Publication Date:
2008-11-24
Description:
Rb-Sr and Sm-Nd mineral dating of metamorphic rocks from Skallen, Skallevikshalsen and Rundvagshetta, in the southwestern part of the Lutzow-Holm Complex, Dronning Maud Land, assists in constructing a thermal history after peak metamorphism. The results fall into two groups: (1) a record of regional cooling after peak metamorphism (524-488 Ma); (2) local resetting 50-80 Ma after peak metamorphism (474-446 Ma). This grouping is consistently observed in published ages from various localities in the Lutzow-Holm Complex. A Sm-Nd age of 524 Ma is indistinguishable from published zircon and monazite ages. Ages of 511 and 488 Ma are related to cooling after peak metamorphism. The younger age group overlaps with ages of post-metamorphic magmatism and related hydrothermal activity reported from localities throughout East Antarctica. This intracontinental, post-orogenic igneous activity continued after the tectonic assembly of Gondwana.