Sand Dune Patterns Are Fractals
by Owen Borville
September 21, 2021
Science
Sand dune patterns showcase fractals in nature, or repeating patterns that extend infinitely. From large dunes to small, thin cross beds, these patterns are seen across the Earth as a result of water and wind erosion. Specifically, creationists believe the Flood of Genesis had a major role in the appearance of sand deposits and sand dune occurrence.
Types of sand dunes include:
Dune Types
A sand dune is a hill or ridge of sand forming where environmental conditions provide sand, steady wind and a location for the sand to collect. Dunes may occur in both coastal and more inland settings. Dunes migrate in the direction of the wind. Ergs are sand seas or regions covered by sand dunes. A draa is a large dune formed in the desert. Barchan dunes are the simplest and the most well-known dune. The barchan dune is a crescent-shaped dune usually located in desert climates. The arms or horns of the dune point downwind, and move faster than the center of the dune.
Longitudinal or sief dunes are long, straight, or slightly sinuous sand ridges that can be more than 160 kilometers long and may occur as isolated ridges. However, longitudinal dunes generally form sets of parallel ridges separated by miles of sand, gravel, or rocky inter-dune corridors. Some longitudinal dunes merge to form Y-shaped compound dunes. Many longitudinal dunes form in bidirectional wind regimes. The long axes of these dunes extend in the resultant direction of sand movement.
Barchanoid dunes are wave-like dunes that form from barchan dunes when more sand becomes available. When sand continues to accumulate, the barchanoid dunes grade into transverse dunes.
Transverse dunes are forward marching ridges that form when barchan dunes become aligned together along a plane perpendicular to the wind and the dunes becomes relatively straight.
Parabolic dunes occur in sandy vegetated areas when strong winds erode a section of the vegetated sand (commonly referred to as a blowout). Downwind motion occurs if sand from the blowout is deposited on the opposite slope of the parabolic dune and vegetation holds the arms of the dune in place as the windward nose of the dune migrates forward toward the main dune field.
Star dunes are star-shaped dunes which form in basin confined dune fields that experience seasonal variations in wind patterns. Opposing crosswinds cause the sand to pile up with one dune typically rising high above other dunes in a field. Some of the tallest sand dunes in the world are star dunes.
by Owen Borville
September 21, 2021
Science
Sand dune patterns showcase fractals in nature, or repeating patterns that extend infinitely. From large dunes to small, thin cross beds, these patterns are seen across the Earth as a result of water and wind erosion. Specifically, creationists believe the Flood of Genesis had a major role in the appearance of sand deposits and sand dune occurrence.
Types of sand dunes include:
Dune Types
A sand dune is a hill or ridge of sand forming where environmental conditions provide sand, steady wind and a location for the sand to collect. Dunes may occur in both coastal and more inland settings. Dunes migrate in the direction of the wind. Ergs are sand seas or regions covered by sand dunes. A draa is a large dune formed in the desert. Barchan dunes are the simplest and the most well-known dune. The barchan dune is a crescent-shaped dune usually located in desert climates. The arms or horns of the dune point downwind, and move faster than the center of the dune.
Longitudinal or sief dunes are long, straight, or slightly sinuous sand ridges that can be more than 160 kilometers long and may occur as isolated ridges. However, longitudinal dunes generally form sets of parallel ridges separated by miles of sand, gravel, or rocky inter-dune corridors. Some longitudinal dunes merge to form Y-shaped compound dunes. Many longitudinal dunes form in bidirectional wind regimes. The long axes of these dunes extend in the resultant direction of sand movement.
Barchanoid dunes are wave-like dunes that form from barchan dunes when more sand becomes available. When sand continues to accumulate, the barchanoid dunes grade into transverse dunes.
Transverse dunes are forward marching ridges that form when barchan dunes become aligned together along a plane perpendicular to the wind and the dunes becomes relatively straight.
Parabolic dunes occur in sandy vegetated areas when strong winds erode a section of the vegetated sand (commonly referred to as a blowout). Downwind motion occurs if sand from the blowout is deposited on the opposite slope of the parabolic dune and vegetation holds the arms of the dune in place as the windward nose of the dune migrates forward toward the main dune field.
Star dunes are star-shaped dunes which form in basin confined dune fields that experience seasonal variations in wind patterns. Opposing crosswinds cause the sand to pile up with one dune typically rising high above other dunes in a field. Some of the tallest sand dunes in the world are star dunes.
