Aeolian Modifications of Glacial Moraines at Bishop Creek, Eastern California

Abstract

Aeolian landforms and deposits are important sources of paleoclimatic data, especially when associated with other climate controlled landforms. Aeolian activity has modified Pleistocene glacial moraines at Bishop Creek, California, through the deposition of dust, tephra, and sand on moraine surfaces and the abrasion of till boulders. Many moraine surfaces are mantled by 1 to 20 cm of Holocene age aeolian dust. The magnitude of the aeolian modifications to the moraines appear to vary over small distances in response to the complex topography. Dust influx influences pedogenesis and rock weathering significantly. The spatial variation of dust deposits is superposed on the chronosequence of glacial moraines and confounds expected weathering and pedologic trends. Ventifact populations formed ~15–22 ka and ~60–65 ka reveal that aeolian erosive activity is associated with full and retreating glacial conditions. Before chronosequence research is conducted on dryland landforms, site to site variability in aeolian influence must be analyzed to assess constancy in affects.