Activity
7: Cutting Canyons and Building Deltas
Analysis
Questions:
1.
Define delta
A delta is a
fan shaped river landform that develops when sediments are deposited. (Deposition)
2.
Define erosion
Erosion is
the removal of sediments from an area.
3.
Define deposition
Deposition is sediments that settle out of flowing water.
4.
Define weathering.
Weathering is
an earth process that breaks down rocks into smaller pieces.
5.
Why did a delta form?
The delta
formed because there was fast moving water that pushed the sand to the bottom
to make a delta where it was flat. The flat catch basin had still not moving
water.
6.
Why did the sand “fall out” of the river?
The sand “fell
out of the river” because the water stopped flowing downhill when the catch
basin was flat. The bottom of the river is where the delta formed.
7. Can rainfall change the
shape of the land?
Rainfall
changes the shape of land by force and weathering. Weathering is breaking apart
rocks/soil and erosion is moving those broken pieces. The heavy rains will flow
into a puddle or go down a hill and can change the land. If the land is flat,
rain can cause flooding.
8. How does water flowing
down river create a canyon?
Water flowing
down river creates a canyon by the
fast waters of the river cause the rocks to weather and break. Then the
rocks/sediments get carried by the moving water and keep flowing down the
river. The rocks on the side break and it forms the canyon with the river at
the bottom. More erosion causes the canyon to get deeper and bigger.
9. What happens to the rock
that once filled up the canyon?
The rock that once filled up the canyon
was weathered
(broken) and eroded (moved) down the river. The river flows downhill and moves quickly. The
force of the moving water picks up the rocks and moves them. All the weathered
sediments eventually end up in a big body of water, possibly forming a delta. This is what happens to rocks
that once filled the canyon.
10. How does the movement of sediments (EROSION)
help make a cliff?
The movement of sediments, or erosion,
makes cliffs.
At the ocean, there are large waves and stronger winds, especially during a
storm. Without a jetty or pier, the waves will slam into the land and
eventually erode away the sediments forming a beach below and a cliff on the
land. This is commonly found in Cape Cod and coastal beach places. This is how moving sediments forms cliffs.
