Đụn cát

Erg Chebbi, Morocco

Đụn cát Maspalomas ở Gran Canaria

Vết trượt lở trên đỉnh của đụn cát Kelso, khu bảo tồn quốc gia Mojave, California.

Trong địa lý tự nhiên, đụn cát (hoặc cồn cát) là một đồi cát kết quả từ quá trình trầm tích gió (aeolian processes). Đụn cát có nhiều hình dạng và kích thước khác nhau, hình thành do tương tác giữa gió với gió. 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. The valley or trough between dunes is called a slack. A "dune field" is an area covered by extensive sand dunes. Large dune fields are known as ergs.

Some coastal areas have one or more sets of dunes running parallel to the shoreline directly inland from the beach. In most cases the dunes are important in protecting the land against potential ravages by storm waves from the sea. Although the most widely distributed dunes are those associated with coastal regions, the largest complexes of dunes are found inland in dry regions and associated with ancient lake or sea beds.

Dunes also form under the action of water flow (alluvial processes), on sand or gravel beds of rivers, estuaries and the sea-bed.

The modern word "dune" came into English from French circa 1790. In ancient times, words cognate to "dune" probably had the meaning of a built-up hill or citadel fortification.

Tham khảo

• Ralph Bagnold The Physics of Blown Sand (1941)
• “Nouakchott, Mauritania”. NASA Earth Observatory. Truy cập 28 Tháng tư năm 2006.
• V. Badescu, R. B. Cathcart and A. A. Bolonkin, "Sand Dune Fixation: a solar-powered Sahara seawater pipeline macroproject", in: Land Degradation & Development; 19, (2008): doi: 10.1002/ldr.864.
• “Types of Dunes”. USGS. Truy cập 6 tháng Mười năm 2010.
• “Summary: Dunes, Parabolic”. Desert Processes Working Group; Knowledge Sciences, Inc. Truy cập 6 tháng Mười năm 2010.

Liên kết ngoài

• Coastal Sand Dunes
• Magilligan Dunes, Northern Ireland
• Dune pattern identification, U.S. Army
• Treading Lightly: Minimum Impact Dune Hiking
• Dune Racers of the Empty Quarter – video of sand dunes in the United Arab Emirates
• The Bibliography of Aeolian Research
• Sahara sand dunes forms – as investigated by native offroaders from Egypt
• Gold Coast Dune Management Policy
• USGS page on dune types
• Great Sand Dunes National Park