Rio Grande Gorge
The Rio Grande River is one of the twenty-five longest rivers in the world and the course it winds is controlled by the surrounding geology.
Seventy five million years ago, a piece of oceanic crust called the Farallon plate was sinking beneath western North America, building mountains and creating volcanoes. But, by about 30 million years ago, the interaction between these plates had changed. Instead of the continent being squeezed to push up mountains, the continent was instead pulled apart, creating normal faults and basins.
