Bedrock topography of northwest Iowa

IMAP 1726
By:  and 



Bedrock in Iowa (Hershey, 1969) generally is overlain by deposits of glacial drive and alluvium. The drift, consisting of glacial till and glacial outwash, ranges in thickness from zero to more than 500 feet in western Iowa; the alluvium in stream valleys ranges in thickness from less than 1 foot to more than 70 feet. The configuration of the bedrock surface is the result of a complex system of ancient drainage courses that were developed during a long period of preglacial erosion. This map, for a 12 county area in west-central Iowa, is the eighth in a series of nine reports that will provide statewide coverage of the bedriock topography of Iowa. 

Study Area

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Bedrock topography of northwest Iowa
Series title IMAP
Series number 1726
DOI 10.3133/i1726
Year Published 1986
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Iowa Water Science Center
Description 2 Plates: 32.96 x 42.09 inches and 31.49 x 42.41 inches
Country United States
State Iowa
Scale 25000
Online Only (Y/N) N
Additional Online Files (Y/N) N