Chapter 10.4

delta

A delta, for example, is an area of built-up sediment deposited where a river empties into an ocean or a lake. When fast-moving river water enters a body of water, it slows down and begins to drop the sediments it has carried downstream. The pattern created by these deposited sediments is usually triangular (or fan-shaped). Because deltas make good locations for growing food and launching ships, many of the world's largest cities began as settlements on or near deltas.

Fiord

A narrow inlet of ocean between steep cliffs carved by glaciers

erosion

After rock becomes weakened and broken down into fragments, those pieces can be transported (that is, carried away) from their original location. This process is called erosion.

striations

As described earlier in this section, glaciers have shaped much of our province's landscape. The place where you live looked a lot different 10 000 years ago when the entire province was buried by ice sheets. In some parts of British Columbia, the ice was almost 2000 m deep. As the ice sheets were pulled slowly downhill by gravity, they scraped and carved the land they were passing over. Scratch marks, or striations

Cirque

Bowl-shaped valley at the head of a glacier

biological weathering

If physical or chemical weathering has been caused by a plant or animal, the process is sometimes referred to as biological weathering

karst

If the dissolved rock material lies close to the surface, or if the cave formed by the dissolving rock collapses, sinkholes can result and become visible on the surface. An area with many sinkholes is called karst

sinkholes

If the dissolved rock material lies close to the surface, or if the cave formed by the dissolving rock collapses, sinkholes can result and become visible on the surface. An area with many sinkholes is called karst

Erratic

Large boulder deposited on the ground by a glacier

Outwash

Material deposited by water from melting glaciers

Arête

Narrow ridge (high ground) between two cirques

Horn

Pyramid-shaped peak located between three cirques

Moraine

Ridge of rocky material deposited by a glacier. Moraines can be found at the sides and farthest advance of a glacier.

Hanging valley

U-shaped valley cut off by a bigger valley created by a larger glacier

landslide

When rain soaks the slopes of a steep hill or mountain, the soil and other rock material can become so heavy that they are unable to resist the force of gravity acting on them. The result can be that a large part of the hillside or mountainside will fall away and slide downward, sometimes with catastrophic results. Such a sudden, rapid movement of rock material down the slope of a hill or mountain is called a landslide. An avalanche is a landslide of ice and snow. Landslides can cause tremendous damage and even result in loss of human life.

Esker

Winding ridge of material deposited by a stream running under a glacier

chemical weathering

a chemical reaction causes rocks to break down, or decompose.

caves

ittle by little, the small gaps "eaten" into the rock become bigger gaps and, over thousands of years, these grow to be large holes and sometimes very large underground caves

deposition

reaking down and removing rock are major ways of changing the look of the landscape, but Earth's surface is also changed by being built up. One way that happens is through a process called deposition.

physical weathering

rocks are broken down by physical means, such as being scratched to bits by harder rocks, but they do not change their composition.

Weathering

the process of breaking down rock into smaller fragments. There are two main types of weathering: physical weathering and chemical weathering