Eolian-fluvial interaction in the Page Sandstone (Middle Jurassic) in south-central Utah, USA — a case study of erg-margin processes
Citation
Ronald C Blakey, and Lawrence S Jones, Eolian-fluvial interaction in the Page Sandstone (Middle Jurassic) in south-central Utah, USA — a case study of erg-margin processes: .
Summary
Channel- and lens-shaped deposits of non-eolian red sandstone are enclosed within the eolian Leche-e Member of the Page Sandstone in south-central Utah. Detailed analysis of lithology and geometry, and regional correlation of the red sandstone deposits suggests that the channel-shaped scours and in-filling deposits were formed by ephemeral stream processes, in contrast to earlier interpretations that suggested a marine estuarine origin. We hypothesize that ephemeral streams transporting volcanic debris flowed toward the north and northeast along the western edge of the Page erg. Local avulsion, possibly caused by eolian damming of an adjacent drainage, led to stream flow into low areas of the Page erg. Entrainment of loose eolian sand, [...]
Summary
Channel- and lens-shaped deposits of non-eolian red sandstone are enclosed within the eolian Leche-e Member of the Page Sandstone in south-central Utah. Detailed analysis of lithology and geometry, and regional correlation of the red sandstone deposits suggests that the channel-shaped scours and in-filling deposits were formed by ephemeral stream processes, in contrast to earlier interpretations that suggested a marine estuarine origin. We hypothesize that ephemeral streams transporting volcanic debris flowed toward the north and northeast along the western edge of the Page erg. Local avulsion, possibly caused by eolian damming of an adjacent drainage, led to stream flow into low areas of the Page erg. Entrainment of loose eolian sand, combined with fluid loss via infiltration, led to a rapid increase in sediment/fluid ratio during flow events, initially resulting in sandy debris flow deposition. Subsequent floods entrained less material from the underlying, more cohesive, debris flow deposits, had a lower sediment/water ratio, and hence left deposits containing some evidence of flow turbulence. Eventually, stream drainage avulsed again, probably back to a more northerly course into the Carmel sea, fluvial deposition within the erg ceased, and eolian deposits covered the now intercalated fluvial complex.
Published in Sedimentary Geology, volume 109, issue 1-2, on pages 181 - 198, in 1997.
