Wrangel Island

Wrangel Island is an island in the Arctic Ocean, between the Chukchi Sea and East Siberian Sea. Wrangel Island lies astride the 180° meridian. The International Date Line is displaced eastwards at this latitude to avoid the island as well as the Chukchi Peninsula on the Russian mainland. The closest land to Wrangel Island is the tiny and rocky Herald Island located 60 km (37 mi) to the east. The distance to the closest point on the mainland is 140 km (87 mi). Wrangel Island may have been the last place on earth where mammoths survived.

Most of Wrangel Island, and Herald Island, is a federally protected nature sanctuary administered by Russia's Ministry of Natural Resources and Environment. The island, and its surrounding waters, were classified as a "Zapovednik" (a "strict nature reserve") in 1976 and, as such, receive the highest level of protection and exclude practically all human activity other than for scientific purposes. The Chukotka Regional government extended the marine protected area out to 24 nautical miles in 1999. As of 2003, there were four rangers who reside on the island year-round. In addition a core group of about 12 scientists conduct research during the summer months.

Wrangel Island is about 125 km (78 mi) wide and 7,600 km2 (2,900 sq mi) in area. It consists of a southern coastal plain that is as wide as 15 km (9.3 mi); a central belt of low-relief mountains; and a northern coastal plain that is as wide as 25 km (16 mi). The east-west trending central mountain belt, the Tsentral'nye Mountain Range, is as much as 40 km (25 mi) wide and 145 km (90 mi) long from coast to coast. Typically, the mountains are a little over 500 m (1,600 ft) above mean sea level. The highest mountain on this island is Sovetskaya Mountain with an elevation of 1,096 m (3,596 ft) above mean sea level. The east-west trending mountain range terminates at sea cliffs at either end of the island.

Wrangel Island belongs administratively to the Chukotka Autonomous Okrug of the Russian Federation. This rocky island has a weather station and, formerly, two Chukchi fishing settlements on the southern side of the island (Ushakovskoye and Zvyozdny on the shore of Somnitelnaya Bay).

Geology

Wrangel Island consists of folded, faulted, and metamorphosed volcanic, intrusive, and sedimentary rocks ranging in age from Upper Precambrian to Lower Mesozoic. The Precambrian rocks, which are about 2 km (1.2 mi) thick, consist of Upper Proterozoic sericite and chlorite slate and schist that contain minor amounts of metavolcanic rocks, metaconglomerates, and quartzite. These rocks are intruded by metamorphosed gabbro, diabase, and felsic dikes and sills and granite intrusions. Overlying the Precambrian strata are up to 2.25 km (1.4 mi) of Upper Silurian to Lower Carboniferous consisting of interbedded sandstone, siltstone, slate, argillite, some conglomerate and rare limestone and dolomite. These strata are overlain by up to 2.15 km (1.34 mi) of Carboniferous to Permian limestone, often composed largely of crinoid plates, that is interbedded with slate, argillite and locally minor amounts of thick breccia, sandstone, and chert. The uppermost stratum consists of 0.7 to 1.5 km (0.43 to 0.93 mi) of Triassic clayish quartzose turbidites interbedded with black slate and siltstone.

A thin veneer of Cenozoic gravel, sand, clay and mud underlie the coastal plains of Wrangel Island. Late Neogene clay and gravel, which are only a few tens of meters thick, rest upon the eroded surface of the folded and faulted strata that comprise Wrangel Island. Indurated Pliocene mud and gravel, which are only a few meters thick, overlie the Late Neogene sediments. Sandy Pleistocene sediments occur as fluvial sediments along rivers and streams and as a very thin and patchy surficial layer of either colluvium or eluvium.

Flora and fauna

Wrangel Island is a breeding ground for polar bears (having the highest density of dens in the world), seals, walrus, and lemmings. During the summer it is visited by many types of birds. Arctic foxes also make their home on the island. Cetaceans such as bowhead whales, gray whales, and belugas can be seen close to shore.

Woolly mammoths survived there until 2500–2000 BC, the most recent survival of all known mammoth populations. Isolated from the mainland for 6000 years, about 500 to 1000 mammoths lived on the island at a time.

Domestic reindeer were introduced in the 1950s and their numbers are managed at around 1,000 in order to reduce their impact on nesting bird grounds. In 1975, the musk ox was also introduced. The population has grown from 20 to about 200 animals. In 2002, wolves were spotted on the island; wolves lived on the island in historical times.

The flora includes 417 species of plants, double that of any other Arctic tundra territory of comparable size and more than any other Arctic island. Forest occupies about 15% of the island's area. For these reasons, the island was proclaimed the northernmost World Heritage Site in 2004.

Climate

Wrangel Island has a severe polar climate. The region is blanketed by dry and cold Arctic air masses for most of the year. Warmer and more humid air can reach the island from the south-east during summer. Dry and heated air from Siberia comes to the island periodically.

Wrangel Island is influenced by both the Arctic and Pacific air masses. One consequence is the predominance of high winds. The island is subjected to "cyclonic" episodes characterized by rapid circular winds. It is also an island of mists and fogs.

Winters are prolonged and are characterized by steady frosty weather and high northerly winds. During this period the temperatures usually stay well below freezing for months. In February and March there are frequent snow-storms with wind speeds of 140 km/h (87 mph) or above.

There are noticeable differences in climate between the northern, central and southern parts of the island. The central and southern portions are warmer, with some of their valleys having semi-continental climates that support a number of sub-Arctic steppe-like meadow species. This area has been described as perhaps being a relict of the Ice Age Mammoth steppe, along with certain areas along the northwestern border between Mongolia and Russia.

The short summers are cool but comparatively mild as the polar day generally keeps temperatures above 0 °C (32 °F). Some frosts and snowfalls occur, and fog is common. Warmer and drier weather is experienced in the center of the island because the interior's topography encourages foehn winds. As of 2003, the frost-free period on the island was very short, usually not more than 20 to 25 days, and more often only two weeks. Average relative humidity is about 83%.