New Mexico Geological Society Annual Spring Meeting — Abstracts

High-resolution aeromagnetic data has recently been used to effectively map fault traces in sedimentary basin settings. Aeromagnetic data collected by the U.S.O.S exhibits prominent magnetic anomalies along known and buried faults, explained by either (A) contrasting magnetic susceptibility of faults themselves or (B) syndeformational deposition of layers of anomalous susceptibility. Recent modeling has supported the latter of the two hypotheses.

We have obtained ground magnetic field surveys as a high-resolution tool for ground truthing in comparison to aeromagnetic surveys. A series of five lines were collected perpendicular to and across the Sand Hill Fault for this study using a cesium magnetometer. The Sand Hill Fault is a major down to the east, north-trending, normal fault on the northwestern boundary of the Albuquerque basin, well exposed in parts of the badlands topography in this area. Detailed mapping of the fault was combined with magnetic susceptibility information to produce geologically realistic models of the magnetic profiles. These preliminary models generally support conclusions similar to those for aeromagnetic data modeling: the magnetic anomalies result from broad magnetic features interpreted as depositional units, rather than a fault of anomalous magnetic properties. Implications for magnetic properties in relation to fault zone structure will be discussed.