A dip slope is a topographic or

geomorphic Geomorphology () is the scientific study of the origin and evolution of topography, topographic and bathymetry, bathymetric features generated by physical, chemical or biological processes operating at or near Earth#Surface, Earth's surface. Ge ...

surface which slopes in the same direction, and often by the same angle, as the true dip or apparent dip of the underlying

strata In geology and related fields, a stratum (: strata) is a layer of Rock (geology), rock or sediment characterized by certain Lithology, lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by v ...

.Jackson, JA, J Mehl and K Neuendorf (2005) ''Glossary of Geology.'' American Geological Institute, Alexandria, Virginia. 800 pp. Allaby, M (2008) ''A Dictionary of Earth Science.'' Oxford University Press, New York, New York. 654 pp. A dip slope consists of the upper surface of a resistant layer of rock, often called ''

caprock Caprock or cap rock is a hard, resistant, and impermeable layer of rock that overlies and protects a reservoir of softer organic material, similar to the crust on a pie where the crust (caprock) prevents leakage of the soft filling (softer materia ...

'', that is commonly only slightly lowered and reduced in steepness by

erosion Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, tran ...

. Dip slopes form the backslopes of

cuesta A cuesta () is a hill or ridge with a gentle slope on one side, and a steep slope on the other. In geology, the term is more specifically applied to a ridge where a harder sedimentary rock overlies a softer layer, the whole being tilted somew ...

homoclinal ridge A homoclinal ridge or strike ridge is a hill or ridge with a moderate, generally between 10° and 30°, sloping backslope. Its backslope is a '' dip slope,'' that conforms with the dip of a resistant stratum or strata, called '' caprock.'' On the ...

s, hogbacks, and flatirons. The frontslopes of such ridges consist of either an

escarpment An escarpment is a steep slope or long cliff that forms as a result of faulting or erosion and separates two relatively level areas having different elevations. Due to the similarity, the term '' scarp'' may mistakenly be incorrectly used inte ...

, a steep slope, or perhaps even a line of

cliff In geography and geology, a cliff or rock face is an area of Rock (geology), rock which has a general angle defined by the vertical, or nearly vertical. Cliffs are formed by the processes of weathering and erosion, with the effect of gravity. ...

s. Generally, cuestas and homoclinal ridges are asymmetrical in that their dip slopes are less steep than their escarpments. In the case of hogbacks and flatirons, the dip of the rocks is so steep that their dip slope approaches the escarpment in their steepness.Cotton, CA (1952) ''Geomorphology An Introduction to the Study of Landforms, 6th ed.'' John Wiley and Sons, New York. 505 pp.Fairbridge, RW (1968) ''Hogback and Flatiron.'' In RW Fairbridge, ed., pp. 524-525, ''The Encyclopedia of Geomorphology'' (Encyclopedia of Earth Sciences, Volume III), Reinhold, New York, 1296 pp. Simonett, SD (1968) ''Cuesta.'' In RW Fairbridge, ed., pp. 233, ''The Encyclopedia of Geomorphology'' (Encyclopedia of Earth Sciences, Volume III), Reinhold, New York, 1296 pp. MountRundle

Dip slopes are the result of the differential erosion of strata of varying resistance to erosion that are dipping uniformly in one direction. In this case, strata, i.e.

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny f ...

mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from ''shale'' by its lack of fissility.Blatt, H., and R.J. Tracy, 1996, ''Petrology.'' New York, New York, ...

, and

marl Marl is an earthy material rich in carbonate minerals, Clay minerals, clays, and silt. When Lithification, hardened into rock, this becomes marlstone. It is formed in marine or freshwater environments, often through the activities of algae. M ...

, that are less resistant to erosion are preferentially eroded relative to stronger strata, i.e.

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

, and dolomite, that are more resistant to erosion. As a result, the less resistant strata will be eroded away leaving the more resistant strata as a caprock forming the dip slope (backslope) of a ridge that slopes in the direction of caprock. When this happens to flat-lying beds, landforms such as

plateau In geology and physical geography, a plateau (; ; : plateaus or plateaux), also called a high plain or a tableland, is an area of a highland consisting of flat terrain that is raised sharply above the surrounding area on at least one side. ...

mesa A mesa is an isolated, flat-topped elevation, ridge, or hill, bounded from all sides by steep escarpments and standing distinctly above a surrounding plain. Mesas consist of flat-lying soft sedimentary rocks, such as shales, capped by a ...

s, and

butte In geomorphology, a butte ( ) is an isolated hill with steep, often vertical sides and a small, relatively flat top; buttes are smaller landforms than mesas, plateaus, and table (landform), tablelands. The word ''butte'' comes from the French l ...

s are formed. The erosion of tilted beds will form landforms called cuestas, homoclinal ridges, hogbacks, and flatirons. Plateaus, mesas, and buttes have flat tops, while cuestas and homoclinal ridges are asymmetrical (~flat) areas w/ridges. The less steep side (at the low point) is their dip slope (intersecting 'ground' surface, and disappearing underground) and the steeper other side (the opposite, and at the high point) is their escarpment. In case of hogbacks, the steepness of the dip slope and

will be about the same. Dip slopes can also be formed by

igneous Igneous rock ( ), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rocks are formed through the cooling and solidification of magma or lava. The magma can be derived from partial ...

structures such as sills.

Landslides

Some dip slopes are quite prone to

landslide Landslides, also known as landslips, rockslips or rockslides, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, mudflows, shallow or deep-seated slope failures and debris flows. Landslides ...

s, due to the dipping strata that underlie them. Large sheets of rock have a tendency to slide down dip slopes.

References

{{reflist Geomorphology Structural geology Slope landforms Erosion landforms

Landslides

See also

References