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40-608: Visokoi Island is an uninhabited volcanic island and one the three Traversay Islands that constitute a subgroup of the South Sandwich Islands , in the Southern Ocean . Visokoi consists of one major volcano, Mount Hodson, whose height is usually given as 1,005 metres (3,297 ft). The mountain is mostly covered by glaciers , except for several low areas on the coast like the northern Finger Point and eastern Irving Point. Several parasitic vents are found especially on

80-588: A sector collapse on the western side and a more extensive shelf cut by submarine canyons on the eastern side. From there, a submarine ridge connects Visokoi with Candlemas Island farther south. East of the South Sandwich Islands, the South America Plate subducts beneath the Scotia Plate at a rate of 70 millimetres per year (2.8 in/year). The subduction is responsible for the existence of

120-507: A number of volcanic islands that rise no more than 1 metre (3 ft 3 in) above sea level , often classified as islets or rocks, while some low islands, such as Banaba , Henderson Island , Makatea , Nauru , and Niue , rise over 50 metres (160 ft) above sea level. The two types of islands are often found in proximity to each other, especially among the islands of the South Pacific Ocean , where low islands are found on

160-466: A rate of 70 millimetres per year (2.8 in/year). The subduction is responsible for the existence of the South Sandwich island arc, which is constituted by about eleven islands in an eastward curving chain, and submarine volcanoes such as Protector in the north and Adventure and Kemp in the south. Most of the islands are stratovolcanoes of various sizes. Geologically, Vindication Island resembles

200-473: A thousand Antarctic fur seals were seen at Irving Point in 1964, making it the largest occurrence in the South Sandwich Islands. Visokoi was discovered on the 23 December 1819 by the Thaddeus von Bellingshausen expedition. The proper spelling of the island name is Vysokij . The island can be accessed from Wordie Point and Finger Point, where there are low-lying platforms. Volcanic island There are

240-636: A well-developed vegetation, consisting of algae , lichens and mosses . Soils on the island are less permeable than on other islands in the archipelago, allowing more water retention and thus facilitating vegetation growth. The vegetation forms distinct plant communities, with mats and tall turfs. Mites and springtails inhabit the vegetation. Numerous bird species breed on Vindication Island, including Antarctic fulmars , cape petrels , chinstrap penguins , macaroni penguins , snow petrels . The penguins are concentrated on Chinstrap Point, where in 1964 60,000-100,000 breeding pairs were observed, while

280-431: Is Finger Point and the southernmost Mikhaylov Point. Cliffs and ice falls make up most of the coastline, except at Irving Point where there are an offshore reef and sandy beaches and Finger Point which is a low-lying lava flow . The island is asymmetric, with the western side having higher cliffs and steeper slopes than the eastern side. Most of the inside of the island is covered with heavily crevassed ice, which reaches

320-585: Is a small uninhabited island of the Candlemas Islands in the South Sandwich Islands . It is one of about a dozen islands that make up the South Sandwich island arc , a chain of volcanoes in the Southern Ocean that was discovered in 1775 by James Cook . The volcanism is caused by the subduction of the South American Plate beneath the Sandwich Plate . The island has a rectangular outline and

360-417: Is among the most visited South Sandwich Islands, and once one has overcome the coastal cliffs, traversing the interior is relatively easy. Vindication Island is rectangular, with a 2.1 kilometres (1.3 mi) long side and a 1.6 kilometres (0.99 mi) short side. The corners of the rectangle are the northwestern Crosscut Point cape, the northeastern Braces Point , the southeastern Chinstrap Point and

400-430: Is made up by layers of lava flows , scoria and tuff , intruded by dykes . The tuffs have red, yellow and brown colours. Some surfaces are formed by volcanic ash , while lava flows make up the islets. The oldest rocks are presumably found at the bottom of the cliffs, while lava flows at the surface are probably the youngest rocks. Coastal erosion has removed most of the volcanic pile, so that only about one-fifth of

440-622: Is mostly ice-free save for a shrinking area above 250 metres (820 ft) around Quadrant Peak; in 1964 ice covered about 0.3 square kilometres (0.12 sq mi). Only about one tenth of the island is ice-covered, because the small size of the island limits the area on which snow and ice can accumulate. Separate ice bodies are found on the eastern side, where the main ice cap has left moraines . There are three major drainages that all emanate from Quadrant Peak: An unnamed one going northeast, Leafvein Gulch that runs eastward and Pothole Gulch to

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480-540: Is only about 24 metres (79 ft) deep. Both Candlemas and Vindication rise from the same submarine volcano, and are named the Candlemas Islands . Around the islands the sea is less than 100 metres (330 ft) deep, forming a 12 kilometres (7.5 mi) wide shallow platform with numerous shoals, islets and sea stacks . They are remnants of eroded islands and include Buddha Rock, Castor Rock, Cook Rock, Pollux Rock, Santa Rock, Saw Rock, Tomblin Rock and Trousers Rock. Most of

520-428: Is the remnant of three mostly eroded volcanoes. The highest point of the island, Quadrant Peak , directly overlies the coast. Inland Vindication Island features a rich vegetation, consisting of lichens and mosses , while various bird and penguin species breed along the coasts. There is no evidence of recent volcanic activity. Vindication and Candlemas Island were both discovered on 2 February 1775 by James Cook on

560-399: Is uncertain. Eruptions were recorded in 1830, 1927 and 1930 when passing ships observed smoke columns. There are no tephra layers embedded in ice but scoria lying on ice may represent either recent activity or older eruptions whose products were covered by ice and then re-exposed. An active fumarole associated with the scoria cone at Finger Point was observed in 1930. In 1962 this fumarole

600-514: The HMS ; Resolution . In 1951–1952 the Argentine frigates ARA  Hércules and ARA  Sarandí installed a marker on Vindication, claiming Argentine sovereignty over the island; this is the first recorded landing on the island. The British HMS  Protector landed a party on Vindication in 1956–1957 as part of a larger operation in the South Sandwich Islands, with other visits from

640-515: The Traversay Islands subgroup of the South Sandwich Islands. Icebergs occur in the surrounding waters. The island has an oval shape with a length of 8 kilometres (5.0 mi) and a width of 6 kilometres (3.7 mi); the surface area is about 30.7 square kilometres (11.9 sq mi). The pointy end is east and ends at Irving Point, and the blunt end west with the western Sulphur Point and southwestern Wordie Point. The northernmost point

680-420: The fringing reefs that surround most volcanic islands. Volcanic islands normally rise above a hotspot or subduction zone . Volcanic islands usually range in size between 1 and 104 square kilometres (0.4 and 40 sq mi). Islands above a certain size usually have fresh groundwater , while low islands often do not, so volcanic islands are more likely to be habitable. Many volcanic islands emerge from

720-445: The South Sandwich island arc , which is constituted by about eleven islands in an eastward curving chain, and submarine volcanoes such as Protector in the north and Adventure and Kemp in the south. From north to south Zavodovski, Leskov Island, Visokoi Island, Candlemas Island - Vindication Island , Saunders Island , Montagu Island , Bristol Island - Freezland Rock , Bellingshausen Island , Cook Island - Thule Island emerge from

760-454: The coast in several locations. The total surface area covered by ice in 1962 amounted to 24.1 square kilometres (9.3 sq mi). The 835 metres (2,740 ft) or (more commonly mentioned) 1,005 metres (3,297 ft) high Mount Hodson rises on the western side of the island and has a flat summit. It features a 900 metres (3,000 ft) wide summit crater surrounded by two concentric sector collapse scars. Several scoria cones rise from

800-443: The deep abyss of the ocean, and feature rough or mountainous landscapes in their interiors and a diverse array of summit elevations. Researchers have observed that the island will often be covered by dense tropical forest. These limit settlement on the interior of many islands, forcing communities to develop along the coast. Larger islands may have rivers, resulting in flood hazards. Rivers deliver sediment downstream, which can dominate

840-578: The eastern cinder cones formed, and the western side of the island was subject to coastal erosion . Potassium-argon dating has yielded an age of 300,000 ± 100,000 years for a rock at Sulphur Point, but activity continued into the Holocene and the Finger Point lava flow may be recent. An 18,000 years old tephra layer in the Vostok ice core has been attributed to Visokoi. The occurrence of historical eruptions

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880-424: The eastern part, including Shamrock Hill and an unnamed but probably young cone which form a nunatak . They rise slightly above the ice level and bear no evidence of craters. Finger Point appears to consist of a lava flow with preserved surface features that extends northwards from the scree -covered slopes of Visokoi, forming a low-lying coastal platform. Several islets lie around Visokoi, such as Coffin Rock off

920-457: The eastern side, and one vent close to Finger Point is still hot. Eruptions were reported in 1830, 1927 and 1930. Visokoi is one of the South Sandwich Islands , which lie southeast of South Georgia in the Southern Ocean and extend over a distance of 350 kilometres (220 mi) in north-south direction. Leskov Island is 58 kilometres (36 mi) west and Zavodovski Island 45 kilometres (28 mi) north from Visokoi; together they makes up

960-489: The importance of implementing effective risk mitigation plans that include nature-based solutions to improve societal safety on these islands. These involve leveraging natural processes and ecosystems to reduce hazard impacts. This can include the restoration of natural barriers like mangroves or coral reefs that protect against tsunamis and storm surges or the maintenance of natural water catchments that can mitigate flood risks. Vindication Island Vindication Island

1000-512: The islands are small and volcanic, most showing evidence of activity during the last two centuries. They are subject to intense marine erosion . Submarine volcanoes include Protector Shoals at the northern end and Nelson and Kemp seamounts at the southern end of the island chain. Politically, the South Sandwich Islands are part of the British Overseas Territory of South Georgia and the South Sandwich Islands . Vindication Island

1040-404: The islets lie around Vindication. Some of these rocks make up a series of shoals between the islands. The shelf itself probably formed through marine erosion and scouring by icebergs . The volcano has a base diameter of more than 53 kilometres (33 mi) at 2,500 metres (8,200 ft) and a total volume of about 2,200 cubic kilometres (530 cu mi). Away from the shallow platform,

1080-538: The northeastern coast. The island is surrounded by a 2.3–6 kilometres (1.4–3.7 mi) wide shelf at less than 200 metres (660 ft) depth. The shelf broadens with depth to form a large submarine volcano, which reaches a width of 57 kilometres (35 mi) at 2,500 metres (8,200 ft) depth. The total volume of Visokoi complete with the submarine parts is about 3,000 cubic kilometres (720 cu mi). The submarine edifice has an east-west extension, with numerous small volcanoes, chutes and traces (hummocky terrain) of

1120-410: The older southeastern part of Candlemas Island. Basalt and basaltic andesite make up Vindication Island. Andesite , gabbro and palagonite have been reported as well; the gabbro may be a xenolith . Phenocrysts include olivine , plagioclase and pyroxene . The rocks of Vindication Island and the older series on Candlemas Island define a potassium -poor tholeiitic suite. The island

1160-464: The original volcano remains. The island was probably formed by three separate volcanic centres, two of which were centered offshore of the current island and are now completely eroded. The island is probably younger than one million years and activity may have continued into the Holocene . No historical activity is known from Vindication Island. There is no evidence of recent activity nor of any recently active fumaroles . Vindication Island has

1200-578: The same ship in 1962 and 1964. In 1961, the RRS ; Shackleton landed a boat. In May 1975, the Argentine research vessel ARA  Islas Orcadas investigated seafloor communities in the channel between Vindication and Candlemas. In January 2011, the MS ; Golden Fleece sent a landing party ashore at Chinstrap Point. The name "Vindication Island" refers to the fact that initially, James Cook's report of there being two islands (rather than one or three)

1240-502: The sea. Most of the islands are stratovolcanoes of various sizes. Volcanic rocks are mostly basaltic , but basaltic andesite and andesite are also found. Phenocrysts include clinopyroxene , hypersthene , magnetite , olivine and plagioclase . The rocks are notably iron -rich and define a tholeiitic suite. The island grew during the past one million years by an alternation of pyroclastic rocks and lava flows with columnar jointing, cut by dykes , building one volcano. Later

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1280-431: The shallow water surrounding Visokoi. Antarctic fulmars , cape petrels , chinstrap penguins , gentoo penguins , kelp gulls , macaroni penguins and skuas nest in the cliffs which are ice-free, and on the low coastal platforms especially at Finger Point. More than 100,000 chinstrap penguin breeding pairs occur on Visokoi. Additional seabirds and seals visit the island without clear evidence of reproduction. Almost

1320-473: The shape of the coast and contribute to erosion. Tall volcanic islands are often surrounded by protective fringing or barrier reefs, creating lagoons. The unique geological and geographical characteristics of volcanic islands make them prone to many natural hazards, which are expected to worsen due to climate change . These include volcanic eruptions, earthquakes, tsunamis, landslides, and severe weather events like hurricanes or typhoons. Studies have highlighted

1360-452: The slopes of the volcano drop off steeply into the deep ocean. East of Candlemas and abutting its southeastern side is a large 16 kilometres (9.9 mi) wide submarine embayment, probably the remnant of a large sector collapse . Two other structures interpreted as landslide scars lie north and south of the shelf, which is scalloped by landslide scars. The submarine slopes have wave-like bedforms in many places. Smaller ridges emanate from

1400-403: The southeast. Leafvein Gulch during summer forms a waterfall across the coastal cliffs. Pothole Gulch is fed by meltwater from the small ice cap. The shape of the unnamed drainage implies that it once extended farther west, before coastal erosion truncated it. Vindication Island lies about 4.5 kilometres (2.8 mi) west of Candlemas Island. The Nelson Channel between the two islands

1440-428: The southwestern Knob Point . The entire coastline is made up by steep cliffs that rise above bouldery beaches; the only exception is the valley where Pothole Gulch enters the sea. Offshore lie numerous islets, such as Castor Rock and Pollux Rock south/southwest of Chinstrap Point and an unnamed islet west of Crosscut Point. The island's highest point is Quadrant Peak at 442 m (1,450 ft), and lies in

1480-541: The southwestern corner of the island above Knob Point, dropping almost directly into the sea. A subsidiary peak above Crosscut Point is Splinter Crag , which rises 175 metres (574 ft) above sea level. From there, the island slopes downwards in eastern direction. This asymmetric shape is due to erosion by weather and sea being concentrated on the western side of the island. The inland is formed by tablelands, ridges and creeks, its surface covered with blocky debris from which lavas and pyroclastics emerge. The island

1520-411: The submarine volcano and are interpreted as parts of it, while chutes emanating in all directions formed through mass wasting . A submarine ridge at 1 kilometre (0.62 mi) depth connects the group to Visokoi farther north. West of Candlemas, monogenetic volcanoes are developed on the seafloor. East of the South Sandwich Islands, the South America Plate subducts beneath the Scotia Plate at

1560-498: Was gone, but volcanically heated ground was reported from the same site in 1964. Thermal anomalies are not visible from satellite images. The fumarole was surrounded by a concentric area of algae , lichens and mosses . Away from the fumarole, vegetation is largely absent from Visokoi and consists mostly of lichens growing on bare rocks. Non-vertebrates include mites and springtails while amphipods , brittle stars , bryozoans , sponges and hydrozoans have been recovered from

1600-720: Was not believed. Knob Point was charted in 1930 by Discovery Investigations personnel on the Discovery II , and probably so named because a conspicuous height of land overlooks the point. Vindication Island is one of the South Sandwich Islands , a 320 kilometres (200 mi) long north–south trending island arc to the southeast of South Georgia and the Falklands . They include Zavodovski , Leskov Island , Visokoi , Candlemas Island -Vindication Island, Saunders Island , Montagu Island , Bristol Island and Freezland Rock , Bellingshausen Island , Cook Island and Thule Island . All

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