Mid-Atlantic RidgeMid-Atlantic Ridge

General introductionGeneral introductionto Mid-Atlantic Ridgeto Mid-Atlantic Ridge

The Mid-Atlantic Ridge (MAR) is a mid-ocean ridge, a divergent tectonic plate boundary located along the floor of the Atlantic Ocean, and part of the longest mountain range in the world. It separates the Eurasian Plate and North American Plate in the North Atlantic, and the African Plate from the South American Plate in the South Atlantic.

The Mid-Atlantic Ridge (MAR) is a mid-ocean ridge, a divergent tectonic plate boundary located along the floor of the Atlantic Ocean, and part of the longest mountain range in the world. It separates the Eurasian Plate and North American Plate in the North Atlantic, and the African Plate from the South American Plate in the South Atlantic.

The Mid-Atlantic Ridge is a huge underwater mountain range that runs from just 333 km (207 mi) south of the North Pole to Bouvet Island, located in the Atlantic ocean at a longitude just below South Africa. The Mid-Atlantic Ridge, about 10,000 km (6,200 mi) long, connects to a series of oceanic ridges that encircle the entire planet, with a total length of about 40,000 km (25,000 mi).

The Mid-Atlantic Ridge is a huge underwater mountain range that runs from just 333 km (207 mi) south of the North Pole to Bouvet Island, located in the Atlantic ocean at a longitude just below South Africa. The Mid-Atlantic Ridge, about 10,000 km (6,200 mi) long, connects to a series of oceanic ridges that encircle the entire planet, with a total length of about 40,000 km (25,000 mi).

Although the existence of the Mid-Atlantic Ridge was first inferred by Matthew Fontaine Maury in 1850, it was not discovered until 1872, when an expedition of the HMS Challenger discovered the ridge while scouting for a transatlantic telegraph cable. In 1925, a confirmation of the ridge, as well as additional details, were uncovered by sonar. It was found to be 300 to 600 miles wide, consisting of a parallel series of ridges increasing in height. The Mid-Atlantic Ridge is about two miles (3.2 km) above the sea floor, which has an average depth of three miles (4.8 km). The Mid-Atlantic Ridge serves to divide the Atlantic sea floor into two distinct basins.

Although the existence of the Mid-Atlantic Ridge was first inferred by Matthew Fontaine Maury in 1850, it was not discovered until 1872, when an expedition of the HMS Challenger discovered the ridge while scouting for a transatlantic telegraph cable. In 1925, a confirmation of the ridge, as well as additional details, were uncovered by sonar. It was found to be 300 to 600 miles wide, consisting of a parallel series of ridges increasing in height. The Mid-Atlantic Ridge is about two miles (3.2 km) above the sea floor, which has an average depth of three miles (4.8 km). The Mid-Atlantic Ridge serves to divide the Atlantic sea floor into two distinct basins.

THE FORMATIONTHE FORMATIONof Mid-Atlantic Ridgeof Mid-Atlantic Ridge

The divergent tectonic plate boundary

•This divergent boundary first formed in the Triassic period when a series of three-armed grabens coalesced on the supercontinent Pangaea to form the ridge. •Usually only two arms of any given three-armed graben become part of a divergent plate boundary. The failed arms are called aulacogens, and the aulacogens of the Mid-Atlantic Ridge eventually became many of the large river valleys seen along the Americas and Africa (including the Mississippi River, Amazon River and Niger River).

The separation of two continents• Approximately 20 million years

ago • Arica and South America • the surrounding water• about 5 centimeters per year • for the past 20 million years • What began as a small crack in

the Earth's crust is now the Mid-Atlantic Ridge, a giant undersea mountain range. As magma rises to escape along this ridge new crust is formed, sea-floors spread, and continents drift around the globe.

Spreading Rate• Measured in mm/yr Subdivisions >100 mm/yr, 100–55 mm/yr 55–20 mm/yr• Spreading rate of the

north Atlantic Ocean is ~ 25 mm/yr• In the Pacific region, it

is 80–120 mm/yr

Discoveryof Mid-Atlantic Ridge

• First inferred by M.F.

Maury in 1850• Discovered during the

Challenger expedition in 1872• Confirmed by sonar in

1925• Further discovery by

Bruce Heezen and Maurice Ewing in the 1950s

Impactsof Mid-Atlantic Ridge

“The Mid-Atlantic Ridge ... zone in which the floor of the Atlantic, as it keeps spreading, is continuously tearing open and making space for fresh, relatively fluid and hot sima [rising] from depth,” stated Alfred Wegener.

“The discovery of this worldwide ridge system led to the theory of seafloor spreading and general acceptance of Wegener's theory of continental drift and expansion as plate

tectonics.”

•Scientists mapped the Earth’s ocean floors in the 1950s.

•The ridge is a part of a continuous system of mid-ocean ridges on the floors of all the Earth’s oceans.

Iceland is on the MID-ATLANTIC RIDGE.

ICELAND

•Created by rifting, and accretion through volcanism

•Highly geologically active with more than 100 volcanoes

•The volcanic eruption of Laki in 1783–1784

ICELAND

•Widespread availability of geothermal power and the harnessing of many rivers and waterfalls for hydroelectricity

•Inexpensive hot water and home heat.(Highly attractive to tourists)

•Some cultural impacts to Iceland

TURBULENCE

•Seawater rushes through the narrow gullies.

•The turbulence stirs the almost freezing-water near the bottom with warmer water

•Great impact on climate

Animals in the sea

Provide shelters for different kinds of animals as a complete ecosystem.

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References• http://www.planetaryvisions.com/display.php?id=EBB_031&t=1&w=1 • http://wanderingtrader.com/2010/05/26/golden-circle-iceland/ • http://puzzlist.blogspot.com/2011_04_01_archive.html• http://www.crystalinks.com/mid-atlanticridge.html • http://www.wisegeek.com/what-is-the-mid-atlantic-ridge.htm • http://www.sonofthesouth.net/revolutionary-war/maps/old-map-world.htm• Hsü, Kenneth J. (1992) Challenger at Sea, Princeton, Princeton University Press, page 57• Redfern, R.; 2001: Origins, the Evolution of Continents, Oceans and Life, University of

Oklahoma Press, ISBN 1841881929, p. 26• Alexander Hellemans and Brian Bunch, 1989, Timeline of Science, Sidgwick and Jackson,

London• Edgar W. Spencer, 1977, Introduction to the Structure of the Earth, 2nd edition, McGraw-

Hill, Tokyo• http://thedispersalofdarwin.wordpress.com/2008/03/05/born-this-day-c-wyville-

thomson-naturalist-of-hms-challenger/• http://articles.nydailynews.com/2010-04-17/news/27062021_1_ash-spews-eruptions• http://www.whoi.edu/page.do?pid=30439&tid=441&cid=84868&ct=61&article=54452

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References• Jacoby, W. R. (January 1981). "Modern concepts of earth dynamics anticipated by Alfred

Wegener in 1912". Geology 9: 25–27. Bibcode 1981Geo.....9...25J. doi:10.1130/0091-7613(1981)9<25:MCOEDA>2.0.CO;2.

• "Geology of Iceland". Iceland.is. Retrieved 10 February 2010.• "Iceland". Jane Simmonds (1999). Langenscheidt. p.100. ISBN 0-88729-176-7• "Late Holocene climate". Academic.emporia.edu. Retrieved 2010-02-10.• http://www.standingstill.co.uk/peterthewildboy/1783-icelandic-eruption-devastates-

georgian-england• http://www.fark.com/comments/5185397/Bjecause-of-bjanking-economic-bjreakdown-

residents-of-Iceland-are-now-leaving-their-country-in-bjunches• http://iceland.vefur.is/iceland_nature/geology_of_iceland/index.htm• http://www.science20.com/news/

mid_atlantic_ridge_turbulence_has_big_impact_on_climate• http://www.wallpaper23.com/full.asp?ID=1980&R=1440x900

Thank you