Rainbow Ridge is a small ridge which forms a distinct western rim to the large crater-like depression high in the central part of Brown Peninsula

Brown Peninsula

Brown Peninsula is a nearly ice-free peninsula, long and wide, which rises above the Ross Ice Shelf northward of Mount Discovery, to which it is connected by a low isthmus. It was discovered by the British National Antarctic Expedition, 1901–04, which named it "Brown Island" because of its color...

, in Victoria Land

Victoria Land

Victoria Land is a region of Antarctica bounded on the east by the Ross Ice Shelf and the Ross Sea and on the west by Oates Land and Wilkes Land. It was discovered by Captain James Clark Ross in January 1841 and named after the UK's Queen Victoria...

. Given this geologically descriptive name by the New Zealand Antarctic Place-Names Committee

New Zealand Antarctic Place-Names Committee

New Zealand Antarctic Place-Names Committee is an adjudicating committee established to authorize the naming of features in the Ross Dependency on the Antarctic continent. It is composed of the members of the New Zealand Geographic Board plus selected specialists on Antarctica...

 (NZ-APC), it arose from investigations by the New Zealand Geological Survey and the Victoria University Expedition in 1964-65. The top of the ridge has been planed off by subsequent glaciation and the resultant surface exposes two basalt "pipes" (Nubian Formation) within the trachyte. These have altered the trachyte at their margins to various shades of brown, hence the name of the ridge.