Espanola basin

The definition of its boundaries is not fully settled, but the basin is usually defined such that it includes the cities of Santa Fe, Los Alamos, and Espanola.

The basin is partially filled with sediments eroded from the higher ground to the east and west or brought in by the ancestral Rio Grande.

The accumulated sediments in the center of the basin are about 2 to 3 km thick, becoming thinner to the east and pinching out against the Precambrian rock of the Sangre de Cristo Mountains.

At greater depths near the basin center, there is are thick beds of older sedimentary rock that may be an old lake deposit of the Eocene Galisteo or El Rito Formations.

Volcanic activity in the Cerros del Rio periodically dammed the river and created a large lake in the Espanola basin.