USGS Contributions to the Climate Change Science Program

Eolian (wind-blown) deposits are both a blessing and a curse: they contain a valuable record of past climate changes but are deposits that could be reactivated in the future, with serious consequences for the natural resources, food supply, infrastructure, and wildlife of the country. This project researches the records of climate change in eolian deposits of the U.S. and assesses the potential for renewed activity of wind-blown sediments.

The objectives of this study are:

1. to test hypotheses about the role of dust in climate change;
2. to investigate records of natural climate variability in loess (dust) deposits;
3. to understand the processes responsible for sand dune activity in the U.S.; and
4. to assess the potential for reactivation of stabilized sand dunes in the U.S. under changing conditions of climate and land use.

The approach used in this study of windblown sediments is to examine stratigraphic sections where detailed records of past climate change can be found. Sediments are analyzed for their age, composition and source materials. In assessing the potential for future reactivation of eolian sediments, study is made of (1) modern eolian sands that are active now and the environmental factors that favor such activation, and (2) study of past geologic periods when eolian sands were active.

The areas of study for the project include the Central Lowlands (Midwest), the Great Plains, the western United States, and Alaska. Some cooperative work has also been done with the Geological Survey of Canada in the Prairie Provinces of Canada.

These cedar-covered hills near North Platte, Nebraska are glacial-age dust deposits. They are thicker and accumulated faster here than anywhere else in the world. Project researchers have new evidence that the huge dust clouds from this period kept the climate cool after the last glacial period ended, showing the importance of dust to climate change.

Sand dunes and eolian sheet sands are widely distributed over the southwestern United States, particularly in the southern Great Plains and the southwestern deserts and high plateaus. In the driest parts of the southwest, there are areas of active sand dunes, but most parts have dunes that are stabilized by vegetation and the sand is not moving at present.

The biggest impacts of active sand dunes in the Colorado Plateau region would be on the Navajo and Hopi people, whose reservation land is either on, or downwind of, the largest areas of sand dunes. Many Navajo and Hopi homes are on or near sand dunes; reactivation of dunes would obviously have a negative effect on living conditions. Sheep and cattle are important to the economy of the Navajo and Hopi, and much of the vegetation required for grazing is dune vegetation. In addition, dry farming is practiced in much of the area, some of it on sand dunes. Thus, reactivation of sand dunes in the area would have serious impacts on living conditions, grazing, and farming.