The Dufek Intrusion is a mafic layered intrusion that was emplaced into present-day Antarctica approximately 183 million years ago. It comprises two outcropping sections called the Dufek Massif and the Forrestal Range that are thought to be connected beneath the

Sallee Snowfield Sallee Snowfield () is a large snowfield between the Dufek Massif and northern Forrestal Range in the Pensacola Mountains, Antarctica. Mapping and name The Sallee Snowfield was mapped by United States Geological Survey (USGS) from surveys and Uni ...

. The Dufek intrusion is associated with large volumes of Jurassic tholeiitic magmatism associated with the breakup of

Gondwana Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final stages ...

. This magmatism stretched from northern Victoria Land to Dronning Maud Land and onwards into Africa and Australia.

Stratigraphy Stratigraphy is a branch of geology concerned with the study of rock (geology), rock layers (Stratum, strata) and layering (stratification). It is primarily used in the study of sedimentary rock, sedimentary and layered volcanic rocks. Stratigrap ...

within the intrusion includes the 1.8 km thick Dufek Massif section and associated

nanatak Nunatak was the British Antarctic Survey’s (BAS) Rothera Research Station’s house band. The five person indie rock band was part of a science team investigating climate change and evolutionary biology on the Antarctic Peninsula. They are chief ...

s. This massif section is composed of the 230 m thick Walker Anorthosite, with laminated plagioclase cumulates, overlain by the Aughenbaugh Gabbro. This gabbro consists of laminated plagioclase with and the

augite Augite is a common rock-forming pyroxene mineral with formula . The crystals are monoclinic and prismatic. Augite has two prominent cleavages, meeting at angles near 90 degrees. Characteristics Augite is a solid solution in the pyroxene group. ...

- pigeonite

pyroxene The pyroxenes (commonly abbreviated to ''Px'') are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula , where X represents calcium (Ca), sodium (Na), iron (Fe II) ...

cumulus. The upper portion of the intrusion consists of the 1.7 km thick Forrestal Range section, with the Saratoga Gabbro cumulates overlain by the 300 m thick Lexington Granophyre.

References

Geology of Antarctica Layered intrusions {{Geology-stub