Quiz 5 Flashcards
Discuss a common cause for springs that occur in the sides of valleys such as the Grand Canyon
Many of these springs exist because they are mad in rocks such as limestone which is easily dissolved. These fractures are then widened, and intersect with other fractures which causes the water to rush out of the rock, creating the spring.
How is a losing river related to the local water table?
Losing rivers are related to the local water table because the water table is lower than the surface of the river. This means that the water flows down into the ground, and away from the channel
Discuss the primary reason why there was a large increase in water withdrawal in central and eastern Iowa from the confined Cambrian-Ordovician aquifer in the 1960’s
The wide spread use of fertilizers in central and eastern Iowa during the 1960’s lead to the increase in water withdrawal from the Cambrian-Ordovician aquifer. This is because the fertilizers contaminated the shallow wells people had been using for their drinking water.
Describe the reasons for and the processes involved in land subsidence. then briefly discuss one case of land subsidence that were discussed in class.
The reasons for land subsidence is the over pumping of ground water. This happens because as the water table drops the sediment compacts because water is no longer filling the porous spaces. One example of water subsidence is in the San Joaquin Valley of California where they have actually marked on telephone poles where the elevation of the land surface was.
Why are water withdrawals for center pivot irrigation from the Ogallala Aquifer in the Nebraska Sand Hills how greater than anytime since 1945 even though in areas of Kansas and Texas water withdrawals from the Ogallala Aquifer are declining or have been discontinued
Water withdrawals for center pivot irrigation in the Nebraska Sand hills because the sandy nature of the soil allows the aquifer to be replenished faster than in Texas and Kansas.
Two reasons why the water table levels of the Ogallala Aquifer are no actual increasing outside of the sand hills in eastern/southeastern Nebraskaf
One reason is that the sand hills in Nebraska allow for the water to more easily flow through the Rock and enter into the aquifer. Another reason is that the eastern/southeastern parts of Nebraska get more rainfall that the parts in the western part of the aquifer
Briefly what is the difference between weathering of rock and erosion of rock
Weathering is the breakdown of rocks whereas erosion is transportation of that broken down rock
Describe how frost wedging physically weathers rock
When water gets into the fractures of rocks and freezes the water expands. When this happens it causes the rocks to fracture and break apart even more
Describe how thermal expansion physically weathers rock
When rocks are heated by wildfires and by the sun they expand irregularly which can cause some parts of the rock to fracture and break apart
How does a weak acid one that is responsible for chemical weathering of rocks naturally form in the atmosphere
Ask Dr. May
Discuss one of the tree chemical weathering processes discussed in class then briefly discuss a product of the process you have chosen
Hydrolysis is a chemical weathering process where when minerals are exposed to water that is slightly abiding the water will change the chemical composition of that rock. The byproduct of this is that the rock now becomes very similar to that of clay
Briefly discuss on process of erosion of weathered rock
Running water is an example of water where the running water will pick up and carry the sediment and loose materials and carry them for miles.
If you walk up to an exposure of sediment in a rod cut how could you quickly distinguish alluvium from glacial till simply by the appearance of the sediment
Ask Dr. May
Why does wind generally transport smaller particle sizes than glaciers and running water
Wind generally transports smaller partial sizes because air is less dense than that of water or glaciers.
How does desert pavement form
Desert pavement forms over thousands of years when the finer materials are blown or washed away. Then over time the larger castes left undisturbed will get a dark desert varnish on them.
