User:Martinvl/sandbox/sandbox1

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The Patagonian Shelf is part of the South American continental shelf on the Atlantic seaboard, south of about 35°S. It adjoinins the coasts of Uruguay, Argentina and the Falkland Islands. Various authorities quote different dimensions of the shelf, depending on how they define its limits. Quoted statistics cites its area as being from 1.2 to 2.7 million square kilometres and its maximum width as being between 760 and 850 kilometres.[1][2]

The Falklands Trough separates the Patagonian Shelf from the Scotia Arc.[3]

Old text

The

South Atlantic Ocean between 51°S and 53°S on a projection of the Patagonian Shelf. In ancient geological time this shelf was part of Gondwana, which around 400 million years ago broke from what is now Africa and drifted westwards relative to Africa.[4] Today the islands are subjected to the Roaring Forties
, winds that shape both their geography and climate.

The Falklands comprise two main islands, West Falkland and East Falkland (in Spanish Isla Gran Malvina and Isla Soledad respectively), and about 776 small islands.[5]

Geology

Old text from here

Location of the Falkland Islands in Gondwana

The

pre-Cambrian era more than 1000 million years ago, when Proterozoic granites and gneisses were laid down in Gondwana. These rocks became part of the Cape Meredith formation and outcrop at the Cape.[6] During the Siluro-Devonianera, these rocks were overlain with quartzose and subarkosic sandstones with some siltstone and mudstone, rocks that are particularly erosion- and weather-resistant giving these parts of the islands a rugged landscape and coastline.[7]

Tectonic forces continued to form the region: a mountainous chain formed, part of which now creates Wickham Heights on East Falkland Island and extends westwards through West Falkland into the Jason Islands. A basin developed and was filled with land-based, or

terrigenous, sediments. These layers of sand and mud filled the basin as it sank and as they hardened they produced the rocks of the sedimentary Lafonia Group of the Falklands. These rocks are similar to those in southern Africa's Karoo basin.[8]

About 290 million years ago, in the

Tillite Formation in the Falklands. Identical rocks are found in southern Africa.[6]

During the break-up of Gondwana and the formation of the

African continent and drifted westwards, dividing and rotating as they did so before settling on the Patagonian Shelf.[7] Most of the layers of West Falkland and its surrounding islands are slightly inclined from the horizontal. This inclination shows different types of rocks in different places. The quartzites of Port Stephens and Stanley are more resistant than the arenaceous sediments of the formation at Fox Bay. The Hornby Mountains, near Falkland Sound
have experienced tectonic forces of uplift and folding which has inclined the quartzite beds of Stanley to the vertical.

Rocks from the more recent geological periods such as the Jurassic, Cretaceous, and Tertiary periods usually contain lime-rich rocks. The absence of such rocks has led to an acidic substrate which manifests itself in the nature of the soil.[7].}}

Topological description

Old text from here

The Falkland Islands are an

South Atlantic Ocean on a projection of the Patagonian Shelf. The two principal islands, East Falkland and West Falkland account for 91% of the land area. These two islands, which have a combined distance of 220 km (140 mi) from east to west and 140 km (87 mi) from north to south, are separated by the Falkland Sound, a channel that averages 20 km (12 mi) in width and have a typical depth of 40 metres (22 fathoms).[9][10][11] Cape Meredith on West Falkland is about 400 km (250 mi) north-west of the tip of Tierra del Fuego and Westpoint, also on West Falkland and adjacent to West Point Island, is about 500 km (310 mi) from the Patagonian
coast.

East Falkland

San Carlos Water, one of many inlets on East Falkland. The islands are heavily indented by sounds and fjords

East Falkland, which has an area of 6,605 km2 (2,550 square miles), a little over half the total area of the islands[12] consists of two land masses of approximately equal size - the southerly part known as Lafonia but the northerly part has no specific name. These land masses are joined by an isthmus of width 2.2 kilometres (1.4 mi)[13] that separates two deep fjords, Choiseul Sound and Brenton Loch-Grantham Sound from each other. The island's 1,668.7 km (1,036.9 miles) coastline has many smaller bays, inlets and headlands.[12] Over 70% of the population of the Falkland Islands live in the capital, Stanley which is located in East Falkland.

The northern part of the island, apart from the coastal strip bordering the

anchorage
for shipping.

In contrast, Lafonia is underlain by Mesozoic rocks (sandstone), a younger rock than the Palaeozoic rock to the north, giving a flatter landscape than is seen elsewhere on the island.[14][15] Sheets of liquid basalt intruded into the cracks that formed between the sedimentary layers. The resulting solidified sheets can now be seen in the form of dikes that cut the oldest sedimentary layers, those that lie principally in the southern part of East Falkland and in South Africa.[8]

West Falkland

West Falkland has an area of 4,532 square kilometres (1,750 square miles), making it a smaller than East Falkland.

Hornby Hills, is 700 metres (2,300 ft) above sea level. The Hornby Hills which are the principal range on the island run approximately north-south parallel with Falkland Sound
. [18] Geologically this range is a continuation of the Wickham Heights on East Falkland, but during the migration of Gwondaland from Africa, the

In West Falkland there are several dykes that cut the rocks of the western islands, but these dykes, unlike the previous ones, are chemically more unstable and have been eroded. The only indications of their existence are the aligned linear depressions. In the margins of these depressions there is evidence of contact baking or hornfels formation adjacent to the once molten basalt dyke.

West Falkland is more hilly on the side closest to East Falkland. The southernmost point of West Falkland is Cape Meredith, and the most south-westerly point is Calm Head. On the southerly side lie high cliffs with an abundance of seabirds.

Smaller islands

Albatross colony on Westpoint
Stone runs on Weddell Island

In addition to the two main islands, the Falkland Islands have over 700 further islands, many no more than a few hectares in area. The islands to the north west of West Falkland include

Saunders Island (131 km2), Carcass Island, West Point Island and the Jason group of islands
(33 km2) that lie some 40 kilometres (25 mi) from West Falkland.

The principal islands to the south west of West Falkland include

Barren Island. In addition, Beauchene Island
, a rocky outcrop lies some 60 kilometres (37 mi) from the Lafonia coast.

Many of the islands are nature reserves, either in whole or in part.

Sea Bed

The Patagonian Shelf, which in ancient geological time was part of Gondwana and which broke from what is now Africa, drifted westwards relative to Africa is now the widest continental shelf in the world covering 1,200,00 km2.[19] It protrudes some 760 km (470 mi) into the

South Atlantic Ocean from the Patagonian coastline and slopes gently to 200 metres (110 fathoms) before falling away; the Falkland Islands being located two thirds of the way along this protrusion.[2]
The base of the plateau is about 100 metres (55 fathoms) below sea level to the west of the islands (400 km from the Patagonian coast), sloping to 200 metres (110 fathoms) to the east of the islands where it falls away into the South Atlantic Ocean. The Falklands Plateau, a slightly shallower stretch of water lies to the immediate east of the Falkland Islands.

To the immediate south of the islands, the Falklands Plateau is split into two by the Falklands Trough, an underwater valley that separates the plateau proper from the Scotia Arc - an underwater ridge that links Tierra Del Fuego with the Burwood Bank (where the water is only 20 metres (11 fathoms) deep) and, further into the Atlantic Ocean/Great Southern Ocean, with a number of islands including South Orkneys, South Sandwich Islands and South Georgia.[20]

Licences to harvest the large variety of fish that live on the shelf provides a major source of income for the islands as does the licensing of oil exploration.

Climate

Old text from here

Mainland UK and the Falkland Islands on the same scale and latitudes. The Falkland Islands have been inverted to allow both the 51°N and 51°S latitude lines and the 53°N and 53°S latitude lines to be lined up. The Falkland Islands are slightly smaller than Northern Ireland.

The Falkland Islands have a

diurnal temperature ranges and no marked wet and dry season while in the sub-arctic zone the average monthly maximum temperature exceeds 10 °C (50 °F) for no more than four months of the year and the average monthly minimum does not drop below −3 °C (27 °F).[21] The Falkland Islands climate is very much influenced by both the cool ocean currents and the shielding effect of the Andes
.

The cold Antarctic Coastal Current[22] flows in an easterly direction around Cape Horn where part of it is diverted northwards as the Falklands Current. Subsurface temperatures in the vicinity of the Falklands are of the order of 6°C. The Falklands Current meets the warm South Brazilian Current at about 40°S, some 1,000 km (620 mi) north of the islands.[23] The prevailing winds at the Falklands' latitude are the westerlies that gather moisture across the Pacific Ocean, but the Andes form a 4,000 m (13,000 ft) barrier causing a rain shadow across the Patagonia and to a lesser extent, the Falkland Islands.[24]

The January average maximum temperature is about 13°C (55°F), and the July maximum average temperature is about 4°C (39°F).[Note 1] The rainfall varies between 300 mm in parts of Lafonia to 1400 mm in the mountain ranges[25] with an average annual rainfall of 573 mm.[26] Humidity and winds, however, are constantly high. Snow is rare but can occur at almost any time of year. Gales are very frequent, particularly in winter.[27]

In addition to parts of the Falklands, a maritime subarctic climatic zone is found in parts of coastal Iceland, Faroe Islands, north western coastal Norway, southern islands of Alaska and parts of the Alaskan Panhandle, the southern tip of South America and mountainous areas of Europe including the Scottish Highlands and south-western Norway.[28]

Climate data for Stanley, Falkland Islands
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Record high °C (°F) 24
(75) 		23
(73) 		21
(70) 		17
(63) 		14
(57) 		11
(52) 		10
(50) 		11
(52) 		15
(59) 		18
(64) 		22
(72) 		22
(72) 		24
(75)
Mean daily maximum °C (°F) 13
(55) 		13
(55) 		12
(54) 		9
(48) 		7
(45) 		5
(41) 		4
(39) 		5
(41) 		7
(45) 		9
(48) 		11
(52) 		12
(54) 		9
(48)
Mean daily minimum °C (°F) 6
(43) 		5
(41) 		4
(39) 		3
(37) 		1
(34) 		−1
(30) 		−1
(30) 		−1
(30) 		1
(34) 		2
(36) 		3
(37) 		4
(39) 		2
(36)
Record low °C (°F) −1
(30) 		−1
(30) 		−3
(27) 		−6
(21) 		−7
(19) 		−11
(12) 		−9
(16) 		−11
(12) 		−11
(12) 		−6
(21) 		−3
(27) 		−2
(28) 		−11
(12)
Average precipitation mm (inches) 71
(2.8) 		58
(2.3) 		64
(2.5) 		66
(2.6) 		66
(2.6) 		53
(2.1) 		51
(2.0) 		51
(2.0) 		38
(1.5) 		41
(1.6) 		51
(2.0) 		71
(2.8) 		681
(26.8)
Average
relative humidity
(%) 		78 79 82 86 88 89 89 87 84 80 75 77 83
Source: BBC Weather[29]

Flora and Fauna

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Main article: Wildlife of the Falkland Islands

warrah, the loup-renard of Louis Antoine de Bougainville, a kind of fox found on both major islands that became extinct in the mid-19th century.[32][33][34][35] Slater suggests that the warrah was introduced into the Falkland Islands either by rafting or by dispersal of glacial ice during one of the glaciations of the late Pleistocene epoch (2.5 million and 15,000 years ago).[36]

A total of 14 species of

Magellanic Penguin breed on the islands as do over 60% of the global black-browed albatross population.[37][39]

Gypsy Cove

There are no native reptiles or amphibians on the islands. Over 200 species of insects have been recorded, along with 43 spider species and 12 worm species. Only 13 terrestrial invertebrates are recognised as endemic, although information on many species is lacking and it is suspected up to two thirds of species found are actually endemic. Due to the island environment, many insect species have developed reduced or absent wings. There are around 129 freshwater invertebrates, the majority being rotifer; however, the identification of some species remains in dispute.[19] Six species of fish are found in freshwater areas, including zebra trout and falklands minnows.[19]

The islands claim a territorial sea of 12 nautical miles (22 km) and an

exclusive fishing zone of 200 nautical miles (370 km), which has been a source of disagreement with Argentina. Different species of krill are found in Falkland waters, with Lobster Krill inhabiting the warmer waters in the north.[40] The waters around the Falkland Islands are part of the Patagonian Shelf Large Marine Environment. Fin fish that are harvested in the Falkland waters include southern blue whiting (Micromesistius australis), rock cod (Patagonotothen), hoki (Macruronus magellanicus) and the principal species of squid that are harvested are the Illex squid (Illex argentinus) and the Patagonian squid (Loligo gahi).[41] The squid spawn in the mouth of the Río de la Plata close to the confluence of the cold Falklands current and the warm Brazilian current, migrate southwards along the Patagonian Shelf into the Falklands waters and then return to their spawning grounds along that lies off the continental shelf.[42]

There are no native tree species on the archipelago, although two species of bushes,

Pale Maiden (Sisyrinchium jubatum) is the islands' national flower.[38]

Solifluction, the slow down-slope movement of soil and superficial debris, occurs in ground that is thawing after being frozen. In the Falkland Islands, it has led to the smoothing of slopes and the formation of stone-runs whilst leaving rock outcrops intact. Stone runs are an accumulation of boulders with no fine rock material and sparse vegetation and occur on slopes and in valley bottoms. They are a particularly distinctive component of the Falklands landscape and form a particularly sensitive niche environment.

Human Geography

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Prior to 1812, various colonial powers had small settlements on the Falklands Islands. In that year the islands were abandoned but within twenty years the British had re-established a settlement. In the 1851 census, the settlement's population was recorded as 287, increasing to 2043 in 1901 and 2563 in 2012.[43][Note 2]

Human settlements and activities

The main settlements in the islands are at

Falkland War, the settlements in Camp were connected by tracks that were often impassable in wet weather,.[46] but by 2007, the Falkland Islands had a road network of 786 kilometres (488 mi) with a further roads planned for construction link to all occupied mainland settlements by 2013.[47]

In the early nineteenth century, the main economic activity on the islands was seal hunting. Later the islands became a re-provisioning depot for clippers sailing from Australia to the United Kingdom via Cape Horn.

Over 80% of the island's land is given over to

perennial pasture. Roughly 40% of the national flock are on West Falkland and 60% on East Falkland.[48] In addition to dairy and pig farming. A small amount of reindeer farming is carried out, for example on the Beaver group of islands.[49] This herd was the only herd in the world that was unaffected by the Chernobyl disaster.[50]

In the last decade of the twentieth century and the early twenty-first century, tourism and fishing have made a major economic impact on the islands and as of 2012 an oil exploration industry was developing.

Impact of human activity

There is little long-term data on habitat changes, so the extent of human impact is unclear.

Grey foxes have been introduced and are having a detrimental impact on birds that nest on the shores, as are feral cats. 22 introduced plant species are thought to provide a significant threat to local flora.[19]

Notes

  1. southern hemisphere
    , January is the hottest month and July the coldest.
  2. ^ a b The census figures exclude military personnel and contract civilian staff based at the Mount Pleasant Garrison

References

  1. ^ "Patagonian Shelf large marine ecosystem". The encyclopaedia of Earth. 19 May 2008. Retrieved 31 October 2012.
  2. ^ a b Heileman (2009). "XVI-55 Patagonian Shelf: LME #14" (Document). United Nations EP. {{cite document}}: Unknown parameter |accessdate= ignored (help); Unknown parameter |fisrts1= ignored (help); Unknown parameter |url= ignored (help); Unknown parameter |work= ignored (help)
  3. ISBN 1 86107 534 0
    . Retrieved 31 October 2012.
  4. ^ Otley H, Munro G, Clausen A and Ingham B. (2008). "Falkland Islands - State of the Environment Report" (PDF). Falkland Islands Government and Falklands Conservation, Stanley. Retrieved 2010-06-05.{{cite web}}: CS1 maint: multiple names: authors list (link)
  5. ^ "The Islands: Location". Falkland Islands Government web site. 2007. Retrieved 8 April 2007.
  6. ^ a b BGS paper
  7. ^ a b c State of the Environment Report 2008
  8. ^ a b Johnston, S.T. (2000). "The Cape Fold Belt and Syntaxis and the rotated Falkland Islands: dextral transpressional tectonics along the southwest margin of Gondwana". Journal of African Earth Sciences. 31 (1). Elsevier Science Ltd.
  9. ISBN 978-1-85531-221-0
    . Retrieved 24 October 2012.
  10. ^ Admiralty Chart 2558 – Falkland Sound Northern Part (Map). 1:75000. Hydrographic Office. 2009.
  11. ^ Admiralty Chart 2559 – Falkland Sound Southern Part (Map). 1:75000. Hydrographic Office. 2009.
  12. ^ a b rise/inventory_report/inventory_report/at_download/file "Inventory of European data sources relevant for coastal erosion assessment in Europe (page 122)". European Commission. 2002. Retrieved 6 October 2012. {{cite web}}: Check |url= value (help)
  13. ^ Measured on Google Earth
  14. ^ a b Otley, H; Munro, G; Clausen, A; Ingham, B. "Falkland Islands State of the Environment Report 2008" (PDF) (Document). Stanley: Falkland Islands Government and Falklands Conservation. p. 16 - 18. {{cite document}}: Unknown parameter |accessdate= ignored (help)
  15. ^ a b Bingham, Mike (2002). "Flora and Fauna: General Information". Falklands.net. Retrieved 10 October 2012.
  16. ^ P Turnbull (2004-03-2-). "Falkland Islands". South Seas: South Seas Companion. Retrieved 5 March 2010. {{cite web}}: Check date values in: |date= (help)
  17. ^ "(Falkland Island) Location". The Falkland Islands Government. 2009. Retrieved 5 March 2010.
  18. ^ "Falklands.info Geography". web page. Retrieved 24 July 2010.
  19. ^ a b c d e f g h i Otley, Helen; Munro, Grant; Clausen, Andrea; Ingham, Becky (May 2008). "Falkland Islands State of the Environment Report 2008" (PDF). Environmental Planning Department Falkland Islands Government. Retrieved 25 March 2011.
  20. ^ "[[Scotia Arc]]". Encyclopædia Britannica. 2012. Retrieved 30 October 2012. {{cite encyclopedia}}: URL–wikilink conflict (help)
  21. ^ "Climate Zones: South America" (PDF). New York: Socioeconomic Data and Applications (SEDAC), Earth Institute, Columbia University. 2012. Retrieved 8 June 2012.
  22. ^ Gyory, Joanna; Cangialosi, John; Jo, Ieng; Mariano, Arthur J; Ryan, Edward H (2008). "Surface Currents in the Southern Ocean: The Antarctic Coastal Current". National Oceanographic Partnership Program. Retrieved 23 October 2012.
  23. ^ Gyory, Joanna; Mariano, Arthur J; Ryan, Edward H (2008). "Surface Currents in the Atlantic Ocean : The Malvinas Current". National Oceanographic Partnership Program. Retrieved 23 October 2012.
  24. ISBN 978-1-85531-221-0
    . Retrieved 24 October 2012.
  25. ^ McAdam, Jim (15 March 2012). "Climate Change in the Falkland Islands - A Project by the United Kingdom Falkland Islands Trust" (PDF). United Kingdom Falkland Islands Trust. Retrieved 14 June 2012.
  26. ^ "The Falkland Islands" (PDF). Falkland Islands Tourist Board. Retrieved 24 October 2012.
  27. British Broadcasting Corporation
    . 2007. Retrieved 15 March 2010.
  28. ^ "Common Expressions: Oceanic Climate". Webster's Online Dictionary. Retrieved 6 June 2012.
  29. ^ "BBC Weather: Stanley, Falkland Islands". BBC. Retrieved 13 January 2010.
  30. ^ Miklos D F Udvardy (1975). "A Classification of the Biogeographical Provinces of the World" (PDF). IUCN. pp. 37–38. Retrieved 25 March 2011.
  31. ^ C Barry Cox (2001). "The biogeographic regions reconsidered" (PDF). Journal of Biogeography. 28: 518. Retrieved 25 March 2011.[dead link]
  32. ^ a b "Geography". Falklands.info. Retrieved 24 July 2010.
  33. ^ Paddle, R. (2000). The Last Tasmanian Tiger. The history and extinction of the Thylacine. Cambridge, UK: Cambridge University Press. pp. 234–235.
  34. ^ Darwin, C.R. 1839. The zoology of the Voyage of H.M.S. Beagle. During the years 1832–1836. Part II. Mammalia. Smith Elder, London.
  35. ^ Slater, Graham J.; et, al (3 November 2009). "Evolutionary history of the Falklands wolf" (PDF). Current Biology. Vol 19 (20): 937–938. Retrieved 4 November 2012. {{cite journal}}: |volume= has extra text (help)
  36. ^ a b "Falklands factsheet" (PDF). Falkland Islands Tourist Board. Retrieved 25 March 2011.
  37. ^ a b c "Nature". Falkland Islands Government. Retrieved 25 March 2011.
  38. ^ C. Michael Hogan. 2008. Magellanic Penguin, GlobalTwitcher.com, ed. N. Stromberg
  39. ^ a b c d Mike Bingham. "Falklands/Falkland Islands". International Penguin Conservation Work Group. Retrieved 24 March 2011.
  40. ^ "Fisheries Department Fisheries Statistics, Volume 16, (2002 - 2011)" (PDF). Stanley, Falkland Islands: Falkland Islands Government. 2010. Retrieved 4 November 2012.
  41. ^ John Barton (18 April 2007). "The Offshore Fishery; balancing commercial activities & conservation". Falklands Fisheries. Retrieved 17 June 2010.
  42. ^ a b "Headline results of 2012 Falkland Islands Census released". Falkland Islands Government. 10 September 2012. Retrieved 2 November 2012.
  43. ^ Census figures
  44. ^ "Falkland Islands Census Statistics, 2006" (PDF). Falkland Islands Government. Retrieved 2 November 2010.
  45. ^ "Falkland Focus - News from the Falkland Islands Government" (PDF). July/August 2007. Retrieved 2010-12-29. {{cite web}}: Check date values in: |date= (help)
  46. ^ "Transport and Communication". Falkland Islands Government. Retrieved 2010-07-18.
  47. ^ "Biennial Report 2008/9" (PDF). Falklands Island Government Department of Agriculture. 31 May 2009. Retrieved 18 April 2010.
  48. ^ "FK002 - [[Beaver Island]] Group". BirdLife International. 2006. Retrieved 2 November 2012. {{cite web}}: URL–wikilink conflict (help)
  49. ^ a b "Falkland Islands (Islas Malvinas)". CIA. Retrieved 5 March 2010.
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