Geologic constraints on the existence and distribution of West Antarctic subglacial volcanism

Strong and abundant magnetic anomalies imaged beneath the West Antarctic Ice Sheet by aerogeophysical surveys have been interpreted as evidence of widespread Late Cenozoic basaltic volcanism, perhaps even a large igneous province. Petrological and geochemical composition of subglacial sediment samples from West Antarctica supports crustal provenance and does not provide positive evidence for the existence of the proposed mafic Late Cenozoic large igneous province. The only two identified basaltic pebbles, out of a total of >500 examined pebbles, are of Mesozoic to Cambrian age. We conjecture that the subglacial large igneous province does not exist or is blanketed by an at least Miocene age sedimentary drape.