Lomonosov Ridge – an underwater ridge in the Arctic Ocean. It separates the bottom into two parts, distinct from one another: Atlantic in the west (Eurasian subbasin) and Pacific in the east (Amerasian subbasin). This ridge is a large underwater blocky and block-folded structure rising from the ocean floor for more than 2,000 m. It stretches for approximately 1,800 km from the New Siberian Islands through the central part of the ocean to the Ellesmere Island in the Canadian Arctic Archipelago. The ridge is 950–1,650 m deep, is 60–200 km wide, and has a rounded crest; it rises above the surrounding areas of the ocean floor for around 3,000–3,700 m. The minimum depth over the individual peaks is above 900 m. The crest of the ridge is 26 km wide; it is mainly flat, indicating that it was truncated to a depth of 1,400 m below sea level. The slopes are relatively steep, dissected with canyons, and covered with deposits of silt and sandy silt.
The ridge was discovered in 1948 by Soviet high-latitude expeditions, which became one of the largest geographical discoveries of the twentieth century. It was named after M.V. Lomonosov.
In the 2000s, the geological structure of the ridge attracted the international attention due to a claim submitted by Russia to the UN Commission on the Limits of the Continental Shelf. In this document the Russian side argued a proposal to establish new outer limits for the Russian continental shelf, beyond the previous 200-nautical-mile zone (but within the Russian Arctic sector). One of the arguments was the statement that the underwater Lomonosov Ridge and Mendeleyev Ridge are extensions of the Eurasian continent. In 2002 the UN Commission neither rejected nor accepted the Russian proposal, recommending additional research. In 2007 the Russian expedition worked in the aquatorium of the ridge to specify the limits of the continental shelf. A set of studies was conducted that year, including deep seismic studies, above-ice gravity measurements, airborne geophysical survey, acoustic measurements, telephotometry shooting, and bottom sampling. The preliminary results of an analysis of the earth crust model examined by “The Arctic-2007” Expedition gave the Ministry of Natural Resources of Russian Federation reasons to believe that the structure of this ridge corresponds to the world analogs of the continental crust, and it is therefore part of the Russian Federation’s adjacent continental shelf. Since 2004 Denmark also intensified its research of the bottom of the Arctic Ocean and the northern part of the Atlantic Ocean. One of the goals is to prove that the L.R. is an extension of Greenland. In December 2013 Canada also submitted a claim to the UN Commission to extend the continental shelf.