern Eastern Ghats Belt, exposes an assemblage of granulite facies metasedimentary and metaigneous rocks that preserve fundamental evidence for the Paleoproterozoic-Mesoproterozoic reconstruction of the supercontinent Nuna. LA-ICP-MS detrital zircon data from metasedimentary rocks constrain the timing of deposition for the sedimentary precursors, to between ca. 1850-1750 Ma. Lu-Hf isotopic data from detrital zircons provide a wide range of εHf values between -18 and +10, and TDM of ca. 3.2- 2.6 Ga. The Mesoarchean to Paleoproterozoic detrital components display geochemical similarities with the Napier Complex, the North Australian Craton and to a lesser extent, the North China Craton. U-Pb zircon and monazite geochronology have identified three episodes of metamorphism in the Ongole Domain; at ca. 1750, 1640 and 1590 Ma. Peak P-T estimates of 900 - 910°C and 9 - 9.2 kbar are calculated for metamorphism associated with collisional orogenesis, between ca. 1640-1590 Ma. Ti-in-zircon thermometry independently constrains the UHT conditions, yielding estimates of 935 ± 55°C. U-Pb geochronology and trace element analysis of zircon grains from metaigneous rocks confirm syn-tectonic magmatism occurred in the Ongole Domain between ca. 1640-1570 Ma. The results provide support for paleogeographic reconstructions that link the southern Eastern Ghats Belt and East Antarctica during the late Paleoproterozoic Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Earth and Environmental Sciences, 2011