A homoclinal ridge or strike ridge is a

hill A hill is a landform that extends above the surrounding terrain. It often has a distinct Summit (topography), summit. Terminology The distinction between a hill and a mountain is unclear and largely subjective, but a hill is universally con ...

ridge A ridge or a mountain ridge is a geographical feature consisting of a chain of mountains or hills that form a continuous elevated crest for an extended distance. The sides of the ridge slope away from the narrow top on either side. The line ...

with a moderate, generally between 10° to 30°, sloping backslope. Its backslope is a ''

dip slope A dip slope is a topographic (geomorphic) surface which slopes in the same direction, and often by the same amount, as the true dip or apparent dip of the underlying strata.Jackson, JA, J Mehl and K Neuendorf (2005) ''Glossary of Geology.'' Ame ...

,'' that conforms with the dip of a resistant

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

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

, called ''

caprock Caprock or cap rock is a more resistant rock type overlying a less resistant rock type,Kearey, Philip (2001). ''Dictionary of Geology'', 2nd ed., Penguin Reference, London, New York, etc., p. 41.. . analogous to an upper crust on a cake that is har ...

.'' On the other side of the other slope, which is its frontslope, of a homoclinal ridge is a steeper or even cliff-like frontslope (

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. The terms ''scarp'' and ''scarp face'' are often used interchangeably with ''escar ...

) that is formed by the outcrop of the caprock. The escarpment cuts through the dipping strata that comprises the homoclinal ridge. Cotton, C.A. (1952) ''Geomorphology An Introduction to the Study of Landforms.'' John Wiley and Sons, New York. 505 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. Huggett, JR (2011) ''Fundamentals of Geomorphology,'' 3rd ed., Routledge, New York. 516 pp. Twidale, C.R. and E.M. Campbell (1993) ''Australian Landforms: Structure, Process and Time.'' Gleneagles Publishing, Adelaide, South Australia, Australia. 568 pp. Hogback ridges in Colorado

Homoclinal ridges are the expression of regional outcrops of moderately dipping

, typically

sedimentary Sedimentary rocks are types of rock (geology), rock that are formed by the accumulation or deposition of mineral or organic matter, organic particles at Earth#Surface, Earth's surface, followed by cementation (geology), cementation. Sedimentati ...

strata, that consist of alternating beds of hard, well-lithified strata, i.e.

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) ...

and

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

and weak or loosely cemented strata, i.e.

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especial ...

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 (parallel layering).Blatt, H., and R.J. Tracy, 1996, ''Petrology. ...

, and

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

. The surface of hard, erosion-resistant rock strata forms the caprock of the backslope (dip-slope) of the homoclinal ridges from which erosion has preferentially stripped any weaker strata. The opposite slope, its frontslope, that forms the front of a homoclinal ridge consists of an escarpment that cuts across the

bedding Bedding, also known as bedclothes or bed linen, is the materials laid above the mattress of a bed for hygiene, warmth, protection of the mattress, and decorative effect. Bedding is the removable and washable portion of a human sleeping environm ...

of the strata comprising it. Because of the moderately dipping nature of the strata that forms a homoclinal ridge, a significant shift in horizontal location will take place the landscape is lowered by

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...

.Thornbury, W. D., 1954, "Principles of Geomorphology'' New York, John Wiley & Sons, 618 pp. Because the slope of a homoclinal ridge dips in the same direction as the sedimentary strata underlying it, the dip angle of this bedding (Ө) can be calculated by v/h= tan(Ө) where v is equal to the vertical distance and h is equal to the horizontal distance perpendicular to the strike of the beds.Easterbrook, DJ (1999) ''Surface Processes and Landforms'', 2nd ed. Prentice-Hall, Inc, Upper Saddle River, New Jersey.

Cuesta A cuesta (from Spanish ''cuesta'' "slope") 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 ...

s, homoclinal ridges, and hogbacks comprise a sequence of landforms that form a gradational continuum. These landform differ only on the steepness of their backslopes and relative differences in the inclination of their backslopes and frontslopes. These differences depends upon whether the dip of the strata from which they have been eroded are either nearly vertical, moderately dipping, or gently dipping. In general, homoclinal ridges, or strike ridges, are associated with strata that dip between 10° and 30°. The symmetrical ridges that characterize hogbacks develop where the strata dip very steeply at 40° or more. Because they are gradational in nature, the exact angle of the backslope used to define these landforms is arbitrary and can vary in the scientific literature.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.

References

{{reflist Geomorphology Structural geology Slope landforms Erosion landforms Ridges