At last, a theory about why Denver is a mile above sea level

Geologists may finally be able to explain why Denver, the Mile High City, is a mile high: water. A new theory suggests that chemical reactions, triggered by water far below the Earth’s surface, could have made part of the North American plate less dense many millions of years ago, when the continents we know today were still forming. Because plates float on the Earth’s mantle, parts of the Western United States might have risen, like an empty boat next to one with a heavy cargo, pushing the vast High Plains far above sea level, according to the theory formulated by geologists Craig Jones and Kevin Mahan at the University of Colorado-Boulder.

Science