geology Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Ea ...

and geomorphology, an erosion surface is a surface of

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 ...

regolith Regolith () is a blanket of unconsolidated, loose, heterogeneous superficial deposits covering solid rock. It includes dust, broken rocks, and other related materials and is present on Earth, the Moon, Mars, some asteroids, and other terrestr ...

that was formed by

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 not by construction (e.g.

lava Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or un ...

flows,

sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sa ...

deposition) nor fault displacement. Erosional surfaces within the stratigraphic record are known as

unconformities An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval ...

, but not all unconformities are buried erosion surfaces. Erosion surfaces vary in scale and can be formed on a mountain range or a rock. Particularly large and flat erosion surfaces receive the names of

peneplain 390px, Sketch of a hypothetical peneplain formation after an orogeny. In geomorphology and geology, a peneplain is a low-relief plain formed by protracted erosion. This is the definition in the broadest of terms, albeit with frequency the usage ...

, paleoplain,

planation surface In geology and geomorphology a planation surface is a large-scale surface that is almost flat with the possible exception of some residual hills. The processes that form planation surfaces are labelled collectively planation and are exogenic (chi ...

pediplain In geology and geomorphology a pediplain (from the Latin ''pes'', genitive case ''pedis'', meaning "foot") is an extensive plain formed by the coalescence of pediments. The processes through which pediplains forms is known as pediplanation. Th ...

. An example of erosion surface is road surface erosion which is caused by natural and anthropogenic factors. Erosion surface can be measured through direct, contact measurement methods and indirect, non-contact measurement methods.

Road surface erosion

Just like mountains and rocks, erosion can also occur on unsealed roads due to natural and anthropogenic factors. Road surface erosion could be caused by snowfall, rainfall and wind. The material and

hydraulic Hydraulics (from Greek: Υδραυλική) is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counte ...

of the road surface, road slope, traffic, construction, and maintenance could also potentially affect road surface erosion rate. During winter, snow cover slows down erosion rate by preventing direct contact between the raindrop and the road surface. For example, in the mountains of

Idaho Idaho ( ) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and Wyomi ...

, U.S., snowfall caused less than 10% while rainfall caused 90% of total annual

production on the road surface. In addition to natural factors, high traffic volume can also speed up the road erosion rates. The friction caused by moving vehicles could potentially lead to crushing and abrasion, thus break down the coarse particles on the road surface. Slope steepness is another important factor in surface erosion--steeper roads tend to have higher erosion rates. Rhizolith group revealed after wind erosion 3

Rhizolith group revealed after wind erosion 3

Measurement of erosion surface

There are two types of methods to measure the rate of surface change: direct, contact measurement methods and indirect, non-contact measurement methods. These measurement could be taken for different components of a rock or for different rock types. Rate of rock surface

recession In economics, a recession is a business cycle contraction when there is a general decline in economic activity. Recessions generally occur when there is a widespread drop in spending (an adverse demand shock). This may be triggered by various ...

can be measured by using reference points or reference planes and measure the distance among those points and plane over the years. Rock surface erosion rate can also be measured using Micro-Erosion Meter(MEM). This triangular instrument is placed on three studs that are permanently fixed into the rock surface to provide a measurement site. The extension of the probe is then used to measure erosion. Indirect, non-contact measurement methods include laser scanning and digital photogrammetry. While laser scanning requires many specialist and expensive equipment, repeat photography and digital photogrammetry can also be used to obtain data for researchers with a much smaller budget.

References

Erosion landforms Geomorphology {{geomorphology-stub