The central united states is covered with extensive deposits of loess. where could this loess come from?

Glacier deposits--glaciers passed over the central part of the US creating flat land areas with mineral and dirt deposits. 

Loess are sediment deposits accumulated over thousands of years. those in the Midwest of the US are likely from glaciers passing over and leaving behind sentiment as they melted. 

arbology is the study of modern refuse and trash as well as the use of trash cans, compactors and various types of trash can liners. As an academic discipline it was pioneered at the University of Arizona and long directed by William Rathje.The project started in 1973, originating from an idea of two students for a class project. It is a major source of information on the nature and changing.

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