black lava flow to drop down next to older rocks including the red lake sediments. There really are cases where lava hardens in cracks, or where lava flows fill valleys, but a careful examination of the rocks here shows that the lake sediments have not been heated by really nearby lava, so these lake sediments and the lava must have been placed together after the lava cooled. Push-together faulting, and landslides, do occur, but not here. , Points Earned: , 1/1 Your Response: , C 2. , In Death Valley: , A. , The main motion has been separation of the mountains east and west of the valley, shifting away from the center of the valley. B. , The rocks under the valley floor have been moving down relative to similar rocks in nearby mountains, and at the same time the mountains east and west of the valley have been moving apart, away from the center of the valley. C. , The rocks under the valley floor have been moving down relative to similar rocks in nearby mountains, while the mountains east and west of the valley have been moving toward the center of the valley. D. , The main motion has been the shifting of mountains east and west of the valley toward the center of the valley. E. , The main motion has been the downward shift of rocks under the valley floor relative to similar rocks in nearby mountains.
The pull-apart action that is spreading Death Valley and surroundings also involves uplift of mountains or downdrop of valleys, and Death Valley has dropped as its flanking mountains have moved apart. , Points Earned: , 1/1 Your Response: , B 3. , The floor of Death Valley is about two miles lower than the mountain peaks around it. How did this happen? , A. , The elevation difference between the peaks and valley was once much larger than two miles, but the valley floor has been rising as it is inflated by lava from below. B. , The valley was once filled with a giant lake of Pepsi, and early miners collected the Pepsi and hoarded it so they could sell it to Penn State after the university signed an exclusive licensing agreement. C. , The valley floor has dropped by more than two miles relative to the mountains, but erosion has removed the mountain tops and the sediment produced has partially filled the valley, leaving an elevation difference of two miles. D. , The valley was carved two miles deep by a prehistoric river, much in the same way that the Colorado River carved the Grand Canyon. E. , The valley floor has dropped by two miles relative to the mountains. Watch a stream flowing into Death Valley (or any other valley) during a thunderstorm, and you will see that the water is full of rocks, mud, etc. The mountains are being eroded, and the loose pieces are carried down and dumped into the valley. Yet the mountain peaks are still two miles above the floor of Death Valley; the erosion and deposition are fighting against faulting that has dropped the valley by more than two miles relative to the mountains. No river carved the valley; the rivers are filling it up. And strange as it may seem, the valley is older than Pepsi, and certainly
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