Ghost-dune hollows of the eastern Snake River Plain, Idaho: Their genesis, evolution, and relevance to Martian ghost-dune pits

Ghost-dune hollows on the eastern Snake River Plain (ESRP), Idaho, USA, are topographi-cally inverted, crescent-shaped depressions that record the partial encasement of sand dunes by ca. 61 ka basalt lava flows. Deflation of these ghost sand dunes produced approximately two dozen, 5-10-m-deep ghost-dune hollows now incompletely filled with pedogenically al -tered eolian and colluvial sediment. Optically stimulated luminescence (OSL) and 40Ar/39Ar ages constrain a ghost-dune hollow model that illuminates the late Pleistocene to Holocene environmental and climate history of the ESRP. Detrital zircon analyses indicate sand-dune supply routes changed following the burial of Pleistocene Henrys Fork (tributary of the Snake River) alluvium by ca. 70 ka basalt flows. Removal of Henrys Fork alluvium from the eolian supply system made Lake Terreton sediment the primary source for later ESRP sand dunes. Such sediment supply changes highlight the potential impacts of effusive volcanism on sand-dune histories and landscapes. Our results support stratigraphic and sedimentary modeling of comparable ghost-dune pit deposits older than ca. 2 Ga on Mars that may have served as refugia for early life on that planet. Analogous ancient ghost-dune hollow deposits on Earth may also have served as early life refugia.

Automated summary

Research on ghost-dune hollows on the eastern Snake River Plain in Idaho, USA, reveals insights into the late Pleistocene to Holocene environmental and climate history. Changes in sand-dune supply routes following effusive volcanism highlight the potential impacts on sand-dune histories and landscapes. This study supports the potential role of ancient ghost-dune hollows as refugia for early life on both Earth and Mars.