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 Ear ...

and

geomorphology Geomorphology (from Ancient Greek: , ', "earth"; , ', "form"; and , ', "study") is the scientific study of the origin and evolution of topographic and bathymetric features created by physical, chemical or biological processes operating at or n ...

a paleosurface is a surface made 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 distin ...

of considerable antiquity. Paleosurfaces might be flat or uneven in some cases having considerable relief. Flat and large paleosurfaces —that is

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 ...

s— have higher potential to be preserved than small and irregular surfaces and are thus the most studied kind of paleosurfaces. Irregular paleosurfaces, albeit usually smaller than flat ones, occur across the globe, one example being the

Sudetes The Sudetes ( ; pl, Sudety; german: Sudeten; cs, Krkonošsko-jesenická subprovincie), commonly known as the Sudeten Mountains, is a geomorphological subprovince in Central Europe, shared by Germany, Poland and the Czech Republic. They consis ...

etchsurfaces. In the case 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 ...

s it is argued that they become paleosurfaces once they are detached from the

base level In geology and geomorphology a base level is the lower limit for an erosion process. The modern term was introduced by John Wesley Powell in 1875. The term was subsequently appropriated by William Morris Davis who used it in his cycle of erosion ...

they grade to. Paleosurfaces form an important part of the

geologic record The geologic record in stratigraphy, paleontology and other natural sciences refers to the entirety of the layers of rock strata. That is, deposits laid down by volcanism or by deposition of sediment derived from weathering detritus (clays, sand ...

in that they represent geological and geomorphological events. Traditionally geologist and geomorphologist view paleosurfaces differently. Geologists look into the

endogenic Endogenous substances and processes are those that originate from within a living system such as an organism, tissue, or cell. In contrast, exogenous substances and processes are those that originate from outside of an organism. For example, e ...

or constructive processes occurring to create that surface, such as crustal uplift and

igneous Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or ...

activity. The stratigraphic record is valued by geologists allowing for a broader range of surface types to be considered. However, when paleosurfaces are viewed by geomorphologists the

exogenic In a variety of contexts, exogeny or exogeneity () is the fact of an action or object originating externally. It contrasts with endogeneity or endogeny, the fact of being influenced within a system. Economics In an economic model, an exogeno ...

or deconstructive processes are considered. This is because geomorphologists are primarily concerned with erosional 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), ...

processes. Geomorphologist Richard Huggett lists paleosurfaces as one of various categorizations of paleoplains.

References

Erosion landforms Geomorphology Unconformities {{geology-stub

See also

References