3.The picture above shows river gravels in the bottom of Death Valley. Based on the lesson materials for this unit, a likely explanation for this occurrence of river gravelsin the valley bottom is:A) The valley was dropped relative to the mountains by faulting, and rivers now are carrying gravels down from the mountains into the valley.B) The valley was made by folding, which ground up the rocks into little pieces to make the gravel.C) The valley was paved with gravels by a movie company for a really spectacular stunt in the Dukes of Hazzard movie, involving long-distance car chases and Daisy leaping the boys’ car across the entire park.D) The valley was raised by faulting, bringing up gravels from subterranean caves.E) The valley is deep because it was carved by a river, which later dried up when the desert formed, leaving the gravels behind.
Feedback:Faulting dropped the valley (or raised the mountains, or more likely both), and the melting snows of the mountains feed rivers that carry rocks down into the valley, slowly filling it up while lowering the mountains. There really are deep canyons that were carved by rivers, but as we sawin class and online, Death Valley is not one of them. Rivers don’t run on the tops of mountains to deposit gravels. And Daisy was more into shorts than into long jumps.Correct Answer(s):ATable for Individual Question FeedbackPoints Earned:1.0/1.04.Geophysical evidence indicates that convection is occurring in the Earth’s mantle. What is the most likely physical explanation for why convection can occur in the mantle?
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- Fall '08
- Earthquakes, Correct Answer, Volcano, Death Valley