Earth and Planetary Sciences ETDs

Publication Date



In the Rio Puerco valley of Valencia and Sandoval Counties, New Mexico, immediately east of Mount Taylor and its associated lava flows are a series of ten prominent and exposed basaltic rocks. These bodies consist of alkali basalts exhibiting no systematic mineralogic or compositional trends throughout the area. The alkali basalts are composed of olivine, augite, plagioclase (labradorite), and opaques in a trachytic to felty groundmass. Each neck was emplaced by means of a convection cell mechanism that allowed the surrounding Cretaceous sediments to remain undisturbed by the intrusion. Contained in the alkali basalts are ubiquitous ultramafic inclusions of lherzolite and websterite, lherzolite being predominant. Little or no reaction zone is present between the inclusions and the basaltic host. These inclusions and the alkali basalts originated at depths probably in the range of 35-40 kilometers. Further, the inclusions were incorporated in the basalt from the mantle as it moved upward to its present position. They are not cumulates crystallized from the basalt but represent the residue of partial fusion of mantle material.

Degree Name

Earth and Planetary Sciences

Level of Degree


Department Name

Department of Earth and Planetary Sciences

First Committee Member (Chair)

Albert Masakiyo Kudo

Second Committee Member

Lee A. Woodward

Third Committee Member

J. Paul Fitzsimmons



Document Type


Included in

Geology Commons