The Process and Definition of Geomorphology

An explorer beholds the massive ice formations of a dramatic glacier
Tyler Stablefield/Getty Images 

Geomorphology is the science of landforms, with an emphasis on their origin, evolution, form, and distribution across the physical landscape. Understanding geomorphology is therefore essential to understanding one of the most popular divisions of geography. Studying geomorphological processes provides significant insight into the formation of the various structures and features in landscapes worldwide, which can then be used as a background for studying many other aspects of physical geography.

History of Geomorphology

Although the study of geomorphology has been around since ancient times, the first official geomorphologic model was proposed between 1884 and 1899 by the American geographer William Morris Davis. His geomorphic cycle model was inspired by theories of uniformitarianism and attempted to theorize the development of various landform features.

Davis's theories were important in launching the field of geomorphology and were innovative at the time, as a new way to explain physical landform features. Today, however, his model is not usually used, because the processes he described are not so systematic in the real world. It failed to take into account the processes observed in later geomorphic studies.

Since Davis's model, several alternative attempts have been made to explain landform processes. For example, Austrian geographer Walther Penck developed a model in the 1920s that looked at ratios of uplift and erosion. It did not take hold, though, because it could not explain all landform features.

Geomorphological Processes

Today, the study of geomorphology is broken down into the study of various geomorphological processes. Most of these processes are considered to be interconnected and are easily observed and measured with modern technology. The individual processes are considered to be either erosional, depositional, or both.

An erosional process involves the wearing down of the earth’s surface by wind, water, and/or ice. A depositional process is the laying down of material that has been eroded by wind, water, and/or ice. There are several geomorphological classifications within erosional and depositional.

Fluvial

Fluvial geomorphological processes are related to rivers and streams. The flowing water found here is important in shaping the landscape in two ways. First, the power of the water moving across a landscape cuts and erodes its channel. As it does this, the river shapes its landscape by growing, meandering across the landscape, and sometimes merging with others to form a network of braided rivers. The paths rivers take depend on the topology of the area and the underlying geology or rock structure where it moves.

As the river carves its landscape, it also carries the sediment it erodes as it flows. This gives it more power to erode, as there is more friction in the moving water, but it also deposits this material when it floods or flows out of mountains onto an open plain, as in the case of an alluvial fan.

Mass Movement

The mass movement process, also sometimes called mass wasting, occurs when soil and rock move down a slope under the force of gravity. The movement of the material is called creeping, sliding, flowing, toppling, and falling. Each of these depends on the speed and composition of the material moving. This process is both erosional and depositional.

Glacial

Glaciers are one of the most significant agents of landscape change because of their massive size converts to power as they move across an area. They are erosional forces because their ice carves the ground beneath them and on the sides, which forms a U-shaped valley, as with a valley glacier. Glaciers are also depositional because their movement pushes rocks and other debris into new areas. The sediment created when glaciers grind down rocks is called glacial rock flour. As glaciers melt, they drop debris, which creates features like eskers and moraines.

Weathering

Weathering is an erosional process that involves the mechanical wearing down of rock by a plant’s roots growing and pushing through it, ice expanding in its cracks, and abrasion from sediment pushed by wind and water, as well as the chemical break down of rock like limestone. Weathering can result in rock falls and unique eroded rock shapes like those in Arches National Park, Utah.