Terrain Features

by Manasa Muppirala

Caldera

Calderas are massive crater-like depressions, and can extend for several miles. When a volcano erupts, if enough magma is ejected from the magma chamber at the bottom of the volcano, then the chamber empties. This empty chamber is unable to support the structure of the volcano, which is all lying right on top of it, and so the volcano basically collapses in on itself. Think of it like pulling a card from the very bottom of a card tower. The volcano sinks to the ground, and causes this enormous explosion that obliterates anything in the surrounding area and leaves this enormous crater.

Delta

All rivers carry sediment, they pick it up from the land they flow past along the way. When a river reaches the ocean, it slows down and loses the power to carry all this sediment. So, it deposits all of it at the mouth (where the river meets the sea). These sediments build up into layers and form a delta.

Escarpment

An escarpment is a break in slope that separates one level of terrain from another, so it's basically like a margin between the two different elevations. They usually have very steep-sided slopes and the two landforms they separate are leveled out. Escarpments can be formed by faulting and erosion, or even a combination of the two.

Fjord

A fjord is formed when a glacier cuts a gorge below sea level and then backs off. After the glacier joins the ocean, seawater flows into the valley it has carved and it becomes a narrow inlet with very steep sides.

Inselberg

Inselberg literally means "island mountain" in German, and that is exactly what it looks like. An inselberg is like a little knob of rock that rises from a gently sloping or virtually level area of surrounding land. Volcanic or other processed may cause a body of rock resistant to erosion to be embedded within another layer of rock that's less resistant. So, when this less resistant rock has eroded away, the more resistant rock inside is left behind as an isolated mountain.

U Shaped Valley

This type of valley has broad walls and steep floors, and is formed by glacial erosion. As a glacier passes through a V shaped valley, which is carved by a river, it widens and deepens this original valley into a U shape after the ice has eroded the sides and bottom.

Wind Gap

A wind gap, or water gap, is a valley through which a waterway once flowed but is now dry as a result of stream capture. Stream capture is a process by which a river's course is diverted from its own riverbed into another be. This can be for any number of reasons, such as plate tectonics, severe erosion, or natural damming.