iv. Yellowstone National Park: Hot spots may occur on continental lithosphere as
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iv. Yellowstone National Park: Hot spots may occur on continental lithosphere as well as oceanic lithosphere. For example, Yellowstone National Park is a huge volcanic caldera (collapsed summit of a volcanic cone) which we believe had a culminating eruption some 600,000 years ago. This is only the latest in a series of major caldera-forming eruptions that have traveled across the pacific northwest during the last 16 million years. in fact, we can track the movement of this stili-active voicanic hot spot as it has shifted from Oregon through Idaho (creating its Snake River Plain Volcanic Province) into Wyoming. Click here to view this track (click on the link to "Detail of Calderas" on that website for an even closer view). In actuality, the hot spot is stationary. It is the North American plate which is moving across it. How fast is the plate moving? We can apply the same method as before in order to calculate this rate. Study the map on the following link (U.S.G.S. VOLCANO HAZARDS FACT SHEET: Yellowstone: Restless Volcanic Giant) to determine the distance from the current hot spot to the 12.5 million year old Bruneau-Jarbridge Caldera in southern Idaho. Question #14 From the Yellowstone Hot Spot calculation, how fast is the North American plate moving? Show your work. Give your answer in centimeters per year. Question #15 In what direction is the North American plate moving? Explain how the Yellowstone hot spot shows this? Where do we expect the hot spot to be in another 12.5 million years?Explanation / Answer
14. The source of hotspot is more or less stationary at depth within the Earth, North American plate moving southwest across it. The average rate of movement of the plate in this area for the last 16.5 million years ago has been about 4.6 cm per year. If we analyze it at shorter intervals, it is to be moved about 6.1 cm per year from 16.5 million year ago until about 8 million years ago, then slowed to 3.3 cm per year for the past 8 million years ago. So on a perspective, the plate is moving at a rate of about 3.6 cm per year.
15. The plate is presently at North eastern edge of Yellowstone plateau region and it is moving towards southwest ward at a speed of 2-3 cm per year.
The hot spot defines the direction as normal faults lines and mantle plumes bounding the snake river plain region.
The hotspot is expected to be at twin hills region in another 12.5 million years as it moves at a speed of about 3.3 cm per year.
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