A stone stripe, also called a lava stringer, is an elongated concentration of mostly talus-like

basalt Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...

rock found along a

hill A hill is a landform that extends above the surrounding terrain. It often has a distinct summit, and is usually applied to peaks which are above elevation compared to the relative landmass, though not as prominent as Mountain, mountains. Hills ...

side or the base of a

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. ...

. Many stone stripes occur without cliffs. A stone stripe is identified by its lack of

vegetative cover Vegetation is an assemblage of plants and the ground cover they provide. It is a general term, without specific reference to particular taxa, life forms, structure, spatial extent, or any other specific botanical or geographic characterist ...

. They typically occur in north

central Oregon Central Oregon is a geographic region in the U.S. state of Oregon and is traditionally considered to be made up of Deschutes, Jefferson, and Crook counties. Other definitions include larger areas, often encompassing areas to the north towards t ...

and develop at 900 to 1,100 meter elevations. Lengths can range from only a few meters to over 150 meters, and widths measure from .3 to 3 meters. Depths of the stone stripes range from 20 to 65 centimeters.

Formation

Stone stripes are thought to have been originally created by

periglacial Periglaciation (adjective: "periglacial", referring to places at the edges of glacial areas) describes geomorphic processes that result from seasonal thawing and freezing, very often in areas of permafrost. The meltwater may refreeze in ice wedg ...

conditions of the

Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS), as well as the current and most recent of the twelve periods of the ...

period during an

Ice age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages, and g ...

. It is likely their formation originates from multiple processes including

frost action 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 we ...

, surface erosion,

eluviation In geology, eluvium or eluvial deposits are geological deposits and soils that are derived by ''in situ'' weathering or weathering plus gravitational movement or accumulation. The process of removal of materials from geological or soil horizons ...

, and

mass wasting Mass wasting, also known as mass movement, is a general term for the movement of rock (geology), rock or soil down slopes under the force of gravity. It differs from other processes of erosion in that the debris transported by mass wasting is no ...

. However, it is likely that intense freeze and thaw cycles account for the natural sorting of the rock debris within a stone stripe, and also accounts for the shallow depth of the stripes, since frost penetration is thought to not penetrate deeper than 1 meter in the region. Stone stripes are also found surrounding soil mounds of central Oregon which also owe their formation to freeze and thaw cycles. They are called stone rings and form on more level terrain. As the terrain increases in slope, stone rings transition into stone stripes.

Gallery

File:Lava Stringer 4.jpg, Stone stripes on Catlow Rim with

juniper Junipers are coniferous trees and shrubs in the genus ''Juniperus'' ( ) of the cypress family Cupressaceae. Depending on the taxonomy, between 50 and 67 species of junipers are widely distributed throughout the Northern Hemisphere as far south ...

trees. File:Lava Stringer 1.jpg, Stone stripes on Catlow Rim. File:Lava Stringer 9.jpg, Stone stripes on Catlow Rim.

External links

Mystery of the Desert Mounds

References

Slope landforms Regolith Landscape ecology Basalt {{topography-stub

Formation

Gallery

See also

External links

References