SHRIMP U-Pb zircon data from Gjelsvikfjella, Dronning Maud Land, East Antarctica

• Main Authors: Bisnath, Avinash, Frimmel, Hartwig E, Armstrong, Robert A, Board, W S
• Format: Dataset
• Language: English
• Published: PANGAEA 2006
• Subjects: Dronning Maud Land; Antarctica; Gjelsvikfjella; Priority Programme 1158 Antarctic Research with Comparable Investigations in Arctic Sea Ice Areas; ROCK; Rock sample; SPP1158; Antarctic; Arctic; East Antarctica; Antarc*; Sea ice
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.847015; https://doi.org/10.1594/PANGAEA.847015

The Maud Belt in Dronning Maud Land (western East Antarctic Craton) preserves a high-grade polyphase tectono-thermal history with two orogenic episodes of Mesoproterozoic (1.2-1.0 Ga) and Neoproterozoic (0.6-0.5 Ga) age. New SHRIMP U-Pb zircon data from southern Gjelsvikfjella in the northeastern part of the belt make it possible to differentiate between a series of magmatic and metamorphic events. The oldest event recorded is the formation of an extensive 1140-1130 Ma volcanic arc. This was followed by 1104 ± 8 Ma granitoids that might represent, together with so far undated mafic dykes, part of a decompression melting-related bimodal suite that reflects the sub-continental Umkondo igneous event. The first high-grade metamorphism is constrained at 1070 Ma. The metamorphic age data are similar to those obtained from other parts of the Maud Belt, but also from the Namaqua-Natal Belt in South Africa, but the preceding arc formation was diachronous in the two belts. This indicates that the two belts did not form a continuous volcanic arc unit as suggested in previous models, but became connected only at the end of the Mesoproterozoic. Intense reworking during the Neoproterozoic, probably as a result of continent-continent collision between components of Gondwana, is indicated by ductile refliation, further high-grade metamorphic recrystallisation and metamorphic zircon overgrowths at approximately 530 Ma. This was followed by late- to post-tectonic magmatism, reflected by 500 Ma granite bodies and 490 Ma aplite dykes as well as a 480 Ma gabbro body.