Palaeomagnetism of a stratiform intrusion in the Pensacola Mountains, Antarctica

A LARGE stratiform mass of pyroxene gabbro interlayered with smaller amounts of anorthosite and pyroxenite and capped with granophyre makes up most of the northern ranges of the Pensacola Mountains (Fig. 1)¹. These layered rocks are at least 2,000 m thick in both the Dufek Massif and the Forrestal Range, and are believed to belong to a single sheet-like body with an areal extent of at least 8,000 km². The age of the body is not known with certainty, but it intrudes folded rocks as young as Permian (personal communication from J. M. Schopf) and therefore is probably Mesozoic or younger.