FACTOID # 10: The total number of state executions in 2005 was 60: 19 in Texas and 41 elsewhere. The racial split was 19 Black and 41 White.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
   
 
WHAT'S NEW
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Abyssal plain

Abyssal plains are flat or very gently sloping areas of the deep ocean basin floor. They are among the Earth's flattest and smoothest regions and the least explored. Abyssal plains cover approximately 40% of the ocean floor and reach depths between 2,200 and 5,500 m (7,200 and 18,000 ft). They generally lay between the foot of a continental rise and a mid-oceanic ridge. Image File history File links Question_book-3. ... The abyssal zone contains the very deep benthic communities near the bottom of oceans. ... Animated map exhibiting the worlds oceanic waters. ...  Sediment  Rock  Mantle  The global continental shelf, highlighted in cyan The continental shelf is the extended perimeter of each continent, which is covered during interglacial periods such as the current epoch by relatively shallow seas (known as shelf seas) and gulfs. ... Courtesy USGS The Mid-Atlantic Ridge is an underwater mountain range of the Atlantic Ocean that runs from Iceland to Antarctica, and is the longest mountain range on Earth. ...


The abyssal plain is formed when the lower crust (sima), melted and pushed up by the up-welling mantle, reaches the surface at mid-ocean ridges and forms new oceanic crust. This new oceanic crust is mostly basalt and has a rugged topography. The roughness of this topography is a function of the rate at which the mid-ocean ridge is spreading (the spreading rate). Magnitudes of spreading rates vary quite significantly, and are generally broken down into 3 rates (fast, medium and slow). Typical values for fast-spreading ridges are >100 mm/yr, whilst medium-spreading rates are ~60 mm/yr, and slow-spreading ridges are typically <20 mm/yr. Studies have shown that the slower the spreading rate, the rougher the new oceanic crust will be, and vice versa. It is thought this is due to faulting at the mid-ocean ridge when the new oceanic crust was formed. This oceanic crust eventually becomes overlain with sediments, producing the flat appearance. Sima is the name for the lower layer of the Earths crust. ... For the cities, see Basalt, Colorado and Basalt, Idaho. ... For discussion of land surfaces themselves, see Terrain. ... Age of oceanic crust. ...


Abyssal plains result from the blanketing of an originally uneven surface of oceanic crust by fine-grained sediments, mainly clay and silt. Much of this sediment is deposited from turbidity currents that have been channeled from the continental margins along submarine canyons down into deeper water. The remainder of the sediment comprises chiefly dust (clay particles) blown out to sea from land, and the remains of small marine plants and animals (the plankton), which sink from the upper layer of the ocean, known as Pelagic sediment. The sediment deposition rate in remote areas is estimated at two to three centimetres per thousand years. In some areas of the plains manganese nodules are common with significant varying concentrations of metals, including iron, nickel, cobalt, and copper. These nodules may provide a significant resource for future mining ventures. Age of oceanic crust Oceanic crust is the part of Earths lithosphere that surfaces in the ocean basins. ... This article or section cites very few or no references or sources. ... For other uses, see Clay (disambiguation). ... For other uses, see Silt (disambiguation). ... A turbidity current or density current is a current of of rapidly moving, sediment-laden water moving down a slope through air, water, or another fluid. ... A Submarine canyon is a steep-sided valley on the seafloor of the continental slope. ... For the SpongeBob SquarePants character, see Plankton (SpongeBob SquarePants). ... Polymetallic nodules, also called manganese nodules, are rock concretions on the sea bottom formed of concentric layers of iron and manganese hydroxides around a core. ... For other uses, see Iron (disambiguation). ... For other uses, see Nickel (disambiguation). ... For other uses, see Cobalt (disambiguation). ... For other uses, see Copper (disambiguation). ...


Sediment covered abyssal plains are less common in the Pacific than in other major ocean basins because sediments from turbidity currents are trapped in submarine trenches that border the Pacific Ocean. For other meanings of Pacific, see Pacific (disambiguation). ... Categories: Stub | Plate tectonics | Earth sciences | Landforms | Oceanic trenches ...


This deep seafloor, between 4 and 6 km under the surface, is without comparison the largest habitat on earth, covering 60% of the earth's surface.

Contents

List of Abyssal Plains

Atlantic Ocean

  • Labrador Plain
  • Irminger Plain
  • Iceland Plain
  • Norwegian Plain
  • Cape Verde Plain
  • Sierra Leone Plain
  • Guinea Plain
  • Angola Plain
  • Cape Plain
  • Argentine Plain
  • Brasil Plain
  • Guayana Plain
  • Mexico Plain

Indian Ocean

  • Agulhas Plain
  • Natal Plain
  • Madagaskar Plain
  • Somalian Plain!
  • Runescape Plain
  • Middle-Indian Plain
  • Andamanian Plain
  • Wharton Plain
  • Perth's Plain
  • Crozet's Plain
  • Atlantic-Indian Plain
  • North Australian Plain
  • South Australian Plain

Pacific Ocean

  • Ceebes' Plain
  • South Chinese Plain
  • West Carolinian Plain
  • East Carolinian Plain
  • Coral sea Plain
  • Tasmani Plain
  • Southern Fiji Plain
  • Northern Fiji Plain
  • Melanesian Plain
  • East Mariana Plain
  • Northwestern Pacific Plain
  • Japanese Plain
  • Kurillian Plain
  • Middle Pacific Plain
  • Southwestern Pacific Plain
  • Southeastern Pacific Plain
  • Chile Plain
  • Peru Plain
  • Guatemala Plain

  Results from FactBites:
 
abyssal plain: Definition and Much More from Answers.com (592 words)
Abyssal plains cover approximately 40% of the ocean floor and reach depths between 2,200 and 5,500 m (7,200 and 18,000 ft).
The abyssal plain is formed when the lower crust (sima), melted and pushed up by the up-welling mantle, reaches the surface at mid-ocean ridges and forms new oceanic crust.
Abyssal plains result from the blanketing of an originally uneven surface of oceanic crust by fine-grained sediments, mainly clay and silt.
  More results at FactBites »

 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m