Bank (topography)

A bank is a shoal—a comparatively shallow area or an underwater hill on the continental shelf—surrounded by deeper water. It may be of volcanic nature. Banks may be carbonate or terrigenous. As they are not associated with any landmass, banks have no outside source of sediments. Carbonate banks are typically platforms, rising from the ocean depths, whereas terrigenous banks are elevated sedimentary deposits. [Morelock, J. (2005). [http://geology.uprm.edu/Morelock/marg.htm Morphology] . Geological Oceanography Program, University of Puerto Rico at Mayagüez (UPRM). Retrieved on: October 11, 2008.]

Seamounts, by contrast, are mountains, of volcanic origin, rising from the deep sea, and are steeper, and higher in comparison to the surrounding seabed.Farallones Marine Sanctuary Association. [http://www.farallones.org/findings/documents/Geology.pdf Islands, Banks & Seamounts: Geologic Features Under the Sea] .] Examples are Pioneer and Guide Seamounts, west of the Farallon Islands. The Pioneer Seamount has a depth of 1,000 meters, In other cases, parts of a bank may reach above the water surface, thereby forming islands. [World Wildlife Fund. [http://www.panda.org/about_wwf/what_we_do/marine/blue_planet/deep_sea/seamounts/index.cfm Deep sea ecology: seamounts] . Retrieved on: October 11, 2008.]

The largest banks in the world are:
# Grand Banks of Newfoundland (280,000 km²) [Fisheries and Oceans Canada [http://www.dfo-mpo.gc.ca/overfishing-surpeche/media/bk_grandbanks_e.htm Backgrounder: The Grand Banks and the Flemish Cap] . Retrieved on: October 11, 2008.] - terrigenous bank
# Great Bahamas Bank (95,798.12 km², has islands, area without islands)
# Saya de Malha (35,000 km², excluding the separate North bank, least depth 7 m)
# Seychelles Bank (31,000 km², including islands of 266 km²)
# Georges Bank (28,800 km²) - terrigenous bank
# Lansdowne Bank (21,000 km², west of New Caledonia, least depth 3.7 m)
# Dogger Bank (17,600 km², least depth 13 m)
# Little Bahamas Bank (14,260.64 km², has islands, area without islands)
# Great Chagos Bank (12,642 km², including islands of 4.5 km²)
# Reed Bank, Spratly Islands (8,866 km², least depth 9 m)
# Caicos Bank, Caicos Islands (7,680 km², including islands of 589.5 km²)
# Macclesfield Bank (6,448 km², least depth 9.2 m)
# North Bank or Ritchie Bank (5,800 km², north of Saya de Malha, least depth <10 m)
# Cay Sal Bank (5,226.73 km², including islands of 14,87 km²)
# Rosalind Bank (4,500 km², lest depth 7.3 m)Some of these banks may be sunken atolls.

Notes

External links

* [http://www.farallones.org/findings/documents/Geology.pdf definition]