Structural relationships in the Florida Mountains, southwestern New Mexico-A review
Jeffrey M. Amato
Despite several previous detailed structural investigations of the Florida Mountains, the nature of low-angle faults there remains controversial. Paleozoic sedimentary rocks lie in both fault contact and nonconformably over the Cambrian Florida Mountains pluton. All rocks are complexly faulted. The structural controversies in the region include (1) the relative importance of steep, basement-involved block faulting versus lowangle thin-skinned thrusts during the Laramide orogeny; (2) the relative importance of strike-slip versus reverse motion on the south Florida Mountains fault (SFMF); and (3) the validity of a thrust model that attempts to explain the younger-on-older relationships. Resolution of these controversies will require more detailed structural studies, particularly along the SFMF and other major structures, as well as thermochronologic investigations of the exhumation history of the Florida Mountains pluton on either side of the SFMF. An additional consideration is the possibility that these structures represent reactivation of normal faults formed during a regional Jurassic extensional event documented in other areas. Tertiary normal faulting resulted in tilting of the range –25° to the northeast. Perhaps several of the normal faults interpreted by other workers as forming during the Laramide event are in fact related to Tertiary Basin-and Range extension.
- Amato, Jeffrey M., 2000, Structural relationships in the Florida Mountains, southwestern New Mexico-A review, in: Southwest passage. A trip through the Phanerozoic, Lawton, Timothy F.; McMillan, Nancy J.; McLemore, Virginia T., New Mexico Geological Society, Guidebook, 51st Field Conference, pp. 103-108.