West Antarctic Rift System

The West Antarctic Rift System is a broad zone of fault-bounded basins beneath West Antarctica, formed as the continent stretched and thinned. Its buried structure helps explain the region’s low elevation, volcanism, and complex ice-sheet behavior.

Continental rifting: The stretching and thinning of continental lithosphere, often producing faults, basins, and eventual new oceanic crust. Extension across West Antarctica produced the system’s fault-bounded basins.
West Antarctica: The part of Antarctica lying mainly west of the Transantarctic Mountains, including the Antarctic Peninsula and Marie Byrd Land. The rift system underlies much of this tectonically complex region.
West Antarctic Ice Sheet: The marine-based ice sheet covering much of West Antarctica, grounded largely below sea level. Rift basins influence the bed beneath this vulnerable ice sheet.
Gondwana: An ancient supercontinent that joined most of today’s Southern Hemisphere continents. The rift developed as Antarctica’s position and tectonic setting changed during Gondwana’s breakup.
East Antarctic Craton: The ancient, relatively stable continental interior underlying much of East Antarctica. Its stability contrasts with the faulted, extended crust beneath West Antarctica.
Rift basin: A depression formed where the crust subsides between faults during tectonic extension. These buried basins make up the system’s principal structural units.
Lithosphere: Earth’s rigid outer shell, comprising the crust and the uppermost mantle. The system formed through deformation of this outer shell.
Subglacial topography: The shape and elevation of the land surface concealed beneath glacier ice. Mapping rift-related basins reveals the bed over which Antarctic ice flows.
Gondwana breakup: The fragmentation of Gondwana into separate continental plates during the Mesozoic and Cenozoic eras. Regional extension is part of the wider tectonic history surrounding the rift.
Transantarctic Mountains: A mountain range separating East Antarctica from West Antarctica and extending across the continent. The range marks a major boundary near the rift system’s eastern side.

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