A cryptic Gondwana-forming orogen located in Antarctica

• Published in: Scientific Reports
• Main Authors: Daczko, NR, Halpin, JA, Fitzsimons, ICW, Whittaker, JM
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Publishing Group 2018
• Subjects: Antarctica; plate reconstruction; Gondwana; Antarctic; East Antarctica; Indian; Mirny; Antarc*
• Online Access: https://eprints.utas.edu.au/27250/; https://eprints.utas.edu.au/27250/1/Daczko%2B%2BGondwanaAntarctica_SciRep_2018.pdf

The most poorly exposed and least understood Gondwana-forming orogen lies largely hidden beneathice in East Antarctica. Called the Kuunga orogen, its interpolation between scattered outcrops isspeculative with differing and often contradictory trends proposed, and no consensus on the locationof any sutures. While some discount a suture altogether, paleomagnetic data from Indo-Antarcticaand Australo-Antarctica do require 3000–5000 km relative displacement during Ediacaran-CambrianGondwana amalgamation, suggesting that the Kuunga orogen sutured provinces of broadly Indianversus Australian affinity. Here we use compiled data from detrital zircons offshore of East Antarcticathat fingerprint two coastal subglacial basement provinces between 60 and 130°E, one of Indian affinitywith dominant ca. 980–900 Ma ages (Indo-Antarctica) and one of Australian affinity with dominant ca.1190–1140 and ca. 1560 Ma ages (Australo-Antarctica). We combine this offshore compilation withexisting and new onshore U-Pb geochronology and previous geophysical interpretations to delimit theIndo-Australo-Antarctic boundary at a prominent geophysical lineament which intersects the coast eastof Mirny at ~94°E.