is a steep slope
or long cliff
that forms as a result of faulting
and separates two relatively level areas having different elevations
. The terms scarp
and scarp face
are often used interchangeably with escarpment
Some sources differentiate the two terms, with escarpment
referring to the margin between two landforms
, and scarp
referring to a cliff or a steep slope.
In this usage an escarpment is a ridge which has a gentle slope on one side and a steep scarp on the other side.
More loosely, the term scarp
also describes a zone between a coastal lowland
and a continental plateau
which shows a marked, abrupt change in elevation
caused by coastal erosion
at the base of the plateau.
Formation and description
Scarps are generally formed by one of two processes: either by differential erosion
of sedimentary rocks
, or by movement of the Earth's crust
at a geologic fault
. The first is the more common type: the escarpment is a transition from one series of sedimentary rocks
to another series of a different age and composition. Escarpments are also frequently formed by faults. When a fault displaces the ground surface so that one side is higher than the other, a fault scarp
is created. This can occur in dip-slip faults
, or when a strike-slip fault
brings a piece of high ground adjacent to an area of lower ground.
Schematic cross section of a cuesta
, dip slopes facing left, and harder rocklayers in darker colors than softer ones
is not the only planet where escarpments occur. They are believed to occur on other planets when the crust contracts
, as a result of cooling. On other Solar System
bodies such as Mercury
, and the Moon
, the Latin term rupes
is used for an escarpment.
When sedimentary beds are tilted and exposed to the surface, erosion
may occur. Escarpments erode gradually and over geological time
. The mélange
tendencies of escarpments results in varying contacts between a multitude of rock types. These different rock types weather at different speeds, according to Goldich dissolution series
so different stages of deformation can often be seen in the layers where the escarpments have been exposed to the elements.
Australia and New Zealand
At the Florida Escarpment
, seen in the eastern Gulf of Mexico, the sea bed drops precipitously from less than 300 to 3,000 m (1,000 to 10,000 ft) over a short distance.
- Florida Escarpment, Gulf of Mexico
- Sigsbee Escarpment, Gulf of Mexico
- Canada and the United States
- Manitoba Escarpment (Manitoba, Saskatchewan)
- Pembina Escarpment (Manitoba, North Dakota)
- Niagara Escarpment ((east to west) New York, Ontario, Michigan, Wisconsin, and Illinois)
- Eardley Escarpment (Mattawa Fault, Gatineau Park, Quebec)
- Onondaga (geological formation) (Ontario and New York)
- Devil's Rock (Lake Temiskaming, Ontario)
- Scarborough Bluffs (Toronto, Ontario)
- United States
- The Caribbean
West Andean Escarpment
- ^ Easterbrook, Don J. (1999). Surface Processes and Landforms. Prentice Hall. ISBN 978-0-13-860958-0.[page needed]
- ^ Summary: Escarpments, US Army Corps of Engineers.
- ^ "Scarps and Terraces". Physiography. Radford University. Retrieved 24 December 2020.
- ^ Lidmar-Bergström, Karna (1988). "Denudation surfaces of a shield area in southern Sweden". Geografiska Annaler. 70 A (4): 337–350. doi:10.2307/521267. JSTOR 521267.
- ^ Wörner, Gerhard; Uhlig, Dieter; Kohler, Ingrid; Seyfried, Hartmut (15 February 2002). "Evolution of the West Andean Escarpment at 18°S (N. Chile) during the last 25 Ma: uplift, erosion and collapse through time". Tectonophysics. 345 (1): 183–198. doi:10.1016/S0040-1951(01)00212-8.
Last edited on 12 May 2021, at 04:40
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