The Dufek and Forrestal intrusions, Antarctica: A centre for Ferrar Large Igneous Province dike emplacement?

Abstract

Newly acquired aeromagnetic data indicate the presence of a dike swarm that may have acted as a magma transport and feeder system from the plume impact site up to 3,500 km to the Ferrar Large Igneous Province (FLIP). The Dufek and Forrestal intrusions, cover approximately 6,600 km2, and may form a ponding station between a mantle superplume responsible for Gondwana breakup and the FLIP sills and lavas along the Transantarctic Mountains into Tasmania and New Zealand. Prior to this survey, no feeder dike swarms or sills connecting with the Ferrar have been found in the Pensacola Mountains. Similarities with the Mackenzie dikes and intrusions of Northwest Canada imply that Jurassic dikes may have been emplaced into the pre‐existing Ross orogeny trend during doming above a mantle plume. However, our survey area is too small to show the dikes convincingly radiating from a focal point that would indicate the plume position.