11 June 18
Previous work in the central Colorado Plateau has
identified patterns of river incision and topography that suggest a wave of very rapid incision passing through the region. Superimposed on this is local salt
deformation that has been unquantified. Parsing out the patterns and rates of regional incision and active salt deformation are a rich challenge. We have been using mapped stream terraces and basin-fill deposits dated by luminescence and cosmogenic-isochron-burial dating to quantify Quaternary incision, active faulting, and salt deformation along the Colorado River and its tributaries around the areas of Cataract Canyon, Moab, Spanish Valley, and Professor Valley.
In this presentation, I will focus on new results from
Jackson Rincon just downstream from Moab, and from Spanish Valley and Moab City itself.
Results identify a wave of incision passing through the system over middle-late Pleistocene time, while being linked to rapid faulting and subsidence in Moab City. It should be no surprise that youthful, transient incision is a hallmark of Utah’s canyonlands, which has, in turn, set off active salt deformation. Yet, the source for such recent baselevel fall in the central
Colorado Plateau remains a mystery.