HOLOCENE CLIMATE AND ENVIRONMENTAL CHANGE ON THE COLORADO PLATEAU

The Colorado Plateau contains a rich record of sedimentary archives of past climate and geomorphic change. Easy to erode sedimentary rocks have produced extensive Holocene alluvial fill and eolian dune deposits. These sequences have been extensively described and dated in tributaries to the Colorado River and plateaus in southern Utah. Compiled records suggest a millennial-scale pulsing of arroyo aggradation/entrenchment and eolian dune activation/stabilization in the region and suggest a link to hydroclimate change. Key time periods of geomorphic change include dune activity and channel aggradation in the middle Holocene (~6ka) and two time periods in the late Holocene (4-3 ka and 1-2 ka). These episodes of environmental adjustment and are roughly correlative with regional drought and hydroclimate variability, possibly linked to increased sediment supply from upland catchments. Regional geomorphic records and climate archives are presented and possible linkages to Holocene climate change are discussed.