Ridge

A ridge is a long, narrow, elevated landform. It has steep sides, and the top is called the crest or ridgecrest. If the crest is very narrow, it is called a ridgeline.

The southern ridge of the Mt Sylvia Range, a ridge composed of several peaks, viewed from the Lishan area of Taiwan

Ridges can be small or very tall. They can form in many ways, such as from depositional processes, erosional forces, or tectonic movements. Ridges can be made of solid bedrock, loose sediment, lava, or even ice.

Ridges can stand alone or be part of bigger landscapes. Learning about ridges helps scientists understand how Earth’s surface changes.

Classification

Ridges can be grouped in many ways, such as how they were formed, how they look, or what they are made of.

One way to classify ridges looks at the natural process that shaped the land. This method splits landforms into two big groups: Geomorphic Environments and Other Groupings, with 16 smaller groups. Ridges can appear in many of these groups, such as those formed by wind, water, glaciers, volcanoes, or tectonic forces.

Aeolian ridge

An aeolian dune ridge is a ridge made of sand piled up by the wind. Sand dunes can be small hills or long ridges, and can be a few centimeters to over 150 meters tall. Very large dunes, called megadunes or draas, can have smaller dunes on top of them.

Coastal ridges

A beach ridge is a low, continuous ridge made of sand and other materials from the beach, formed by waves and currents. These ridges are found along shorelines, often in lines running parallel to the coast.

A strike ridge within the Appalachian Mountains

Erosional ridges

In areas where plateaus have been worn down by rivers, the valleys leave behind ridges in between. These ridges are very common and usually occur where the rock is slightly harder to erode. They often change direction and can have rounded bumps on top.

Glacial ridges

Glacial movements can leave behind ridges called moraines and eskers. An arête is a thin ridge of rock shaped by glacial erosion.

Tectonic and Structural ridges

In areas where tectonic plates spread apart, volcanic activity creates new land and forms ridges, like at the Mid-Atlantic Ridge. Large asteroid impacts can also create circular ridges around the craters they form.

Volcanic and hydrothermal ridges

In volcanic areas, ridges can form from lava flows pushing up under a hardened surface. Large volcanoes often have craters or calderas with ridges around their edges. When volcanoes erupt under glaciers, they can create ridges made of volcanic ash.