Chaco Culture National Historic Park
This view is of Fajada Butte taken in morning light. Fajada Butte is an erosional remnant of sedimentary rock formations of Late Cretaceous age . The top of the butte consists of Cliff House Sandstone. The Cliff House Sandstone is subdivided into an Upper Sandstone member (the top cliffs of the butte), an intermediate sandstone and shale member (it erodes to form a bench and slope near the top of the butte), and a Lower Sandstone member (responsible for the massive cliff about midway up the butte). The Cliff House Sandstone overlies the Menefee Formation which is mostly covered by talus and soil on the lower portion of the slopes of Fajada Butte (Mytton and Schneider, 1987). The Cliff House Sandstone and Menefee Formations also crop out along the canyon rims of Mesa Verde in Colorado. Based on fossil ammonite species and other correlation methods, the age of the Late Cretaceous rock units exposed at Chaco have been determined to middle Campanian age (between 80 to 76 million years) (Molenaar and others, 2002; Penman, 2007).
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Last modified: 1/13/2011