EH2: WED, Sand and Soil

Consider the diagram of a flowing river. A rain storm causes a large amount of water to flow through the river in a very short time.

What size sediments would you expect to find at location Z?

• Large sediments

• Medium sediments

• Small sediments

The Colorado River started eroding the Grand Canyon 6 million years ago. Of the layers shown at location X, which two layers did the Colorado River erode away first?

• Kaibab Formation and Toroweap Formation

• Redwall Limestone and Supai Group

• Bright Angel Shale and Tapeats Sandstone

• All layers are eroded at the same time by the Colorado River

If rocks from a mountain top (MT) are weathered and washed downhill into a river, at which location would you expect to find the smallest sediments?

• Location A

• Location B

• Location C

• Location D

Which geological processes occurred in these two cases?

• X: physical weathering

  Y: chemical weathering

• X: wind erosion

  Y: compaction

• X: differential erosion

  Y: wind weathering

• X: chemical weathering

  Y: ice damage

When rocks are broken apart by abrasion (hitting together) from wind and/or water, or frost, or root wedging, the process is called

• chemical weathering

• erosion

• physical weathering

• deposition

Many people think that weathering and erosion are the same process. After studying this unit, you now know that

• weathering only happens in winter.

• erosion wears down rocks into smaller pieces and weathering moves them away.

• erosion always takes millions of years to change a landform.

• weathering wears down rocks into smaller pieces and erosion moves them away.

Which explanation best describes how a boulder can turn into silt as it moves down a river?

• Water washes over it until it is silt-sized.

• It hits other rocks or objects and breaks apart.

• It moves until it reaches a basin & becomes silt.

• It deposits into silt in the basin.

What is humus, and how does it form?

• Forms when broken bits of rock wash into the soil.

• Organic matter in soil that forms when rocks break down.

• Rock material that forms when plants & animals poop.

• Organic matter formed when plants and animals decay or poop.

Rain washing soil away from a hillside is an example of

• Abrasion

• Erosion

• Deposition

• Weathering

The process of sediment being dropped off in a new place is called

• Abrasion

• Erosion

• Deposition

• Weathering