COLORADO PLATEAU L25 



nomenon in the mantle must be sought to explain the uplift. Expansion turn to the partial melting hypothesis as the principal cause of widespread 



of the underlying column of the mantle, either due to phase changes or uplift. The subject is elaborated on in the final pages of Chapter 36. The 



partial melting, or to both, seems an immediate recourse. Since magmatic asymmetrical uplifts may be great blisters incident to an early stage of 



activity is widespread in and around the Plateau, the writer is prone to megasill intrusion in the crystalline basement 



