Eolianite or aeolianite is any rock formed by the lithification of sediment

Sediment

Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....

 deposited by aeolian processes; that is, the wind

Wind

Wind is the flow of gases on a large scale. On Earth, wind consists of the bulk movement of air. In outer space, solar wind is the movement of gases or charged particles from the sun through space, while planetary wind is the outgassing of light chemical elements from a planet's atmosphere into space...

. In common use, however, the term refers specifically to the most common form of eolianite: coastal limestone

Limestone

Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....

 consisting of carbonate

Carbonate

In chemistry, a carbonate is a salt of carbonic acid, characterized by the presence of the carbonate ion, . The name may also mean an ester of carbonic acid, an organic compound containing the carbonate group C2....

 sediment of shallow marine

Marine (ocean)

Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...

 biogenic origin, formed into coastal dunes by the wind, and subsequently lithified. It is also known as kurkar in the Middle East

Middle East

The Middle East is a region that encompasses Western Asia and Northern Africa. It is often used as a synonym for Near East, in opposition to Far East...

, miliolite in India

India

India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

 and Arabia, and grès dunaire in the eastern Mediterranean.

They are understood to have formed during the last one million years, and it is thought that the timing of deposition is related to sea level, but the nature of that relationship remains the subject of some debate.

Eolianite occurs in many parts of the world. It occurs most extensively between the latitudes of 20° and 40° in both hemispheres, with little nearer the equator, and virtually no deposits nearer the poles. There is no apparent difference in distribution between the hemispheres, but if the extent and thickness of deposits are taken into account, the Southern Hemisphere

Southern Hemisphere

The Southern Hemisphere is the part of Earth that lies south of the equator. The word hemisphere literally means 'half ball' or "half sphere"...

 has the bulk of eolianite.

Conditions favourable for formation of eolianite are:

• a warm climate, favourable to the production of carbonate
  Carbonate
  In chemistry, a carbonate is a salt of carbonic acid, characterized by the presence of the carbonate ion, . The name may also mean an ester of carbonic acid, an organic compound containing the carbonate group C2....
  
   by shallow marine animals; for example, the production of seashell
  Seashell
  A seashell or sea shell, also known simply as a shell, is a hard, protective outer layer created by an animal that lives in the sea. The shell is part of the body of the animal. Empty seashells are often found washed up on beaches by beachcombers...
  
  s by marine molluscs;
• onshore winds to form beached sediment into dunes
  Dune
  In physical geography, a dune is a hill of sand built by wind. Dunes occur in different forms and sizes, formed by interaction with the wind. Most kinds of dunes are longer on the windward side where the sand is pushed up the dune and have a shorter "slip face" in the lee of the wind...
  
  ;
• a relatively low onshore topography, rather than onshore cliffs, to allow the formation of dune
  Dune
  In physical geography, a dune is a hill of sand built by wind. Dunes occur in different forms and sizes, formed by interaction with the wind. Most kinds of dunes are longer on the windward side where the sand is pushed up the dune and have a shorter "slip face" in the lee of the wind...
  
   systems;
• relatively low onshore rainfall, to promote rapid lithification;
• tectonic stability;

The most extensive deposits of eolianite in the world are located on the southern and western coasts of Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

. On the west coast, there are over 800 kilometres (497.1 mi) of eolianite cliffs, which are over 150 metres thick in some places. These cliffs, locally known as the Tamala Limestone

Tamala Limestone

Tamala Limestone is the geological name given to the widely occurring eolianite limestone deposits on the western coastline of Western Australia, between Shark Bay in the north and nearly to Albany in the south...

 Formation, contain layers of dune origin interspersed with layers of shallow-marine origin. Other substantial deposits occur in Bermuda

Bermuda

Bermuda is a British overseas territory in the North Atlantic Ocean. Located off the east coast of the United States, its nearest landmass is Cape Hatteras, North Carolina, about to the west-northwest. It is about south of Halifax, Nova Scotia, Canada, and northeast of Miami, Florida...

, the Bahamas, the southern and eastern coasts of South Africa

South Africa

The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

, the Mediterranean, India

India

India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

, and oceanic islands of the Pacific

Pacific Ocean

The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

, Atlantic

Atlantic Ocean

The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...

 and Indian

Indian Ocean

The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...

Oceans.

External links

• The Bibliography of Aeolian Research