Surficial deposits and materials in the eastern and central United States (east of 102 degrees west longitude)

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Description The surficial geologic map of the Eastern and Central United States depicts the areal distribution of surficial geologic deposits and other materials that accumulated or formed during the past 2+ million years, the period that includes all activities of t
Originators Fullerton, David S.; Bush, Charles A.; and Pennell, Jean N.

Related topics

States or counties

Geologic unit (described by ussurfm020.pat or surfpoly.shp)

The map is a surficial materials map. Deposits and residual materials are distinguished in part on the basis of particle size or texture, particle lithology or composition, and other physical, chemical, and engineering characteristics. It is not a map of soils that are recognized in agriculture, agronomy, or pedology. Rather, it is a generalized map of soils as recognized in engineering geology, or of substrata or parent materials in which agricultural soils are formed. Several classification systems for engineering and agricultural soils are in use, and terminology differs. The textural or particle size divisions (e.g., clay, sand, pebbles, boulders) and the matrix nomenclature (e.g., loamy sand, clay loam, silty clay) of the U.S. Department of Agriculture are used here to ensure uniformity of terminology.

Label Definition
Geounit Two digit letter symbol for the map unit description
Color The shade pattern number from the Arc/Info shadeset color524.shd.
R Percentage of red used to produce map unit colors.
G Percentage of green used to produce map unit colors.
B Percentage of blue used to produce map unit colors.

Rock or geologic deposit boundary line (described by ussurfm020.aat or surfarcs.shp)

Line separating different geologic units.

Label Definition
Ltype The type of geologic boundary code.

Glacial limit line, without line decorations (described by glacal020.aat or glacal.shp)

A line showing the southern limit of glaciation in the United States at various times.

Label Definition
Ltype The lines of the glacial limits were compiled with the surficial polygons. Only one item, ltype, was used. The item value indicates the geologic time period associated with each position of maximum glacial advance.