A rock shelter (also rockhouse, crepuscular cave, bluff shelter, or abri) is a shallow

cave A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word ''cave'' can refer to smaller openings such as sea ...

-like opening at the base of a bluff or

cliff In geography and geology, a cliff is an area of 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. Cliffs are common on co ...

. In contrast to

solutional cave A solutional cave, solution cave, or karst cave is a cave usually formed in the soluble rock limestone. It is the most frequently occurring type of cave. It can also form in other rocks, including chalk, dolomite, marble, salt beds, and gypsum. ...

s ( karst), which are often many miles long, rock shelters are almost always modest in size and extent.

Formation

Rock shelters form because a

rock Rock most often refers to: * Rock (geology), a naturally occurring solid aggregate of minerals or mineraloids * Rock music, a genre of popular music Rock or Rocks may also refer to: Places United Kingdom * Rock, Caerphilly, a location in Wales ...

stratum such as sandstone that is resistant to

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 dis ...

and

weathering Weathering is the deterioration of rocks, soils and minerals as well as wood and artificial materials through contact with water, atmospheric gases, and biological organisms. Weathering occurs ''in situ'' (on site, with little or no movement) ...

has formed a cliff or bluff, but a softer stratum, more subject to erosion and weathering, lies just below the resistant stratum, and thus undercuts the cliff. In arid areas,

wind Wind is the natural movement of air or other gases relative to a planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heating of land surfaces and lasting a few ho ...

erosion (

Aeolian erosion Aeolian processes, also spelled eolian, pertain to wind activity in the study of geology and weather and specifically to the wind's ability to shape the surface of the Earth (or other planets). Winds may erode, transport, and deposit materials ...

) can be an important factor in rockhouse formation. In most humid areas, the most important factor in rockhouse formation is frost spalling, where the softer, more porous rock underneath is pushed off, tiny pieces at a time, by frost expansion from water frozen in the pores. Erosion from moving water is seldom a significant factor. Many rock shelters are found under

waterfalls A waterfall is a point in a river or stream where water flows over a vertical drop or a series of steep drops. Waterfalls also occur where meltwater drops over the edge of a tabular iceberg or ice shelf. Waterfalls can be formed in several w ...

. File:Rock shelter formation by frost weathering.svg, By

frost weathering Frost weathering is a collective term for several mechanical weathering processes induced by stresses created by the freezing of water into ice. The term serves as an umbrella term for a variety of processes such as frost shattering, frost wedg ...

File:Rock shelter formation by karst gallery cutting.svg, By cutting a karst gallery File:Rock shelter formation by river erosion.svg, By

river 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 dist ...

Human habitat

Excavation at Paleolithic site of Bawa Yawan, Zagros, Iran 2017

Rock shelters are often important archaeologically. Because rock shelters form natural shelters from the weather, prehistoric humans often used them as living-places, and left behind debris, tools, and other artifacts. In mountainous areas the shelters can also be important for

mountaineers Mountaineering or alpinism, is a set of outdoor activities that involves ascending tall mountains. Mountaineering-related activities include traditional outdoor climbing, skiing, and traversing via ferratas. Indoor climbing, sport climbin ...

Transhumant Transhumance is a type of pastoralism or nomadism, a seasonal movement of livestock between fixed summer and winter pastures. In montane regions (''vertical transhumance''), it implies movement between higher pastures in summer and lower val ...

nomads, people who move with their livestock - often from lower permanent winter residences in the valleys to higher summer pastures - frequently build semi-permanent camps, often of rocks. In western

Connecticut Connecticut () is the southernmost state in the New England region of the Northeastern United States. It is bordered by Rhode Island to the east, Massachusetts to the north, New York to the west, and Long Island Sound to the south. Its capita ...

and eastern New York, many rock shelters are known by the colloquialism "leatherman caves", as they were inhabited by the Leatherman over three decades in the late 19th century.

Unique vegetation

The Cumberland stitchwort (''Minuartia cumberlandensis'') is an endangered species of plant which is found only in rock shelters in Kentucky and Tennessee.Center for Plant Conservation

References

External links

* {{Authority control

Formation

Human habitat

Unique vegetation

See also

References

Further reading

External links