Science concepts ch. 11

Describe features formed by wave deposition.

A spit is a feature formed from wave deposition. Deposits from longshore drift can cause this - a ridge of sand that extends away from the shore. Waves may also deposit sediments to form sandbars and barrier islands. A barrier island is a long, narrow island.

Identify ways to protect shorelines from wave erosion.

Breakwaters are parallel to the shore and storm waves strike them first. They are man-made. A groin is a wall of rock perpendicular to the shore that also serves the same purpose.

Identify causes and effects of landslides and mudslides.

Landslide:mass movement of large amounts of rock and soil. Causes: gravity causes mass movement. Effect: may be tsumani. Mudslide: Sudden flow of mud down a slope cause: lots of rain, gravity. effect: engulfs whatever is in its path.

Identify features caused by groundwater erosion and deposition.

Caves can form from groundwater erosion. Groundwater drips from the ceiling to the floor of a cave. This water is rich in dissolved minerals. They build up on the ceiling to create formations called stalactites. They drip to the floor of a cave and harden to form stalagmites. Sinkholes can also form if the ceiling of the cave collapses.

Explain how flowing water causes erosion and deposition.

Flowing water will break down sediment from rock (weathering), move them to another location (erosion), and then deposit them where the stream turns or ends (deposition). Erosion happens faster with faster streams. As water slows, larger particles are deposited. As the water slows even more, smaller particles are deposited.

Identify landforms deposited by glaciers.

Glacial till - a mixture of particles and rocks when the water melts Moraine - thick layer of sediment deposited by retreating glacier Drumlin - a long, low hill of sediment deposited by glacier. Esker - winding ridge of sand deposited by a stream of meltwater. Kettle Lake - a lake formed from a chunk of ice melting from the glacier

Describe how continental and valley glaciers form.

Glaciers form when more snow falls than melts each year. Over years, the snow compact and turns into ice. When it covers most of the continent, we call these continental glaciers. If it is long and narrow and forms in mountains and flows downhill, these are valley glaciers.

Identify ways to prevent wind erosion.

Good soil with plants will help prevent wind erosion. Planting trees, shrubs, etc. will help. Also, building fences can help as well.

Explain how glaciers cause erosion.

Like flowing water, flowing ice erodes the land and deposits materials elsewhere. The two main ways that this happens is through plucking - picking up sediment by the glacier as it moves - and abrasion, scraping underlying rock as it moves.

Explain how wind causes erosion.

Like flowing water, wind picks up and transports particles. Wind carries particles that are tiny such as clay and silt by suspension. They are high above the ground and are carried for a long time. Larger particles, such as sand move by saltation. The wind blows in short hops. Larger particles than that move by traction, they roll over the surface. During the transport of particles, abrasion occurs. This is sandblasting - scouring and polishing rocks and other surfaces.

Describe how runoff, streams, and rivers change Earth's surface.

Runoff occurs when there is too much water in a short period of time and the ground can't absorb it all. It will flow downhill due to gravity. Sediments can be carried this way. Streams and rivers will carve a v-shaped channel. They flow quickly and cause a lot of erosion. However, they have little deposition. Mountain streams may cause waterfalls if the softer rock is eroded faster than the harder rock causing the stream bed to drop. Rivers flowing over gentle slopes erode the sides of their channel more than the bottom. These large curves are called meanders. If the meander breaks off from the rest of the stream it can form an oxbow lake. As meanders erode from side to side, they form a floodplain. Alluvial fans form when large deposits come to a stop rapidly. Deltas form when a river empties into a large body of still water. Levees can also form from the sediment being deposited on the streams' water's edge.

Describe sediments deposited by wind.

Sand dunes are formed by plenty of sand and wind. This happens mostly in deserts. Clay and silt can be deposited (loess) and form vertical cliffs.

Explain how slump and creep occur.

Slump - sudden movement of large block of rock and soil down a slope. It may be cause by a layer of slippery, wet clay underneath the rock and soil on a hillside. Creep - very slow movement of rock and soil down a hillside. It can happen where the land freezes and thaws quickly.

Explain how waves cause erosion of shorelines.

Waves are energy traveling through matter. This can be water, for example. The size of the wave depends on the speed of the wind, the length of the wind blows, and the distance of the wind blows. Cliff form when waves erode a rocky shoreline. Sea arches form when waves erode both sides of a cliff. Sea stacks form when waves erode the top of a sea arch. Also, longshore drift is the process in which sediment is moved downshore through waves moving the particles back and forth from the sea to shore.