Geosciences and Environmental Change Science Center
The word "eolian" (or "aeolian" as spelled in many countries) comes from the Greek "Aeolus." Aeolus, in Greek mythology, was the god of the winds. "Eolian" thus refers to any process of sediment entrainment, transport and deposition by wind. Study of eolian processes and sediments is a part of the disciplines of geomorphology, sedimentology and paleoclimatology.
Eolian sediments fall into three broad categories: eolian sand, loess, and airborne dust:
Eolian sand is the coarsest particle size (>50 microns (µm)) and on the landscape forms dunes or relatively flat deposits called sand sheets. Large fields of active sand dunes are usually found in arid climates.
Many semiarid climates have stabilized (vegetated) sand dunes that may have been active in a climate of the past and may become active again in the future.
Loess is a geologic deposit composed dominantly of silt-sized (50-2 µm) particles, which are smaller than sand. Loess has the texture of flour or talcum powder. Loess usually forms thick blankets of material (some many tens of meters thick) over hundreds of square kilometers of landscape. It is the uppermost geologic deposit in the Midwest, Great Plains and northwestern United States, central and northern China, Europe, Argentina, and New Zealand. Loess, over time, forms very fertile soils which are important for agriculture. Ancient soils buried in loess deposits can tell us a great deal about past climates.
Airborne dust is composed of particles that are very small, almost always less than 20 µm in diameter, and usually less than 2 µm. Airborne dust can travel thousands of kilometers and can even travel intercontinental distances. Dust from desert regions can be deposited in the oceans, into humid tropical or midlatitude ecosystems and soils, and on top of high-altitude mountain ranges.
|Figure 4: Dust storm off the west coast of Africa, April, 2006. This is the same dust storm visible on the ground in the Canary Islands, shown in Fig. 3b. [courtesy of NASA/GSFC/MODIS Rapid Response Team] See a larger view.|
The objectives of this project are:
Task 1, Eolian sand: to understand the processes responsible for sand dune activity in the U.S. and to assess the potential for reactivation of stabilized sand dunes in the U.S. under changing conditions of climate and land use
Task 2, Loess: to investigate records of natural climate variability recorded in loess deposits
Task 3, Airborne dust: to test hypotheses about the role of dust in climate change and to assess the importance of far-traveled, airborne dust in soil formation
See the members of the project.
Our project was supported by the Earth Surface Dynamics Program of the Geologic Discipline of the USGS.