High Resolution, Ground-Based Magnetic Surveys Over Exposed and Buried Tertiary Intrusions within Laramide Folds and Faults, Big Bend Region, TX
Although previous high resolution aero-magnetic surveys (e.g. Scott, 2004; Drenth and Finn, 2007) reveal several exposed and unexposed intrusions in the surrounding area, these surveys were typically performed at a 400m flight-line elevation, which does not provide enough resolution to delineate the small-scale, structures of our study. Furthermore, these high-resolution aeromagnetic surveys do not extend to our map area. We present high resolution, ground-based magnetic data which helps us to constrain cross cutting relationships of potentially folded and/or faulted intrusive bodies. We present data as well as results of modeling the magnetic data to test and refine interpretations of relative timing between intrusions and structures.
Dagger Mountain is a NW-striking anticlinal box fold x km SW of Dog Canyon. Maxwell and others (1967) suggested Dagger Mountain might be cored by a laccolith while Moustafa (1988) interpreted DM folds to be caused by a blind thrust within a zone of convergent wrench faulting. Alternatively, post-Laramide laccolith may have preferentially intruded into and warped a Laramide fold, similar to the way the Solitario laccolith deformed the Terlingua-Fresno monocline. Several magnetic profiles as well as structural data will test these hypotheses.