Multiple shallow level sill intrusions coupled with hydromagmatic explosive eruptions marked the initial phase of Ferrar large igneous province magmatism in northern Victoria Land, Antarctica

Field data gathered during GANOVEX IX (2005/2006) in Northern Victoria Land, Antarctica, indicate that
volcaniclastic deposits of phreatomagmatic eruptions (so-called Exposure Hill Type events) are intercalated with fluvial
deposits of Triassic-Jurassic age at two stratigraphic levels. Abundant scoriaceous spatter (locally welded) indicates a
hawaiian/strombolian component. Breccia-filled diatremes, from which volcaniclastic deposits were sourced, are rooted
in sills which intruded wet sediments. The deposits are thus subaerial expressions of initial Ferrar magmatism involving
intrusion of multiple shallow-level sills. Due to magma-sediment interaction abundant clastic dikes are developed that
intrude the sediments and sills. All igneous components in the volcaniclastic deposits are andesitic in composition, as
are the chilled margins of the sills. They are more differentiated than the basaltic andesites of the younger effusive
section of Kirkpatrick plateau lavas which in northern Victoria Land start with pillow lavas and small volume lava
flows from volcanic necks.