Brown Bluff is a tuya

Tuya

A tuya is a type of distinctive, flat-topped, steep-sided volcano formed when lava erupts through a thick glacier or ice sheet. They are somewhat rare worldwide, being confined to regions which were covered by glaciers and also had active volcanism during the same time period.-Formation:Tuyas are...

 located at the northern tip of the Antarctic Peninsula

Antarctic Peninsula

The Antarctic Peninsula is the northernmost part of the mainland of Antarctica. It extends from a line between Cape Adams and a point on the mainland south of Eklund Islands....

, Antarctica. It formed in the past 1 million years, which erupted subglacially within an englacial lake. The volcano's original diameter is thought to have been about 12-15 kilometers, and probably formed by a single vent. Brown Bluff is subdivided into four stages: pillow volcano, tuff cone, slope failure, and hyaloclastite delta and into five structural units.

The volcano is named "Brown Bluff" because of its steep slopes and its brown-to-black hyaloclastite

Hyaloclastite

Hyaloclastite is a hydrated tuff-like breccia rich in black volcanic glass, formed during volcanic eruptions under water, under ice or where subaerial flows reach the sea or other bodies of water. It has the appearance of angular flat fragments sized between a millimeter to few centimeters...

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Topography

Brown Bluff has a 1.5 km long cobble and [ash] beach rising increasingly steeply towards towering red-brown tuff [cliffs] which are embedded with volcanic bombs. The cliffs are heavily eroded, resulting in loose scree and rock falls on higher slopes and large, wind eroded boulders on the beach. At high water the beach area can be restricted. Permanent ice and tidewater glaciers surround the site to the north and south occasionally filling the beach with brash ice.

Fauna

Confirmed breeders: gentoo penguin (Pygoscelis papua), Adélie penguin (Pygoscelis adeliae), pintado petrel (Daption capense), snow petrel (Pagodroma nivea), skua (Catharacta, spp.) and kelp gull (Larus dominicanus). Suspected breeders: southern giant petrel (Macronectes iganteus) southern fulmar (Fulmarus glacialoides) and Wilson’s storm-petrel (Oceanites oceanicus). Regularly haul out: Weddell seals (Leptonychotes weddellii). Leopard seals (Hydrurga leptonyx) often hunt offshore.

Flora

Xanthoria, spp. and Caloplaca, spp. observed on exposed boulders from shoreline to an elevation of 185m. Some moss, spp. exposed at higher elevations near glacial drainage.