Index map
The mid-section of the continent is beginning to be pulled apart by extensional forces. Volcanism accompanies this activity. The upper Rio Grande River flows southward through New Mexico within a long fault-bounded basin, the Rio Grande Rift, where lava from a source deep in the mantle periodically spreads across the surface. In the near geologic future, several million years or so, a youthful ocean basin may occupy this area. |
