Остров Беннетта: История и геология арктического острова

Island in the East Siberian Sea
the Antarctic island group

Bennett Island (; ) is the largest of the De Long Islands in the northern part of the East Siberian Sea. The area of this island is approximately and it has a tombolo at its eastern end. The highest point of the island is 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 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. 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. 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.

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 thick sequence of argillites with minor amounts of siltstone, and limestone that contain Middle Cambrian trilobites and 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.

Little has been published about the climatology of Bennett Island in the English language literature. Dr. Glazovskiy stated that the annual precipitation on Bennett Island varied from at sea level to 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 All of these glaciers were perched on high, basaltic plateaus bounded by steep scarp like slopes. In 1992, Dr. Verkulich and others Anisimov and Tumskoy, and Makeyev and others, 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.

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.

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. Since then, the main hypotheses for the formation of plumes have been the assumption that they are caused by volcanoes, outbursts of some gas, military tests, as well as the assumption of their meteorological origin. Today, the version of periodic hydrothermal eruptions near the island is considered the most reliable.

Analysis of satellite images from 1973 to 1986 indicated the cyclicity in the appearance of atmospheric plumes over Bennett Island. It was the reason for the opinion, that they most likely have meteorological nature, which is similar to Karman vortex streets. A total of 152 such events were recorded, one of the last of March 12, 2008 was studied separately. It turned out that it was larger than expected if it had a meteorological nature. The length of the plume was , the volume exceeded Also its height was higher than the relief of Bennett Island. The first spotted eruption of 1983 lasted 6 hours, but the duration of these events can reach several days. The volume of ejected solid material reaches , which corresponds to small volcanic eruptions. Subsequent comparison of bathymetric data of seafloor topography around the island showed significant differences from the topography of the 20th century, with the appearance of new cone shaped shoals in places that corresponded well to the location of the plume's origin. Analysis of samples of marine sediments near the island showed a recent interaction with hydrothermal solutions, since these cone shaped formations of ferromanganese composition contain the mineral todorokite, which is common only in hot spring sediments. Thus, events with the formation of vapor gas plumes occur in the relatively high temperature environment of the modern hydrothermal system and are more related to hydrothermal eruptions than to volcanic ones. And by analogy with conventional geysers, the frequency of events is determined by the time it takes for the aforementioned hydrothermal system to restore water reserves and to warm it up for the next eruption. It is assumed that one of these volcanic cones could be observed by the De Long expedition. Such volcanic formations are usually quickly destroyed by ocean waves or sea ice and do not remain on the surface for a long time.