The northern Prince Charles Mountains consist largely of layered and massive granulite to upper amphibolite facies intruded by charnokite plutons, granite, and pegmatite veins, and alkaline igneous dykes. The southern Prince Charles Mountains have Archean granitic orthogneiss basement overlain by Archean quartzites that are intruded by pegmatites and tholeiitic dykes. These Archean rocks are overlain by Proterozoic greenschist facies metasediments, including conglomerates, sandstone, schists, and phyllites that are intruded by Cambrian granite. Phanerozoic Sediments Geophysical data indicate that the Lambert Graben and Prydz Bay Basin contain several kilometers of sediment. These sediments are thought to be present within the Lambert Graben as well.
Cenozoic sediments are also present in the Prince Charles Mountains.
In the northern Prince Charles Mountains at Beaver Lake some 800 m of diamictons and minor mudstone and sandstone is exposed in Pagodroma Gorge. Smaller outcrops of Proterozoic gneisses and Cambrian granites are scattered along the eastern coast south of the largest area of outcrop in the Vestfold Hills. The red bed sequence consists of sandstone interbedded with claystone and siltstone that may reach a thickness of 2-3 km in the center of the Prydz Bay Basin. The sediments are brown red to green gray in color. Sandstone units are as thick as 3 m and are medium to coarse grained, fining up to siltstone and claystone.