DEFLECTION OF RIO SALADO TERRACE SURFACES DUE TO UPLIFT OF THE SOCORRO MAGMA BODY, SOCORRO, NEW MEXICO

Abstract

The Socorro magma body is located in central New Mexico along the intersection of the Socorro fracture zone and the Rio Grande rift. The inflation rate of the magma body has been approximated at 2 to 4 mm/yr, based on leveling data by Larsen and others (1986) and InSAR data by Fialko and others (2001). This is a rapid rate that will impact the landscape evolution of the nearby Rio Salado drainage. The focus of this study is to evaluate the rate and amount of stream terrace deflection due to uplift of the magma body. Perturbations of the fluvial system act to offset stream terrace surfaces. The area of maximum uplift is localized. Both the Rio Grande and Rio Salado traverse this zone. Comparison of the modern stream profile with the paleostream profiles (indicated by the fluvial terraces) will show increasing deflection across the zone of maximum uplift. Preliminary examination of the Rio Salado drainage indicates that there are four terraces. Soils will be used to correlate and to estimate the ages of the terraces, based on the degree of CaCO 3 accumulation. This study will constrain the relative ages of the surfaces, determine the degree of uplift and form the basis for numeric age dating of the terrace surfaces.