Smith Canyon dune field, Washington, USA: relation to glacial outburst floods, the Mazama eruption, and Holocene paleoclimate

Sedimentary deposits from the Smith Canyon dune field, south-central Columb ia Basin, Washington, U.S.A, document climatically-influenced Late Pleistoc ene and Holocene aeolian and fluvial deposition in a region impacted by gla cial outburst floods and tephra falls. The depositional history is summariz ed by five environmentally distinctive and climatically sensitive sedimenta ry units (temporal limits estimated): Unit 1 (c. 15.5-8 ka), pedogenically altered glacial outburst flood and minor aeolian silt and clay; Unit 2 (c. 8-6.9 ka), fluvial and minor aeolian sand; Unit 3 (c. 6.9-6.8 ka), flood-in duced fluvial sand with gravel-sized tephra clasts; Unit 4 (c. 6.8-3.9 ka), aeolian dune sand; Unit 5 (c. 3.9 ka to present), pedogenically altered, s tabilized dune sand. Estimated age ranges are based on stratigraphic positi on, tephrochronology, and correlation with temporally constrained strata fr om elsewhere in the region. (C) 2001 Academic Press.