Smith Canyon dune field, Washington, U.S.A: relation to glacial outburst floods, the Mazama eruption, and Holocene paleoclimate

Sedimentary deposits from the Smith Canyon dune field, south-central Columbia Basin, Washington, U.S.A. document climatically-influenced Late Pleistocene and Holocene aeolian and fluvial deposition in a region impacted by glacial outburst floods and tephra falls. The depositional history is summarized by five environmentally distinctive and climatically sensitive sedimentary 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-induced 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, stabilized dune sand. Estimated age ranges are based on stratigraphic position, tephrochronology, and correlation with temporally constrained strata from elsewhere in the region.