HR: 1340h
AN: T43C-1334    [Abstracts]
TI: Rootless Mountains and Gravity Lows in the Sangre de Cristo Mountains, Southern Colorado-Northern New Mexico
AU: * Trevino, L
EM: trevino@geo.utep.edu
AF: University of Texas at El Paso, 500 W. University Ave., El Paso, Tx 79968 United States
AU: Keller, G R
EM: keller@geo.utep.edu
AF: University of Texas at El Paso, 500 W. University Ave., El Paso, Tx 79968 United States
AU: Andronicos, C
EM: chris@geo.utep.edu
AF: University of Texas at El Paso, 500 W. University Ave., El Paso, Tx 79968 United States
AU: Quezada, O
EM: quezada@geo.utep.edu
AF: University of Texas at El Paso, 500 W. University Ave., El Paso, Tx 79968 United States
AB: Gravity lows over large portions of the Sangre de Cristo Mountains of the southern Rocky Mountains are a geophysical curiosity. Two very low gravity anomalies in the continental United States are found in southern Colorado, in the San Juan Mountains and in the Colorado Mineral belt. Gravity modeling implies that these gravity lows may be attributed to granitic batholiths emplaced at a shallow depth. However, low gravity anomalies along the Sangre de Cristo Mountains cannot be attributed to subsurface batholiths. The Sangre de Cristo Mountains are largely composed of Proterozoic basement and Paleozoic sedimentary rocks. Exposed and uplifted, this presumably dense, Proterozoic basement in the Sangre de Cristo Mountains should be associated with gravity highs, but this is not the case. In this study, we focused on two gravity lows in northern New Mexico-southern Colorado. One is centered over the Sangre de Cristo Mountains in Colorado and northernmost New Mexico, and the other is located near Mora, New Mexico. The northern low can be attributed to Precambrian rocks being thrust over less dense Paleozoic rocks resulting in a rootless basement. In the Mora area, the low is attributed to unusually low-density Precambrian granitic rocks (the 1.68 Ga Guadalupita pluton) underlying a thick sequence.
DE: 8100 TECTONOPHYSICS
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting