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

basalt Basalt (; ) is an 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 surface of a rocky planet or moon. More than 90 ...

rock found along a

hill A hill is a landform that extends above the surrounding terrain. It often has a distinct summit. Terminology The distinction between a hill and a mountain is unclear and largely subjective, but a hill is universally considered to be not a ...

side or the base of a

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 ...

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

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 20-65 centimeters.

Formation

Stone stripes are thought to have been originally created by

periglacial Periglaciation (adjective: "periglacial", also referring to places at the edges of glacial areas) describes geomorphic processes that result from seasonal thawing of snow in areas of permafrost, the runoff from which refreezes in ice wedges and o ...

conditions of the Quaternary 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 gre ...

. It is likely their formation originates from multiple processes including frost action, surface erosion,

eluviation In geology, eluvium or eluvial deposits are those 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 horiz ...

, and

mass wasting Mass wasting, also known as mass movement, is a general term for the movement of 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 not entrained in ...

. 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 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