Pre-Wisconsin Glaciation of Central North America
Work Group on Geospatial Analysis of Glaciated Environments (GAGE)
GAGE or INQUA
INQUA Commission on Glaciation
The work group on Geospatial Analysis of Glaciated Environments
(GAGE) has undertaken a project to compile a GIS database
and produce maps on the glaciated region south of the Wisconsin ice limit,
in the central United States. This project is conducted in cooperation with
a sister work group on Extent and Chronology of Glaciation (worldwide).
Both groups function within the INQUA Commission on Glaciation.
The Wisconsin and Illinoian glacial stages are still accepted and widely
used for glacial stratigraphy and correlation in North America and
elsewhere. However, the Kansan and Nebraskan are no longer considered
valid glacial stages in light of much evidence for more complicated
pre-Illinoian glaciation of the central United States (Richmond & Fullerton
1986). Hallberg's (1986) early and middle Pleistocene stratigraphy for Iowa
and Nebraska now serves as the standard for the region. More recently, Aber (1991)
proposed a revision for glaciation in northeastern Kansas.
This phase of ice-sheet advance is now called the Independence Glaciation,
dated 600,000 to 700,000 years ago. A minimum age for pre-Illinoian glaciation
of the Missouri basin has been provided recently by radiometric dating of glacial
pavement on Sioux Quartzite bedrock in southwestern Minnesota, 575±57 thousand
The Glacial map of the United States east of the Rocky Mountains
(Flint et al. 1959) displays the distribution of glacial deposits
and related features in the central United States, as they were known and
interpreted in the 1950s. Little attempt has been made during the past
four decades to revise or update this map in spite of much new information
concerning glaciations of this classic region. This project represents
application of new methods--geographic information systems
(GIS)--for compiling and producing a synthesis map of glacial features in
the central North America.
GIS data entry is completed for the region from Illinois to North
Dakota: latitude 37-49°N, longitude 87-104°W. Glacial features
have been derived from various published and unpublished sources-see source references. The glacial features have been combined
with digital line graphs (basic geography) and digital elevation models (basic
topography). A classification and ID code system has
been developed for glacial phenomena. GIS data entry, editing, and map production
took place at the GeoSpatial Analysis Laboratory,
Emporia State University, Kansas, USA.
The ultimate goal is to publish comprehensive maps and reports on
pre-Wisconsin glacial phenomena in the central United States. Many individuals
have sent information, volunteered to help compile data, or reviewed map
products--see map contributors.
For further information about this project, contact James S. Aber, firstname.lastname@example.org.
- Overview map
north-central United States. Clickable for nine detailed regional maps.
- Abstract of
Pre-Illinoian glacial geomorphology and dynamics in the central United States,
west of the Mississippi (Aber 1999).
Last update: 6 Jan. 2000.
- Aber, J.S. 1991. The glaciation of northeastern Kansas. Boreas
- Aber, J.S. 1999. Pre-Illinoian glacial geomorphology and dynamics in the central
United States, west of the Mississippi. Geological Society of America, Special Paper
337, p. 113-119.
- Flint, R.F., Colton, R.B., Goldthwait, R.P. and Willman, H.B. 1959. Glacial
map of the United States east of the Rocky Mountains. Geological Society
- Hallberg, G.R. 1986. Pre-Wisconsin glacial stratigraphy of the Central
Plains region in Iowa, Nebraska, Kansas, and Missouri. Quaternary Science
- Richmond, G.M. and Fullerton, D.S. 1986. Summation of Quaternary
glaciations in the United States of America. Quaternary Science Reviews