The nature of the Grenville-age charnockitic A-type magmatism from the Natal, Namaqua and Maud Belts of southern Africa and western Dronning Maud Land, Antarctica

• Main Authors: Grantham,G.H., Eglington,B.M., Thomas, R.J., Mendonidis, P.
• Format: Report
• Language: English
• Published: Council for Geoscience/Council for Geoscience/Council for Geoscience/Department of Metallurgy, Vaal Triangle Technikon 2001
• Subjects: charnockite; A-type; Natal; Namaqualand; Dronning Maud Land; Antarc*; Antarctica; Memoirs of National Institute of Polar Research; Polar Research
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=2414; http://id.nii.ac.jp/1291/00002414/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=2414&item_no=1&attribute_id=18&file_no=1

The ∿1030-1090Ma old, locally charnockitic, intrusions which are exposed from Namaqualand in the west, through Natal, into the Maud Province Antarctica in the east, show A-type, within plate granite characteristics. The major and trace element characteristics from all the intrusions are remarkably similar and consistent and are typical of C-Type charnockites. Two-pyroxene thermometry as well as thermometry utilising calibrations from experimental studies of saturation surfaces using Zr, P and Ti suggest temperatures between ∿850℃ and ∿1100℃. Pressure estimates from aureole assemblages suggest depths of emplacement between 30-10km. Available isotopic data suggest magma sources in Natal and Antarctica were juvenile, probably mantle derived whereas those in Namaqualand suggest a significant crustal contribution.