Winds of Change: Perspective on Ancient Eolian Sedimentology - Past, Present and Future

Our knowledge of ancient eolian deposits has developed over decades, yet the most significant advances may be yet to come. Desert deposits were sometimes thought to be lifeless, and perhaps useless, but it is now apparent that deserts are valuable, sensitive recorders of environmental change.

The seminal study of Hunter (1977) clarified 3 types of internal stratification to unequivocally distinguish eolian cross bedding from subaqueous bedding. Numerous studies of eolian deposits have covered: geometries and stratification, bounding surfaces, facies and depositional environments/subenvironments, interactions with extradunal environments, erg development and modifications (e.g., transgressions), fluid dynamics, wind tunnel experiments, computer modeling, cyclicity, sequence stratigraphy, paleoclimate, paleogeography, reservoir quality, and diagenesis.

More recognition of biota (e.g., petrified wood), trace fossils (e.g., dinosaur tracks and insect traces), and soft-sediment deformation/liquefaction features, add to our understanding of episodic and wet events in eolian history. We need new advances on dating to improve correlation and time resolution in these non-marine deposits.

Emerging studies will be: 1) the role of microbes in weathering of eolian sandstones; 2) records of extraterrestrial impacts at bed scales down to shocked quartz grains; and 3) spectacular remote images of Mars showing ancient eolian deposits, and current wind features resurfacing parts of the planet. The quest to understand wind processes on Mars will invigorate continuing studies and bring winds of change to our perspective of eolian processes on Earth and in our solar system.