Vindication Island

Template:Short description Template:Use dmy dates Template:Infobox islands Vindication Island 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 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.

History and toponymyEdit

Vindication and Candlemas Island were both discovered on 2 February 1775 by James Cook aboard Template:Ship.Template:Sfn In 1951–1952 the Argentine frigates Template:Ship and Template:Ship installed a marker on Vindication, claiming Argentine sovereignty over the island;Template:Sfn this is the first recorded landing on the island.Template:Sfn The British Template:Ship landed a party on Vindication in 1956–1957 as part of a larger operation in the South Sandwich Islands,Template:Sfn with other visits from the same ship in 1962Template:Sfn and 1964.Template:Sfn In 1961, the Template:Ship landed a boat.Template:Sfn In May 1975, the Argentine research vessel Template:Ship investigated seafloor communities in the channel between Vindication and Candlemas.Template:Sfn In January 2011, the Template:Ship sent a landing party ashore at Chinstrap Point.Template:Sfn

The name "Vindication Island" refers to the fact that initially, James Cook's report of there being two islands (rather than one or three) was not believed.Template:Sfn Knob Point was charted in 1930 by Discovery Investigations personnel on Template:Ship, and probably so named because a conspicuous height of land overlooks the point.Template:Sfn

GeographyEdit

Vindication Island is one of the South Sandwich Islands, a Template:Convert 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 the islands are small and volcanic, most showing evidence of activity during the last two centuries.Template:Sfn 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.Template:Sfn Politically, the South Sandwich Islands are part of the British Overseas Territory of South Georgia and the South Sandwich Islands.Template:Sfn Vindication Island is among the most visited South Sandwich Islands, and once one has overcome the coastal cliffs, traversing the interior is relatively easy.Template:Sfn

Vindication Island is rectangular, with a Template:Convert long side and a Template:Convert short side.Template:Sfn The corners of the rectangle are the northwestern Crosscut Point cape, the northeastern Braces Point, the southeastern Chinstrap Point and the southwestern Knob Point.Template:Sfn The entire coastline is made up by steep cliffsTemplate:Sfn 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.Template:Sfn

The island's highest point is Quadrant Peak at Template:Cvt,Template:Sfn and lies in the southwestern corner of the island above Knob Point,Template:Sfn dropping almost directly into the sea.Template:Sfn A subsidiary peak above Crosscut Point is Splinter Crag, which rises Template:Convert above sea level. From there, the island slopes downwards in eastern direction.Template:Sfn This asymmetric shape is due to erosion by weather and sea being concentrated on the western side of the island.Template:Sfn The inland is formed by tablelands, ridges and creeks,Template:Sfn its surface covered with blocky debris from which lavas and pyroclastics emerge.Template:Sfn

The island is mostly ice-freeTemplate:Sfn save for a shrinking area above Template:Convert Template:Sfn around Quadrant Peak;Template:Sfn in 1964 ice covered about Template:Convert.Template:Sfn Only about one tenth of the island is ice-covered,Template:Sfn because the small size of the island limits the area on which snow and ice can accumulate.Template:Sfn Separate ice bodies are found on the eastern side, where the main ice cap has left moraines.Template:Sfn There are three major drainages that all emanate from Quadrant Peak:Template:Sfn An unnamed one going northeast, Leafvein Gulch that runs eastward and Pothole Gulch to the southeast.Template:Sfn Leafvein Gulch during summer forms a waterfall across the coastal cliffs.Template:Sfn 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.Template:Sfn

Submarine structureEdit

Vindication Island lies about Template:Convert west of Candlemas Island.Template:Sfn The Nelson Channel between the two islands is only about Template:Convert deep.Template:Sfn Both Candlemas and Vindication rise from the same submarine volcano, and are named the Candlemas Islands.Template:Sfn Around the islands the sea is less than Template:Convert deep,Template:Sfn forming a Template:Convert wide shallow platform with numerous shoals, islets and sea stacks.Template:Sfn They are remnants of eroded islandsTemplate:Sfn and include Buddha Rock, Castor Rock, Cook Rock, Pollux Rock, Santa Rock, Saw Rock, Tomblin Rock and Trousers Rock. Most of the islets lie around Vindication.Template:Sfn Template:Sfn Some of these rocks make up a series of shoals between the islands.Template:Sfn The shelf itself probably formed through marine erosion and scouring by icebergs.Template:Sfn

The volcano has a base diameter of more than Template:Convert at Template:Convert Template:Sfn and a total volume of about Template:Convert.Template:Sfn Away from the shallow platform, the slopes of the volcano drop off steeply into the deep ocean.Template:Sfn East of Candlemas and abutting its southeastern side is a large Template:Convert wide submarine embayment, probably the remnant of a large sector collapse.Template:Sfn Two other structures interpreted as landslide scars lie north and south of the shelf,Template:Sfn which is scalloped by landslide scars.Template:Sfn The submarine slopes have wave-like bedforms in many places.Template:Sfn Smaller ridges emanate from the submarine volcano and are interpreted as parts of it,Template:Sfn while chutes emanating in all directions formed through mass wasting.Template:Sfn A submarine ridge at Template:Convert depth connects the group to Visokoi farther north.Template:Sfn West of Candlemas, monogenetic volcanoes are developed on the seafloor.Template:Sfn

GeologyEdit

East of the South Sandwich Islands, the South America Plate subducts beneath the Scotia Plate at a rate of Template:Convert. The subduction is responsible for the existence of the South Sandwich island arc, which is constituted by about eleven islandsTemplate:Sfn in an eastward curving chain,Template:Sfn and submarine volcanoes such as Protector in the north and Adventure and Kemp in the south.Template:Sfn Most of the islands are stratovolcanoes of various sizes.Template:Sfn Geologically, Vindication Island resembles the older southeastern part of Candlemas Island.Template:Sfn

CompositionEdit

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

Geologic historyEdit

The island is made up by layers of lava flows, scoria and tuff,Template:Sfn intruded by dykes.Template:Sfn The tuffs have red, yellow and brown colours.Template:Sfn 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.Template:Sfn Coastal erosion has removed most of the volcanic pile,Template:Sfn so that only about one-fifth of the original volcano remains.Template:Sfn 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.Template:Sfn

The island is probably younger than one million yearsTemplate:Sfn and activity may have continued into the Holocene.Template:Sfn No historical activity is known from Vindication Island.Template:Sfn There is no evidence of recent activityTemplate:Sfn nor of any recently active fumaroles.Template:Sfn

Climate and vegetationEdit

Vindication Island has a well-developed vegetation, consisting of algae Template:Efn, lichens Template:Efn and mosses Template:Efn.Template:Sfn Soils on the island are less permeable than on other islands in the archipelago, allowing more water retention and thus facilitating vegetation growth.Template:Sfn The vegetation forms distinct plant communities, with mats and tall turfs.Template:Sfn Mites Template:Efn and springtails Template:Efn inhabit the vegetation.Template:Sfn

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 the seabirds nest in cliffs.Template:Sfn A survey in 2011 showed that the penguin populations were either stable or increasing.Template:Sfn Other animals that visit Vindication Island include Antarctic fur seals, brown skuas, Dominican gulls, elephant seals, leopard seals, shags, Weddel seals and Wilson's petrels.Template:Sfn Template:Sfn