Simulating the Evolution of Fluid Underpressures in the Great Plains, by Incorporation of Tectonic Uplift and Tilting, with a Groundwater Flow Model

Figure 5

Distribution of Miocene and Pliocene sedimentary rocks (shaded) on the Eaton Alvarado ridge. These sediments lie in a chain of deep medial grabens (like in the Rio Grande rift in NM and southern CO) and in thin blankets on the flanking rises of the ridge. The region around the crest of the Alvarado ridge is outlined by a heavy solid line. The large continuous shaded area in the east, running from Nebraska down to the Texas Panhandle, is the Ogallala Formation (Figure  4 of [11]).