Glacial beds:

An early Permian (?) tillite sequence is exposed on the western side of the Lanterman Range, north of the Orr Glacier (McKelvey, 1982). The tillite is faulted against the metamorphic rocks of the Wilson Group and is tightly folded. The following description is from McKelvey and Walker (1982).

The glacial beds are of acid plutonic and metasedimentary provenance and are exposed on two spurs about 2 kilometres apart. On the northern spur the oldest exposed strata consist of at least 70 metres of poorly sorted lensoidal or channel-fill outwash conglomerates, pebbly sandstones and diamictites associated with laminated or cross-bedded coarse sandstones. The coarser rock types are most common at the top and bottom of this interval. A dark mudstone and shale unit containing interbeds of thin sandstone, lensoidal conglomerate and a fine diamictite overlies. This unit thickens eastwards to at least 150 metres and changes rapidly in fades to a monotonous mudstone sequence containing in its uppermost 80 metres thin laterally persistent graded and laminated turbidites sometimes with erosional bases and containing infraformational sandstone clasts. No dropstones are present. More than 100 metres of coarse outwash strata similar to those at the base of the section overlie.

On the southern spur a similar coarse sandstone sequence with lensoidal conglomerates and pebbly sandstones at the base overlies more than 150 metres of fissile or massive mudstones alternating with very coarse tillite sheets and lenses. Most of the mudstone and shale horizons contain sparsely scattered dropstones.

The contact between the folded glacigene sequence in the Lanterman Range and the widespread Permian fluvial Takrouna Formation of northern Victoria Land has not been observed. Coarse metasediment breccias up to 50 metres thick and associated sometimes with minor petromict conglomerate lenses frequently mantle the pre-Permian basement complex beneath the Takrouna Formation. No definite glacial features have been observed in these breccias.