AN INTEGRATED STUDY OF THE RIO GRANDE RIFT’S JORNADA DEL MUERTO BASIN IN SOUTH-CENTRAL NEW MEXICO UTILIZING REMOTE SENSING AND GEOPHYSICAL METHODS

The Rio Grande rift is a lithospheric-scale feature that follows a broad topographic high that includes the southern Rocky Mountains. Since being recognized as an important continental rift in the 1970’s, this feature has been the object of considerable interest and study. The northern portion of this feature forms a classical physiographic rift valley and structurally consists of a series of interconnected, asymmetrical grabens extending from Leadville, Colorado to Socorro, New Mexico. South of Socorro, New Mexico, the rift widens into at least two major parallel rift structures that flank the Jornada del Muerto basin. Initial studies of this basin, utilizing satellite imagery (Landsat 7 ETM+), were done to identify the archaeological trail the Camino Real Tierra Adentro. Further analysis of remote sensing data gave detailed views of the structure and lithology of the bounding mountain ranges of the Jornada del Muerto. When combined with USGS Digital Elevation Maps (DEM’s), a three-dimensional view of the basin can be constructed. The 3-D model illustrates the apparent synclinal structure of the Jornada del Muerto basin. However, analysis of gravity data reveal a complex basinal structure with deep sub-basins being located at the southern and northern ends of the basin. When gravity and satellite imagery are combined, the locations of these sub-basin anomalies can be located and associated with the local geology. The merging of the gravity and satellite imagery was done using the GIS system ArcView and ArcInfo. Utilizing the GIS system we are able to view, all at once, digitized geological data, gravity data, remote sensing data and well log data, which helped identify true thickness of basin fill and in some wells, the depth of the Precambrian basement. Some industry seismic data in the basin shows interesting structures revealing that both Laramide and rift tectonics contributed to the formation of the basin and are the cause of the observed gravity anomalies.