6466 15 archive 12 disk0/00/00/64/66 2008-07-29 18:46:31 2008-07-29 18:46:31 2008-07-29 18:46:31 techreport show Although during much of its geologic history Iowa was part of an interior sea, today what we see on the land surface has been heavily influenced by recent glaciation. Everything from Iowa soils, rivers, lakes, and hills has been influenced by glaciation. Most of Iowa’s bedrock is hidden beneath a thick mantle of deposits from the Cenozoic (i.e., new life) Era, spanning the last 65 million years. Geologists have divided the Cenozoic Era into two periods. These are the Tertiary (1.8-65 million years ago) and Quaternary Periods (recent to 1.8 million years ago). Most geologic records in Iowa are from the Quaternary period, and include glacial till and loess. Natural_Resources_Department_of RAGBRAI, DNR, Landscape UF R MK 2008-07-22 public 6314 5 6466 1 pdf en public

2008day3.pdf

2008day3.pdf 1400768 http://publications.iowa.gov/6466/1/2008day3.pdf