Probing Complex Crustal Structure Across the South-Central United States Using Receiver Functions and Autocorrelograms

Abstract

Here we model crustal structure across a profile in the south-central United States extending from the Gulf of Mexico to northern Arkansas by jointly modeling P receiver functions and autocorrelograms. Interfaces visible in the P receiver functions vary across the profile. Beneath the Gulf Coastal Plain we find an intra-sedimentary contact, the basin bottom, and the Moho. Beneath the Ouachita Mountains two impedance contrasts are visible, as well as the Moho. In the Arkoma Basin, the basin bottom and Moho are visible. At the northern end of the profile only the Moho is visible. We observe basin depths of 0–13 km, and a Moho depth ranging from ∼26 to 47 km, with the Moho deepening to the north and shallowing to the south. We also observe faster crustal P velocities south of the Ouachita Mountains and slower values to the north, potentially reflecting changes in bulk crustal composition.