Quaternary geologic map of the Winnipeg 4° × 6° quadrangle, United States and Canada

The Quaternary Geologic Map of the Winnipeg 4° × 6° Degree
Quadrangle, United States and Canada, is a component of the U.S.
Geological Survey Quaternary Geologic Atlas of the United States map
series (Miscellaneous Investigations Series I-1420), an
effort to produce 4° × 6° Quaternary geologic maps, at
1:1 million scale, of the entire conterminous United States and
adjacent Canada. The map and the accompanying text and supplemental
illustrations provide a regional overview of the
areal distributions and characteristics of surficial deposits and
materials of Quaternary age (~1.8 Ma to present) in parts of
North Dakota, Minnesota, Manitoba, and Saskatchewan. The map is not a
map of soils as soils are recognized in agriculture.
Rather, it is a map of soils as recognized in engineering geology, or of
substrata or parent materials in which agricultural soils are formed.
The map units are distinguished chiefly on the basis of (1)genesis
(processes of origin) or environments of deposition: for example,
sediments deposited primarily by glacial ice (glacial deposits or till),
sediments deposited in lakes (lacustrine deposits), or
sediments deposited by wind (eolian deposits); (2) age: for example,
how long ago the deposits accumulated; (3) texture (grain size)of the
deposits or materials; (4) composition (particle lithology) of the
deposits or materials; (5) thickness; and (6) other physical,
chemical, and engineering properties. Supplemental illustrations show
(1) temporal correlation of the map units, (2) the areal
relationships of late Wisconsin glacial ice lobes and sublobes,
(3) temporal and spatial correlation of late Wisconsin glacial phases,
readvance limits, and ice margin stillstands, (4) temporal and
stratigraphic correlation of surface and subsurface glacial deposits in
the Winnipeg quadrangle and in adjacent 4° × 6° quadrangles,
and (5) responsibility for state and province compilations.
The database provides information related to geologic hazards (for
example, materials that are characterized by expansive clay minerals;
landslide deposits or landslide-prone deposits), natural resources
(for example, sources of aggregate, peat, and clay; potential shallow
sources of groundwater), and areas of environmental concern (for example,
areas that are potentially suitable for specific ecosystem habitats;
areas of potential soil and groundwater contamination). All of these
aspects of the database relate directly to land use, management, and
policy. The map, text, and accompanying illustrations provide
a database of regional scope related to geologic history, climatic
changes, the stratigraphic and chronologic frameworks of surface and
subsurface deposits and materials of Quaternary age, and other
problems and concerns.