Alexander Island, which is also known as Alexander I Island, Alexander I Land, Alexander Land, Alexander I Archipelago, and Zemlja Alexandra I, is the largest island of

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest contine ...

. It lies in the Bellingshausen Sea west of Palmer Land,

Antarctic Peninsula The Antarctic Peninsula, known as O'Higgins Land in Chile and Tierra de San Martín in Argentina, and originally as Graham Land in the United Kingdom and the Palmer Peninsula in the United States, is the northernmost part of mainland Antarctic ...

from which it is separated by

Marguerite Bay Marguerite Bay or Margaret Bay is an extensive bay on the west side of the Antarctic Peninsula, which is bounded on the north by Adelaide Island and on the south by Wordie Ice Shelf, George VI Sound and Alexander Island. The mainland coast on the ...

and George VI Sound. The

George VI Ice Shelf The George VI Ice Shelf () is an extensive ice shelf that occupies George VI Sound which separates Alexander Island from Palmer Land in Antarctica. The ice shelf extends from Ronne Entrance, at the southwest end of the sound In physics ...

entirely fills George VI Sound and connects Alexander Island to Palmer Land. The island partly surrounds

Wilkins Sound Wilkins Sound is a seaway in Antarctica that is largely occupied by the Wilkins Ice Shelf. It is located on the southwest side of the Antarctic Peninsula between the concave western coastline of Alexander Island and the shores of Charcot Island ...

, which lies to its west.Stewart, J. (2011) ''Antarctic An Encyclopedia'' McFarland & Company Inc, New York. 1776 pp. . Alexander Island is about long in a north–south direction, wide in the north, and wide in the south. Alexander Island is the second-largest uninhabited island in the world, after Devon Island.

History

Alexander Island was discovered on January 28, 1821, by a Russian expedition under

Fabian Gottlieb von Bellingshausen Fabian Gottlieb Thaddeus von Bellingshausen (russian: Фадде́й Фадде́евич Беллинсга́узен, translit=Faddéy Faddéevich Bellinsgáuzen; – ) was a Russian naval officer, cartographer and explorer, who ultimatel ...

, who named it Alexander I Land for the reigning

Tsar Tsar ( or ), also spelled ''czar'', ''tzar'', or ''csar'', is a title used by East Slavs, East and South Slavs, South Slavic monarchs. The term is derived from the Latin word ''Caesar (title), caesar'', which was intended to mean "emperor" i ...

Alexander I of Russia Alexander I (; – ) was Emperor of Russia from 1801, the first King of Congress Poland from 1815, and the Grand Duke of Finland from 1809 to his death. He was the eldest son of Emperor Paul I and Sophie Dorothea of Württemberg. The son of Gra ...

. What, in fact, is an island, was believed to be part of the Antarctic mainland until 1940. Its insular nature was proven in December 1940, by a two-person

sledge A sled, skid, sledge, or sleigh is a land vehicle that slides across a surface, usually of ice or snow. It is built with either a smooth underside or a separate body supported by two or more smooth, relatively narrow, longitudinal runners s ...

party composed of

Finn Ronne Finn Ronne (December 20, 1899 – January 12, 1980) was a Norwegian-born U.S. citizen and Antarctic explorer. Background Finn Ronne was born in Horten, in Vestfold county, Norway. His father, Martin Rønne (1861–1932), was a polar explore ...

and

Carl Eklund Carl Robert Eklund (January 27, 1909 – November 3, 1962) was a leading American specialist in ornithology and geographic research in both the north and south polar regions. He was appointed as the first Scientific Station Leader of the Wilkes S ...

of the

United States Antarctic Service The United States Antarctic Program (or USAP; formerly known as the United States Antarctic Research Program or USARP and the United States Antarctic Service or USAS) is an organization of the United States government which has presence in the A ...

. In the 1950s, a British base administered as part of the

British Antarctic Territory The British Antarctic Territory (BAT) is a sector of Antarctica claimed by the United Kingdom as one of its 14 British Overseas Territories, of which it is by far the largest by area. It comprises the region south of 60°S latitude and between ...

was constructed as

Fossil Bluff Fossil Bluff is a seasonal British aircraft refuelling station located on the east coast of Alexander Island in Antarctica. In operation since 1961, its facilities provide fuel, storage, and ancillary support for British exploration and operation ...

(''Base KG''). The island was claimed by the United Kingdom in 1908 as part of the

. Territorial claims have also been set by both

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

(in 1940) and

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

(in 1942). Currently, under the

Antarctic Treaty The Antarctic Treaty and related agreements, collectively known as the Antarctic Treaty System (ATS), regulate international relations with respect to Antarctica, Earth's only continent without a native human population. It was the first arms ...

no claim has been officially recognized. The island contains the British

meteorological Meteorology is a branch of the atmospheric sciences (which include atmospheric chemistry and physics) with a major focus on weather forecasting. The study of meteorology dates back millennia, though significant progress in meteorology did not ...

centre and refuelling base.

Geography

Rocky mountain face, Alexander Island (6280674894)

The surface of Alexander Island is predominantly ice-covered. There exist some exposed

nunatak A nunatak (from Inuit ''nunataq'') is the summit or ridge of a mountain that protrudes from an ice field or glacier that otherwise covers most of the mountain or ridge. They are also called glacial islands. Examples are natural pyramidal peaks. ...

s and a few ice-free areas of significant size, including Ablation Point Massif. The nunataks are the peaks of north–south trending mountain ranges and hills. They include the Colbert, Havre, Lassus, Rouen,

Sofia University Sofia University, "St. Kliment Ohridski" at the University of Sofia, ( bg, Софийски университет „Св. Климент Охридски“, ''Sofijski universitet „Sv. Kliment Ohridski“'') is the oldest higher education ...

, and Walton Mountains, the Staccato Peaks, the Lully Foothills, the Finlandia Foothills, the Elgar Uplands, and the

Douglas Range The Douglas Range () is a sharp-crested range, with peaks rising to 3,000 metres, extending 120 km (75 mi) in a northwest–southeast direction from Mount Nicholas to Mount Edred and forming a steep east escarpment of Alexander Island w ...

. These mountains, peaks, hills, and uplands are surrounded by a permanent ice sheet, which consists of glaciers that flow off of Alexander Island. These glaciers flow west into the

Bach Johann Sebastian Bach (28 July 1750) was a German composer and musician of the late Baroque period. He is known for his orchestral music such as the ''Brandenburg Concertos''; instrumental compositions such as the Cello Suites; keyboard wo ...

and Wilkins Ice Shelves and Bellingshausen Sea, and east into the George VI Ice Shelf. The George VI Ice Shelf is fed by both by outlet glaciers from the ice cap on Palmer Land and Alexander Island. Another notable feature of Alexander Island is Hodgson Lake. Hodgson Lake is a former

subglacial lake A subglacial lake is a lake that is found under a glacier, typically beneath an ice cap or ice sheet. Subglacial lakes form at the boundary between ice and the underlying bedrock, where gravitational pressure decreases the pressure melting point ...

that has emerged from under an ice sheet that had covered it. Hodgson Lake is long by , and has a deep water column that lies sealed beneath a thick perennial lake ice. The northern side of Hodgson Lake is bounded by the Saturn Glacier, which flows east into George VI Sound, while the southern side of Hodgson Lake is bounded by the northern face of Citadel Bastion. During the Last Glacial Maximum, Hodgson Lake was covered by the ice sheet at least thick. This ice sheet started thinning about 13,500 years ago. It retreated and left Hodgson Lake covered by perennial ice sometime before 11,000 years ago. This lake has been covered by perennial ice since that time. Other features on the island include Damocles Point and Mount Tyrrell.

Brahms Inlet

Brahms Inlet () is an ice-filled inlet, long and wide, indenting the north side of

Beethoven Peninsula The Beethoven Peninsula is a deeply indented, ice-covered peninsula, long in a northeast–southwest direction and wide at its broadest part, forming the southwest part of Alexander Island, which lies off the southwestern portion of the Antarcti ...

on Alexander Island between Harris Peninsula and

Derocher Peninsula Derocher Peninsula () is a snow-covered peninsula between Brahms Inlet and Mendelssohn Inlet on the north side of Beethoven Peninsula, Alexander Island, Antarctica. It was photographed from the air by the Ronne Antarctic Research Expedition, 194 ...

, while the headland

Mazza Point Mazza Point () is a snow-covered headland lying between Brahms Inlet and Mendelssohn Inlet, marking the northwest end of Derocher Peninsula, a minor peninsula that extends in a northwest point from Beethoven Peninsula, situated in the southwest ...

lies immediately northeast of the inlet and Mount Grieg lies immediately southeast of the base of Brahms Inlet. It was observed from the air and first mapped by the

Ronne Antarctic Research Expedition The Ronne Antarctic Research Expedition (RARE) was an expedition from 1947–1948 which researched the area surrounding the head of the Weddell Sea in Antarctica. Background Finn Ronne led the RARE which was the final privately sponsored exp ...

(RARE), 1947–48, and re-mapped from the RARE air photos by Derek J.H. Searle of the

Falkland Islands Dependencies Survey The British Antarctic Survey (BAS) is the United Kingdom's national polar research institute. It has a dual purpose, to conduct polar science, enabling better understanding of global issues, and to provide an active presence in the Antarctic on ...

in 1960. It was named by the

UK Antarctic Place-Names Committee The UK Antarctic Place-Names Committee (or UK-APC) is a United Kingdom government committee, part of the Foreign and Commonwealth Office, responsible for recommending names of geographical locations within the British Antarctic Territory (BAT) and ...

after Johannes Brahms, the German composer.

Harris Peninsula

Harris Peninsula () is a broad snow-covered peninsula surmounted by

Mount Lee Mount Lee is a peak in the Santa Monica Mountains, located in Griffith Park in Los Angeles, California, USA. The Hollywood Sign is located on its southern slope. History The original unnamed peak was one of the "three sisters" along with C ...

, between

Verdi Inlet Verdi Inlet () is an ice-filled inlet lying between Pesce Peninsula and Harris Peninsula, on the north side of the Beethoven Peninsula, situated in the southwest portion of Alexander Island, Antarctica. The inlet was observed from the air and firs ...

and Brahms Inlet on the north side of the

, located in the southwest portion of Alexander Island,

. It is one of eight peninsulas of Alexander Island. It was photographed from the air by the RARE, 1947–48, and mapped from these photographs by D. Searle of the

, 1960. It was named by the

Advisory Committee on Antarctic Names The Advisory Committee on Antarctic Names (ACAN or US-ACAN) is an advisory committee of the United States Board on Geographic Names responsible for recommending commemorative names for features in Antarctica. History The committee was established ...

for Commander Michael J. Harris,

U.S. Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage of ...

Commanding Officer The commanding officer (CO) or sometimes, if the incumbent is a general officer, commanding general (CG), is the officer in command of a military unit. The commanding officer has ultimate authority over the unit, and is usually given wide latitud ...

of Squadron VXE-6, from May 1982 to May 1983.

Lyadov Glacier

Lyadov Glacier () is a glacier flowing east-northeast from Harris Peninsula, Alexander Island, into Brahms Inlet. It was named by the USSR Academy of Sciences in 1987 after

Anatoly Lyadov Anatoly Konstantinovich Lyadov (russian: Анато́лий Константи́нович Ля́дов; ) was a Russian composer, teacher, and conductor. Biography Lyadov was born in 1855 in St. Petersburg, into a family of eminent Russian ...

(1855–1914), a Russian composer.

Geology

According to Hole, "The geology of Alexander Island can be attributed mainly to processes associated with the

subduction Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, ...

of proto-Pacific

oceanic crust Oceanic crust is the uppermost layer of the oceanic portion of the tectonic plates. It is composed of the upper oceanic crust, with pillow lavas and a dike complex, and the lower oceanic crust, composed of troctolite, gabbro and ultramafic c ...

along the western margin of the Antarctic Peninsula, from latest

Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...

to Late Tertiary times." The LeMay Group

accretionary prism An accretionary wedge or accretionary prism forms from sediments accreted onto the non-subducting tectonic plate at a convergent plate boundary. Most of the material in the accretionary wedge consists of marine sediments scraped off from the do ...

complex, along with plutonic and volcanic rocks, are prevalent along the western portion of the island. The LeMay Group consists of variably-deformed and

metamorphosed Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causi ...

sedimentary and igneous rocks. Although it is dominated by deformed

arkosic Arkose () or arkosic sandstone is a detrital sedimentary rock, specifically a type of sandstone containing at least 25% feldspar. Arkosic sand is sand that is similarly rich in feldspar, and thus the potential precursor of arkose. Quartz is c ...

sedimentary rocks, it includes turbiditic

greywackes Greywacke or graywacke ( German ''grauwacke'', signifying a grey, earthy rock) is a variety of sandstone generally characterized by its hardness, dark color, and poorly sorted angular grains of quartz, feldspar, and small rock fragments or li ...

, black mudstones, and conglomerates. The thick

Upper Jurassic The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 163.5 ± 1.0 to 145.0 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic strata.Owen 1987. In European lithostratigraphy, the na ...

to Lower Cretaceous Fossil Bluff Group sedimentary rocks outcrop as a long by wide belt along the eastern coast. This Fossil Bluff Group consists of a basal deep-marine assemblage thick, overlain by a mudstone assemblage up to thick, followed by a shallow-marine assemblage of coarsening upward sandstones.

Alkali basalt Alkali basalt or alkali olivine basalt is a dark-colored, porphyritic volcanic rock usually found in oceanic and continental areas associated with volcanic activity, such as oceanic islands, continental rifts and volcanic fields. Alkali basalt ...

s erupted after the cessation of subduction. These range in age from the

tephrite Tephrite is an igneous, volcanic (extrusive) rock, with aphanitic to porphyritic texture. Mineral content is usually abundant feldspathoids (leucite or nepheline), plagioclase, and lesser alkali feldspar. Pyroxenes (clinopyroxenes) are commo ...

s at Mount Pinafore (5.5–7.6 Ma), to the

basanite Basanite () is an igneous, volcanic (extrusive) rock with aphanitic to porphyritic texture. It is composed mostly of feldspathoids, pyroxenes, olivine, and plagioclase and forms from magma low in silica and enriched in alkali metal oxides that ...

s at

Rothschild Island Rothschild Island is a black rugged island long, mainly ice-covered but surmounted by prominent peaks of Desko Mountains in Antarctica, west of the north part of Alexander Island in the north entrance to Wilkins Sound. History The island wa ...

(5.5 Ma) and Hornpipe Heights (2.5 Ma), to the alkali and

olivine basalt Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low- viscosity lava rich in magnesium and iron ( mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 9 ...

s on

(<1-2.5 Ma).Macdonald, D.I.M. and P.J. Butterworth (1990) "The stratigraphy, setting and hydrocarbon potential of the Mesozoic sedimentary basins of the Antarctic Peninsula." in B. John, ed., pp. 101–125. ''Antarctica as an exploration frontier; hydrocarbon potential, geology, and hazards''. AAPG Studies in Geology. vol. 31 American Association of Petroleum Geologists, Tulsa, Oklahoma. The LeMay Range Fault trends N-S, parallel to the George VI Sound, and the Fossil Bluff Formation is downfaulted to the east of this fault against the LeMay Group. Sand dykes are found against this fault zone and in many other parts of the Fossil Bay Formation. Fossils within the Fossil Bluff Formation include

ammonite Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids (i.e., octopuses, squid and cuttlefish ...

s, belemnites,

bivalve Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, biva ...

s, and

serpulid The Serpulidae are a family of sessile, tube-building annelid worms in the class Polychaeta. The members of this family differ from other sabellid tube worms in that they have a specialized operculum that blocks the entrance of their tubes wh ...

References

* * * {{Authority control Chilean Antarctic Territory Argentine Antarctica British Antarctic Territory Bulgaria and the Antarctic Islands of Palmer Land