Brown Bluff is a basalt tuya on the Tabarin Peninsula of northern Antarctica. It formed in the last 1 million years as a result of subglacial eruptions within an englacial lake. The volcano's original diameter is thought to have been about and probably formed by a single vent. Brown Bluff is divided into four stages: pillow volcano, tuff cone, slope failure, and hyaloclastite delta; and into five structural units.