Define and describe the formation of an alluvial fan. How does it differ from a delta?
What will be an ideal response?
When a stream flows out of a narrow bedrock channel in a mountain range, it forms a fan-shaped mass of alluvium called an alluvial fan because the water enters a broad valley where there are no hard-rock valley walls to confine the flow. Alluvial fans form when the discharge of the stream does not change, but the flow is deeper in the upstream channel than it is where the water spreads out downstream as a shallow sheet. The shallower flow exerts less shear stress, and this means the stream power drops, so sediment abruptly deposits to form the fan. A delta is the landform produced by deposition of sediment where a stream enters a lake, reservoir, or sea. Deltas form when there is a drop in stream velocity as it reaches the standing body of water and this causes a drop in stream power which leads to deposition.
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Paleozoic and Mesozoic marine invertebrate faunas differ primarily because ____
a. mammals had not yet evolved in the Paleozoic b. birds had not yet evolved in the Paleozoic c. most Paleozoic faunas were nektonic d. Mesozoic fauna with hard and soft parts burrowed in the sediment e. more Mesozoic fauna were nektonic
The fall of the Library of Alexandria can be attributed to growing tensions between Hypatia and early
Christian Romans. Indicate whether the statement is true or false.
Which desert is the driest place on Earth?
a. The Sahara Desert b. The Gobi Desert c. The Atacama Desert d. The Kalahari Desert
Briefly describe the various surface water resources. Which resources are available in your area? What are the large water projects in your area, such as water transfer pr or dams?
What will be an ideal response?