A ridge in geography refers to an elevated, long, and narrow landform that rises above the surrounding terrain. It typically consists of a chain of hills or mountains, forming a continuous crest over an extended distance.
Defining Characteristics
A ridge is visually distinct, presenting as a raised strip of ground often extending for considerable distances. Its defining feature includes two sloping sides, known as flanks, which descend from a relatively narrow top.
The uppermost part of a ridge is referred to as its crest or summit line, sometimes also called a ridgeline. This crest represents the continuous line of highest points along the ridge, from which the terrain drops down on both sides. When depicted on topographic maps, ridges typically appear as U-shaped or V-shaped contour lines, with the closed end of the “U” or “V” pointing toward higher ground. The height of a ridge can vary significantly, ranging from less than a meter to hundreds of meters above its surroundings. Ridges can be formed through various geological processes, including mountain-building events, erosion, or tectonic activity.
Variations and Common Examples
Ridges manifest in diverse forms across Earth’s surface, each shaped by specific geological processes. Mountain ridges, for instance, are prominent chains of mountains or hills that often feature a series of peaks along their continuous elevated crest. The Appalachian Mountains in the eastern United States provide a well-known example of a region characterized by extensive mountain ridges.
Underwater, oceanic ridges, also known as mid-ocean ridges, represent vast mountain ranges formed where Earth’s tectonic plates spread apart. The Mid-Atlantic Ridge, running down the center of the Atlantic Ocean, and the East Pacific Rise are two of the most thoroughly studied examples. The rate at which these plates spread influences the ridge’s appearance; slow-spreading ridges, like the Mid-Atlantic Ridge, often have a deep rift valley at their crest, while fast-spreading ridges, such as the East Pacific Rise, tend to have a smoother volcanic summit.
Another type is an escarpment, which is a steep slope or long cliff that forms a ridge-like feature. These are typically created by faulting or the differential erosion of rock layers, resulting in one side being gently sloped and the other a steep scarp. The Niagara Escarpment in North America and sections of the Blue Ridge Mountains exemplify these formations. Glacial activity also forms distinct ridges called moraines, which are accumulations of rock debris and sediment deposited by glaciers. These can appear as lateral moraines along the sides of a glacier, medial moraines where two glaciers merge, or terminal moraines marking the furthest extent of a glacier’s advance.