Geology of the Vardeklettane Terrane, Heimefrontfjella (East Antarctica)

Abstract: In the southwest of the Heimefrontfjella mountain range a granulite- facies terrane is exposed in the small Vardeklettane nunataks. The Vardeklettane Terrane extends, however, at least 65 km farther WNW to the nunatak group of Mannefallknausane, where comparable granulites are exposed. The terrane is composed of mafic and felsic granulites, leucogranite orthogneiss and metasedimentary rocks. The maximum deposition age of the latter is constrained by detrital zircon U-Pb data ranging from 2000 to 1200 Ma whereas the leucogranite gneiss gave a late Mesoproterozoic crystallization age of 1135 Ma. The Vardeklettane Terrane is unique as being the only part of the otherwise juvenile Late Mesoproterozoic basement of Heimefrontfjella to have a Paleoproterozoic crustal component. Structurally, the terrane is separated from the main range by the Heimefront Shear Zone.