Coal maturation and geothermal history, west-central New Mexico
— Jeffrie Minier and Marshall Reiter

Coal maturation data from five regions in west-central New Mexico near the southern boundary of the Colorado Plateau exhibit a relatively uniform level of thermal maturation. While variance (nested ANOVA) and "F" test analyses indicate a relatively minor increase in thermal maturation from the southern San Juan Basin and Gallup regions to the Salt Lake region, which is located in the volcanically-active Jemez lineament, thermal burial history analyses show that differences in maturation levels between the various regions may be due to differences in coal ages, burial depths and/or background heat flow. Model results suggest an average coal burial depth of about 1 km or slightly greater. The effect of recent intrusive activity in the study area on coal maturation is expected to be minimal. The lack of a definite increase in coal maturation across the study area allows several possible suggestions to be made with respect to the Colorado Plateau-Basin and Range province (Datil-Mogollon subprovince) transition. If the transition occurs in the study area, then thermal processes are either deeper, younger or more localized (smaller and widespread) than in the Colorado Plateau- Basin and Range province transition along the northwestern periphery of the Plateau. Alternatively, if largescale thermal events have been occurring in the upper mantle and crust, they are doing so sufficiently south of the study area that the thermal influence has not been observed.