re: #259 celticdragon

Rapid near horizontal subduction of the Fallaron Plate beneath the western margin of the North American Plate effectively chilled the lithosphere and greatly reduced the geothermal gradient between 75 Ma and 45 Ma (Late Cretaceous into the Tertiary). This effectively strengthened the crust while transmitting stress deep into the craton of North America, which resulted in the uplift of the Rocky Mountains. The Fallaron Plate eventually fell away towards the earth’s core, and increased magmatism throughout present day Nevada and eastern California resulted in the lithosphere being tremendously reheated and weakened. The weakened crust underwent gravitational collapse (a bit like a block of cheese left out in the sun) and resulted in the basin and range province where crustal extension is shown by huge, normal dip slip fault block mountain ranges.

As I was driving across the Rockies last Sunday, I was wondering about the process that created them. That’s just a little freaky that you answered it on the first day I spent any significant time here since then.