THIS DATA SET DOES NOT REPLACE the Quaternary Geology map of 1979.
Information contained in this data set is more generalized than the 1979 version. While the 1979 version is more detailed, it lacks recent updates to the lithostratigraphic reclassification of units which have been added to this 1996 version. These updates primarily affect Wisconsin materials in north eastern Illinois.
The data are not appropriate as a geodetic, legal or engineering base. The data set was not and is not intended as a substitute for surveyed locations, such as can be determined by a registered Public Land Surveyor. Although useful in a GIS as a reference base layer for maps, the data set has no legal basis in the definition of boundaries or property lines.
In April 2004 edition 1.0 of the data set was transitioned to storage in an Oracle RDBMS using the ArcSDE geodatabase model. The result (this version) is designated Edition 20040422.
Links to these are provided in the Cross References section.
Individuals or entities may make fair use of copyrighted ISGS material, such as reproducing a single figure or table, or using a brief text quotation, without obtaining formal permission, but in all cases the Illinois State Geological Survey must be credited as the source of the material. To reproduce ISGS information beyond the fair use standard, permission must be obtained from the ISGS Information Office, 615 East Peabody Drive, Champaign, Illinois 61820, 217-333-4747, email@example.com. License fees and a license agreement may be required, depending on the proposed usage.
Map information is to be used at a scientifically and cartographically appropriate scale, that is, at a scale no greater than indicated on the map or as described in the documentation of the map or map data. Map information is not appropriate for, and is not to be used as, a geodetic, legal, or engineering base. Map information has no legal basis in the definition of boundaries or property lines and is not intended as a substitute for surveyed locations such as can be determined by a registered Public Land Surveyor.
The data do not replace the need for detailed site-specific studies.
For QUAT79: This coverage was generated by Environmental Systems Research Institute as one component of a multi-layer Integrated Terrain Unit (ITU) database. Automation was limited to polygons with area of one square mile or greater and linear features greater than one-half mile in width. Boundaries which were generally coincident with boundaries of other ITU layers (e.g., soil associations or surface water bodies) may have been adjusted to be exactly coincident. Overlay with the published map shows significant differences in some areas. This data can only be used to show the generalized Quaternary boundaries within Illinois.
For MORAINES: Horizontal positional accuracy was verified in October, 1991 by manual overlay of source and hard-copy plots. Lines within one line-width of the source were deemed acceptable. Accuracy of the source with respect to the ground condition was not addressed in this review. Consult the source for such information.
GIS processing followed these basic steps: 1) Union of MORAINES and QUAT79 2) resel for codes that were moraines 3) group these according to parent material
The features were imported into the ISGS SDE enterprise database following steps outlined in ISGS procedure GISDB_0009.
Arc attributes: SYMBOL - archival code used for coverage maintenance 0 - Quaternary materials contacts 1 - Quaternary materials contacts 2 - moraines 922 - Quaternary materials contacts 993 - Quaternary materials contacts 999 - state boundary
CODE - archival code used for coverage maintenance 0 - arcs visible on B104 plate 1 - loess or other boundaries not visible on B104 plate
Polygon Attributes: SYMBOL2 - Numeric code for geologic deposits, for small scale generalizations 100 - Wisconsin or younger deposits 150 - end moraines of Wisconsin Episode 200 - deposits of Illinois Episode 999 - no or highly eroded glacial deposits 0 - uncoded
SYMBOL - Numeric code for geologic deposits, generalized by event 100 - Wisconsin glaciation 200 - Illinoian glaciation 300 - pre-Illinoian glaciation 700 - floodplain beyond glacial limit 800 - bedrock 900 - beyond known glacial extent
QDSYMBOL - Numeric code for stratigraphic classification 10 - Cahokia and/or Henry Formation 15 - Cahokia and/or Henry Formation 20 - Equality Formation 30 - Wedron Group (end moraine) 40 - Wedron Group (ground moraine) 50 - Winnebago Formation 60 - Glasford Formation 70 - Pearl Formation 80 - Wolf Creek Formation 90 - Paleozoic rock
QUATCODE - Alphanumeric code for geologic deposits, classified by material C1 - waterlain river sediment and wind-blown beach sand E1 - fine-grained sediment deposited in lakes M1 - diamicton deposited as till and ice-marginal sediment (Wisconsin Episode) GM1- diamicton deposited as till and ice-marginal sediment (Wisconsin Episode) I1 - diamicton deposited as till and ice-marginal sediment (Illinois Episode) I2 - sorted sediment including river and lake deposits and wind-blown sand P1 - bedrock; exposed of covered by loess and/or residuum
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Illinois Natural Resources Geospatial Data ClearinghouseGenerated by mp version 2.8.25 on Thu Apr 02 09:54:11 2009