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 caves (

karst Karst is a topography formed from the dissolution of soluble rocks such as limestone, Dolomite (rock), dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves. It has also been documented for more weathe ...

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

Formation

Rock shelters form because a rock 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 d ...

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 ...

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 mate ...

) 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. File:Rock shelter formation by frost weathering.svg, By frost weathering File:Rock shelter formation by karst gallery cutting.svg, By cutting a

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

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 climbing, ...

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 (state), New York to the west, and Long Island Sound to the ...

and eastern New York, many rock shelters are known by the

colloquialism Colloquialism (), also called colloquial language, everyday language or general parlance, is the linguistic style used for casual (informal) communication. It is the most common functional style of speech, the idiom normally employed in conversa ...

"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