The Ediacarian-Cambrian uplift history of western Dronning Maud Land: New Ar-40-Ar-39 and Sr/Nd data from Sverdrupfjella and Kirwanveggan, the source of the Urfjell Group and tectonic evolution of Dronning Maud Land within the Kuunga Orogeny and Gondwana amalgamation

摘要

Biotite Ar-40/Ar-39 ages from Mesoproterozoic gneisses from Kirwanveggan and Sverdrupfjella vary between 868-497 Ma and 547-326 Ma respectively. Hornblende ages from Kirwanveggan and Sverdrupfjella gneisses vary between 1067-480 Ma and 550-450 Ma respectively. The similar ages for hornblende and biotite from Sverdruptjella are consistent with rapid uplift in a single event. The differences in ages between biotite and hornblende from Kirwanveggan imply differential heating southwards through Kirwanveggan and suggest heating over northern Kirwanveggan at similar to 500 Ma with central to southern Kirwanveggan preserving older Mesoproterozoic Ar-40/Ar-39 ages in hornblende. The heating is inferred to result from burial in the footwall of a nappe.