A series of northeast-trending mountain ranges, with a rock-surface relief of more than 2500 metres, projects through an ice mantle that is in places 1500 metres thick to form the rock massifs and nunataks of western Dronning Maud Land. The oldest rocks found in these ranges belong to a metamorphic complex that probably underlies much of this part of Antarctica. Unconformably overlying the metamorphic complex is an assemblage of flat-lying, clastic sediments; this in turn locally includes, or is overlain by, volcanic rocks. The sediments have been intimately invaded by large sills and dykes of diorite and gabbro. The youngest known rocks are small basaltdykes.
Since the metamorphism of the basement complex, the area has been essentially stable, and has suffered only minor, vertical movements.