Deseret News | Reader comments: Heat may explain why West is grand

Reader comments
Heat may explain why West is grand

Heat? | 8:03 a.m. June 22, 2009

I'm sure geologists are slapping their foreheads and exclaiming; "heat, of course! why didnt I see it? On the other hand, Im just slapping my forehead and saying, huh? I dont get it. How does heat make the massive rock rise 6,000 feet? Is it like a hot air balloon? Im sure theres a comprehensible answer, but this article didnt do it for me. Can anyone elucidate? As an amateur, geological enthusiast Id really like to know.

Dear Heat? | 10:04 a.m. June 22, 2009

This is a newspaper article intended to summarize rather than provide the details. You can read the original scientific report in Nature which is available on line (you probably have to pay to view). If you still have questions you might try contacting professor Pederson at Utah State. Maybe he'll email you the Nature article for free. All of this requires effort but if you really want to know the answers to your questions I am sure it will be worth it.

NorthboundZax | 10:34 a.m. June 22, 2009

Heat - your analogy to a hot air balloon is actually on the right track. Mantle rocks expand about 3 parts in 10,000 per degree C. In the authors' model, they inject hot asthenosphere (hot, lower viscosity mantle) beneath the lithosphere (cool, mostly rigid mantle) which tends to buoy up the entire structure like a hot-air balloon.

The news article doesn't mention it, but important to the buoyancy is that the Colorado Plateau is an area that is low in iron. As iron is dense and often abundant, the lack of iron is like dropping some of the ballast from the hot-air balloon so the heat expansion effect can make more of a difference.

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