Lethal Sandslides from Eolian Dunes

Authors

David B. Loope, University of Nebraska, LincolnFollow
Joseph A. Mason, University of Nebraska, Lincoln
Lowell Dingus, American Museum of Natural HistoryFollow

Document Type

Article

Date of this Version

1999

Comments

Published in The Journal of Geology, 1999, volume 107, p. 707–713. Copyright 1999 by The University of Chicago. Used by permission.

Abstract

Fossil vertebrates entombed within the Upper Cretaceous Djadokhta Formation of southern Mongolia bear testimony to a heretofore unknown geologic phenomenon: mass wasting of eolian dunes during heavy rainstorms. Evaporation of shallow-penetrating rainwater led to progressive calcite accumulation in a thin layer of sand about 0.5 m below the surface of dune lee slopes. During rare heavy rainstorms, a perched water table developed at the top of calcitic zones. Positive pore water pressure led to translational slides and fast-moving sediment gravity flows that overwhelmed animals on the lee slopes of large dunes and in interdune areas.