Bennett Island (Russian: Остров Бе́ннетта, tr. Ostrov Bennetta; Yakut: Беннетт Aрыыта, romanized: Bennett Arııta) is the largest of the De Long Islands in the northern part of the East Siberian Sea. The area of this island is approximately 150 square kilometres (58 square miles) and it has a tombolo at its eastern end. The highest point of the island is 426 metres (1,398 feet) high Mount De Long, the highest point of the archipelago. Bennett Island is part of the Yakutia administrative division of Russia.

Bennett Island was discovered by the wider world by US explorer George W. De Long in 1881, and named after James Gordon Bennett Jr., who had financed the expedition. De Long set out in 1879 aboard the USS Jeannette, hoping to reach Wrangel Island and to discover open seas in the Arctic Ocean near the North Pole. However, the ship entered an ice pack near Herald Island in September 1879, and became trapped. The vessel was crushed by the ice and sank in June 1881. At that point the party was forced to trek over the ice on foot, discovering Bennett Island during July 1881, and claiming it for the United States. They remained on the island for several days before setting out again for the New Siberian Islands and the mainland of Siberia.^[1][2]

In August 1901, Russian polar ship Zarya sailed on an expedition searching for the legendary Sannikov Land but was soon blocked by floating pack ice. During 1902 the attempts to reach Sannikov Land continued while Zarya was trapped in fast ice. Russian explorer Baron Eduard Toll and three companions vanished forever in November 1902 while travelling away from Bennett Island towards the south on loose ice floes.^[3]

In 1916, the Russian ambassador in London issued an official notice to the effect that the Imperial government considered Bennett, along with other Arctic islands, integral parts of the Russian Empire. This territorial claim was later maintained by the Soviet Union.

Some individuals assert American ownership of Bennett Island, and others of the De Long group, based on the 1881 landing. However, the United States government has never claimed Bennett Island, and recognizes it as Russian territory.^[4]

Bennett Island consists of Early Paleozoic, late Cretaceous, Pliocene, and Quaternary sedimentary and igneous rocks. The oldest rocks outcropping on Bennett island are moderately tilted marine Cambrian to Ordovician sedimentary rocks. They consist of an approximately 500-metre (1,600 ft) thick sequence of argillites with minor amounts of siltstone, and limestone that contain Middle Cambrian trilobites and 1,000 to 1,200 metres (3,300 to 3,900 ft) of Ordovician argillites, siltstones, and quartz sandstones that contain graptolites. These Paleozoic rocks are overlain by Late Cretacecous coal-bearing argillites and quartzite-like sandstones and basaltic lava and tuff with lenses of tuffaceous argillite. The Late Cretaceous strata is overlain by basaltic lavas ranging in age from Pliocene to Quaternary. The Quaternary volcanic rocks form volcanic cones.^[5][6][7]

Little has been published about the climatology of Bennett Island in the English language literature. Dr. Glazovskiy^[8] stated that the annual precipitation on Bennett Island varied from 100 millimetres (3.9 in) at sea level to 400 millimetres (16 in) at the crest of the Tollya Ice Cap.

Bennett Island has the largest permanent ice cover within the De Long Islands. In 1987, the permanent ice cap of this island consisted of four separate glaciers that had a total area of 65.87 square kilometres (25.43 sq mi). All of these glaciers were perched on high, basaltic plateaus bounded by steep scarp-like slopes.^[9]

In 1992, Dr. Verkulich and others^[9] named these glaciers as the De Long East, De Long West, Malyy, and Toll glaciers. With an area of 55.5 square kilometres (21.4 sq mi) in 1987, Toll Glacier was the largest of them. It occupied the center of Bennett Island; had an elevation of 380 to 390 metres (1,250 to 1,280 ft) above mean sea level; and was 160 to 170 metres (520 to 560 ft) thick at its center. It had an outlet glacier, West Seeberg Glacier, from which ice flowed downhill from Toll Glacier into the sea. The next largest glacier was De Long East Glacier with an area of 5.16 square kilometres (1.99 sq mi) in 1987. It laid about 420 metres (1,380 ft) above mean sea level at the southeast end of Bennett Island and had a thickness of 40 to 45 metres (131 to 148 ft). Adjacent to De Long East Glacier laid the De Long West Glacier with an area of 1.17 square kilometres (0.45 sq mi); an elevation of 330 to 340 metres (1,080 to 1,120 ft) above mean sea level; and a thickness of 40 metres (130 ft) in 1987. Malyy Glacier, with an area of 4.04 square kilometres (1.56 sq mi) in 1987, occupied a basaltic plateau at an elevation of 140 to 160 metres (460 to 520 ft) above mean sea level on the northeast end of Bennett Island and was 40 to 50 metres (130 to 160 ft) thick. In 1987, all of these glaciers were shrinking in volume and had been so for the past 40 years.^[9]

Of the glaciers described by Dr. Verkulich and others,^[9] Dr. Glazovskiy^[8] discusses only the Toll Ice Cap, which Dr. Verkulich and others^[9] referred to as "Toll Glacier". In 1996, it had an area of 54.2 square kilometres (20.9 sq mi) and a mean elevation of 384 metres (1,260 ft) above sea level. Its equilibrium line altitude was at an elevation of 200 m (660 ft) above sea level.^[8]

According to Alekseev,^[10] Anisimov and Tumskoy,^[11] and Makeyev and others,^[12] the glaciers found on Bennett and other islands of the De Long Islands are remnants of small passive ice caps formed during the Last Glacial Maximum (Late Weichselian Epoch) about 17,000 to 24,000 BP. At the time that these ice caps formed, the De Long Islands were major hills within a large subaerial plain, called the Great Arctic Plain, that now lies submerged below the Arctic Ocean and East Siberian Sea.^[13]

Rush/grass, forb, cryptogam tundra covers the Bennett Island. It is tundra consisting mostly of very low-growing grasses, rushes, forbs, mosses, lichens, and liverworts. These plants either mostly or completely cover the surface of the ground. The soils are typically moist, fine-grained, and often hummocky.^[14]

Bennett Island is notable for its associated atmospheric plumes, which have remained a mystery to atmospheric scientists for decades. From time to time, large plumes form over this island, reaching hundreds of miles in length and radiating from the northeast coast of Russia. According to recent studies, hydrothermal eruptions in the vicinity of the island are the cause of their formation, but this does not exclude other mechanisms of their origin, including meteorological ones.^[16][17]