Physical Sciences and Mathematics Commons^™

The Jurassic Todilto Formation Of New Mexico, Henry O. Ash

Earth and Planetary Sciences ETDs

The Todilto formation of New Mexico is a widespread and distinctive Jurassic unit confined to the northern one-half of the State and adjacent parts of Arizona and Colorado. It consists of a lower Limestone member and an upper Gypsum member. The Gypsum member also contains some limestone. The two members are not coextensive in area. Both are present in the central part of the area in which the formation is found, but the Limestone member extends far beyond the limits of the Gypsum member.

Geology Of The Southern Part Of The Ortiz Mountains Santa Fe County, New Mexico, John W. Peterson

Earth and Planetary Sciences ETDs

The Ortiz Mountains lie in a belt of early Tertiary intrusive centers adjacent to the Rio Grande depression of north-central New Mexico. Tertiary organic activity and subsequent erosion have etched this mountain group into considerable relief.

Intrusive activity occurred during early Tertiary Espinaso time and resulted in emplacement of sills and dikes of a central stock. Correlation of volcanism with intrusive phases is difficult. Most volcansim probably occurred during the later part of Ortiz igneous activity. An elongate vent is exposed in the eastern part of the mountains and structurally occupies the highest position in the group.

The principle igneous …

Geology Of The Northern Part Of The Ortiz Mountains, Santa Fe County, New Mexico, Otis M. Mcrae

Earth and Planetary Sciences ETDs

The northern part of the Ortiz Mountains of north-central New Mexico consists of a tilted fault block of Cretaceous Mancos shale and Mesaverde formation intruded by latite-andesite porphyry sills and laccoliths and a nepheline-bearing augite manzonite stock. Igneous activity started with the development of a volcanic vent in what is now the central part of the mountains. Volcanic debris from the vent want removed from the area by erosion and provided sedimentary material for the late [ ] Espinaso volcanics of the adjoining areas. Intrusion of the latite-andesite porphyry sills and laccolite followed extrusive igneous activity, as demonstrated by the …