CRUSTAL EXTENSION VARIATIONS ALONG THE RIO GRANDE RIFT, USA

The southern Rio Grande Rift (RGR) near the USA-Mexico border is thought to be extending at a higher rate than the central and northern RGR, and is more seismically active. In order to investigate the lithospheric and geothermal variations along the RGR, we will integrate seismic receiver functions, gravity, and magnetic data. To map crustal thickness variations, we will use the available broadband seismic data to calculate receiver functions that will be constrained with the available seismic refraction models. The available gravity and magnetic data will be used to create a variety of maps including those using enhancement techniques (e.g., wavelength filtering and derivatives) in order to interpret crustal structural features. Two-and one half dimensional (2.5D) gravity and magnetic forward models along three profiles constrained by the receiver function results will aid in determining the lithospheric variations along the RGR. Three-dimensional (3D) inversion of magnetic data and 2D power spectrum analysis along the RGR will be used along with heat flow data to deliver a clear picture of the geothermal structures and assist to compute Curie point depth (CPD) variations. Variations in the CPD will aid in determining regions with suppose high heat flow that might be related to higher extension rates. 3D inversion of gravity data that integrates existing geological and geophysical constraints will allow us to determine which features in the lithospheric crustal models are more resolved and be used to confirm the depths to the Moho, and crustal structural and sediment variations across the region. All the final models will be integrated and interpreted to determine the extent of crustal extensional rates along the RGR