During the Late Precambrian the basement of the southern belt was unconformably overlain by marine sediments of the Watts Needles Formation, the age of which is constrained by stromatolites and acritarchs (Golanov ., 1980; Weber, 1991).
The history of the northern belt of the Shackleton Range, which is exposed from east to west in the Pioneers Escarpment, the Herbert Mountains, La Grange Nunataks and the Haskard Highlands (Fig.
, (1)Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, 2020-2207 Main Mall, Vancouver, BC V6T 1Z4, Canada, (2)Institut für Mineralogie, Westfälische Wilhelms-Universität, Corrensstraße 24, Münster, 48149, Germany, [email protected] The geological interpretation of petrological processes depends on our ability to accurately and precisely place these in a tectonic timeline.
Accessory minerals are most commonly used in chronology.
Petrological indicators for a polymetamorphic evolution could be reflected by an abrupt change of the garnet growth zonation, garnet resorption patterns prior to a new garnet overgrowth, or the orientation of mineral inclusions.The basement of the southern belt predominantly consists of Proterozoic ortho- and paragneisses of the Read Group, which underwent high-grade amphibolite- to granulite-facies metamorphism (Schubert & Will, 1994; Talarico & Kroner, 1999).Proterozoic metamorphism and cooling is indicated by a Rb–Sr whole-rock isochron age of 1763 ± 32 Ma from a granitic orthogneiss (Pankhurst ., 1983).In this paper, we present a detailed petrological study combined with geochronological results obtained from metapelitic rocks from the northeastern part of the Shackleton Range (Fig. Inset: position of the Shackleton Range in Antarctica. (b) Block diagrams showing the geological situations at Lord and Meade nunataks.The Shackleton Range is formed from two east-trending mountain belts, situated at 80–81°S (Fig. The southern belt is exposed in the Read Mountains and at Stephenson Bastion, and forms part of the East Antarctic Craton.Nevertheless, interpreting the resulting dates in terms of petrological processes is typically non-trivial.