Abstract Gaussberg is a nunatak composed of lamproite pillow lava situated on the coast of East Antarctica. It is the most isolated Quaternary volcanic centre in Antarctica but it is important palaeoenvironmentally and petrologically out of all proportion to its small size. The edifice has a likely low, shield-like, morphology c. 1200 m high and possibly up to 10 km wide, which is unusually large for a lamproite construct. Gaussberg was erupted subglacially at 56 ± 5 ka, which places it late in the last glacial, close to the peak of marine isotope stage 3. The coeval ice sheet was c. 1300 m thick, and c. 420 m has been removed from the ice surface since Gaussberg erupted. Lamproite is a rare ultrapotassic mantle-derived magma, and Gaussberg is one of two type examples worldwide. Although traditionally considered as related in some way to the Kerguelen plume, it is more likely that the Gaussberg magma is a product of a separate magmatic event. It is ascribed to the storage and long-term (Gy) isolation of sediment emplaced by subduction in the Transition Zone of the deep mantle, followed by entrainment and subsequent melting in a plume.

The particle size and provenance signature of glacial till from the Lonewolf Nunataks at the head of Byrd Glacier, Antarctica, show evidence of subglacial origin and therefore provide new information about ice-covered bedrock of East Antarctica. Particle-size data from ice-cored moraines at Lonewolf Nunataks show more abundant silt and clay (>50% fines) than active lateral moraines along downstream sites (<10% fines), and 25% of pebbles are faceted and/or striated. Sand and pebbles from moraines at Lonewolf Nunataks are a mix of locally derived Beacon Supergroup rocks and exotic felsic igneous and metamorphic rocks. The U/Pb detrital zircon data from the Lonewolf Nunataks till show significant populations of zircon ages, including early Ross and/or Pan-African ages of ca. 565–610 Ma, Grenville ages (ca. 950–1270 Ma), several Proterozoic peaks, and one prominent late Archean peak at ca. 2700 Ma. 40 Ar/ 39 Ar analyses of detrital hornblende and mica also show Ross and/or Pan-African ages from ca. 500 to 580 Ma, with a population of Grenville-age hornblende grains of ca. 1150–1250 Ma. This combination of geochronological tools can be used to identify recycled versus primary age populations eroded by the ice sheet, and so provide constraints on the age and distribution of unmapped, ice-covered bedrock. Our data show that petrologic and geochronologic signatures in East Antarctic till can be used to address geologic problems ranging from Cenozoic ice sheet history to Precambrian bedrock geology.