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Most LS is generated on highlands by erosional processes related to mass-wasting, sheet flow, rills and gullies. The deposited colluvium has a low travel distance and accumulates in midslope drapes near the site of erosion, in aprons or sediment wedges at the base of the slope or in fans at the mouth of gullies, debris flows and tributaries. [1]
BRM in a rock shelter on the Upper Cumberland Plateau.. A bedrock mortar (BRM) is an anthropogenic circular depression in a rock outcrop or naturally occurring slab, used by people in the past for grinding of grain, acorns or other food products. [1]
In the broad sense [2] [4] of the term, volcaniclastics includes pyroclastic rocks such as the Bandelier Tuff; [5] cinder cones and other tephra deposits; the basal and capping breccia that characterize ʻaʻā lava flows; and lahars and debris flows of volcanic origin. [6] Volcaniclastics make up more of the volume of many volcanoes than do ...
Detailed map of Mount Rainier's summit and northeast slope showing upper perimeter of Osceola collapse amphitheater (hachured line) The Osceola Mudflow, also known as the Osceola Lahar, was a debris flow and lahar in the U.S. state of Washington that descended from the summit and northeast slope of Mount Rainier, a volcano in the Cascade Range during a period of eruptions about 5,600 years ago.
Debris flows with volumes ranging up to about 100,000 cubic meters occur frequently in mountainous regions worldwide. The largest prehistoric flows have had volumes exceeding 1 billion cubic meters (i.e., 1 cubic kilometer). As a result of their high sediment concentrations and mobility, debris flows can be very destructive.
A mudflow, also known as mudslide or mud flow, is a form of mass wasting involving fast-moving flow of debris and dirt that has become liquified by the addition of water. [1] Such flows can move at speeds ranging from 3 meters/minute to 5 meters/second. [ 2 ]
Blanks are the starting point of a lithic reduction process, and during prehistoric times were often transported or traded for later refinement at another location. Blanks might be stones or cobbles, just as natural processes have left them, or might be quarried pieces, or flakes that are debitage from making another piece. Whatever their ...
It is commonly found within the margins of rhyolitic lava flows known as obsidian flows. These flows have a high content of silica, giving them a high viscosity. The high viscosity inhibits diffusion of atoms through the lava, which inhibits the first step in the formation of mineral crystals. Together with rapid cooling, this results in a ...