Second-day road log: From Quemado Lake to Mangas Mountains, Omega, Quemado, Tejana Mesa and Red Hill, New Mexico and Springerville and Alpine, Arizona
— Steven M. Cather, Richard M. Chamberlin, William C. McIntosh, James C. Witcher, James C. Ratte, and Orin J. Anderson

Today's route traverses part of the northwestern margin of the late Eocene to late Oligocene Mogollon-Datil volcanic field in west-central New Mexico and eastern Arizona. Volcanic and sedimentary rocks of late Cenozoic age are also exposed along the field-trip route and will be discussed.

The route begins with a scenic loop through the Mangas Mountains. Stop 1 is an overlook area along US-60 west of Omega, where we will discuss petroleum exploration and regional seismic reflection profiles in the Mangas-Alegres Mountain area, and the hydrology of the Largo Creek drainage basin. At Stop 2 we will visit a fissure vent at El Porticito near the south end of Tejana Mesa to discuss the geochemistry and petrology of upper Tertiary volcanic rocks near Quemado and the planned coal mine east of Tejana Mesa. Quemado crater, a Quaternary maar/cinder cone complex just south of US-60 near Red Hill, is Stop 3 and the lunch stop. There we will discuss the volcanology of the crater and role of faults and fractures in the localization of late Cenozoic volcanoes in the region. Stop 4 is on the Alpine Divide north of Alpine, Arizona, where we will discuss the recent Alpine I/Federal corehole and regional heat flow. After Stop 4, we will travel south to Alpine, Arizona to end the day's tour. Much of the geologic information presented here is from reconnaissance studies by Chamberlin et al. (1994b).