Tectonic history of the northern Rio Grande rift derived from apatite fission-track geochronology
— Shari A. Kelley and Ian J. Duncan

This study is concerned with the uplift history of the mountain ranges that bound the eastern margin of the Rio Grande rift in northern New Mexico (Fig. 1). The principal objectives of this paper are to present the results of fission-track dating of granitic rocks from three ranges on the eastern margin of the rift (Fig. 1), and to use these dates to infer the approximate timing and the rate of uplift and erosion in each range. These data are then used to place constraints on the paleogeographic evolution of northern New Mexico between the Late Cretaceous and the early Miocene. The paleogeography shows that the ranges on the eastern margin of the early rift were not as continuous along the length of the rift as the ranges observed today.