calderas are currently happening in the rio grande rift zone.
calderas are currently happening in the rio grande rift zone.
what is currently happening in the rio grande rift zone?
calderas
the rift is presently nearly tectonically quiescent, but significant deformation and faulting with offsets of many kilometers were responsible for its formation starting about 35 ma. the largest-scale manifestation of rifting involves a pure-shear rifting mechanism, in which both sides of the rift pull apart evenly and slowly, with the lower crust and upper mantle (the lithosphere) stretching like taffy. this extension is associated with very low seismic velocities in the upper mantle above approximately 400 km depth associated with relatively hot mantle and low degrees of partial melting. this intrusion of the asthenosphere into the lithosphere and continental crust is thought to be responsible for nearly all of the volcanism associated with the rio grande rift.
rio grande rift
rio grande rift









































the rio grande rift is a north-trending continental rift zone. it separates the colorado plateau in the west from the interior of the north american craton on the east. the rift extends from central colorado in the north to the state of chihuahua, mexico, in the south. the rift zone consists of four basins that have an average width of 50 kilometers. the rift can be observed on location at rio grande national forest, white sands national monument, santa fe national forest, and cibola national forest, among other locations.
rio grande rift