The description of map units and sources of information are both included as text files.
This database represents an attempt to digitally capture all the geologic information available on the published paper map. Separate coverages are provided for the map unit polygons, linear glacial features, point data for drumlins and type localities, important stratigraphic sections, and line coverages for the hydrology and topography.
The published maps of the Quaternary Geologic Atlas of the U.S. used three separate projections. To promote uniformity, the projection of this database was changed from Lambert Conformal Conic to Albers Equal Area and all subsequent digital databases will similarly be changed to Albers Equal Area Projection.
Illustrations are provided showing loess distribution and thickness, relationships of the late Wisconsin glacial lobes, sublobes, and advances within lobes and sublobes, and areas of responsibility for the compilation of the map. An illustration is provided showing the correlation of map units.
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Although this Federal Geographic Data Committee-compliant metadata file is intended to document the data set in nonproprietary form, as well as in ARC/INFO format, this metadata file includes some ARC/INFO-specific terminology.
The dataset for the Lake Superior quadrangle consists of 10 coverages. geo_net gla_lin gla_pnt hydr_lin topo_lin bnd_lin bnd_net rd_lin rr_lin grid_linThe dataset also includes an ARC/INFO AML, lineset, shadeset, and markerset that will produce the EPS file of the geology and glacial features and the list of map units.
Digitization and attributing of compilation: Digitizing contractor scanned source stable-base material, vectorized scan, attributed files, and produced check plots and coverages. C.A. Bush proofread check plots and reviewed digital files; made final corrections as needed; produced graphical files and imported them into graphics program to prepare plot file. C.A. Bush proofread cartographic product. C.A. Bush and C.E. Briles prepared illustrations and word processing files of descriptions of map units and sources of information. The original paper map was scanned and recreated as PDF files. (The original map was thoroughly reviewed for conformity with U.S. Geological Survey editorial standards and stratigraphic nomenclature.)
The geo_net.pat INFO file consists of the following items:
GEOCODE--Refers to the type of polygon and is one of the following: the map unit abbreviation, "lake", "island", or "river".
AGE--Refers to the age of the map unit and is one of the following: "Holocene", "Holocene and Late Wisconsin", "Late Wisconsin", "Early Wisconsin", or "Pre Wisconsin".
MORAINES--A modifier to the map unit indicating if the unit is a moraine and is one of the following: "Ground moraine", "Ground moraine under Lake Michigan", "Ground moraine under Lakes Michigan and Huron", "Ground moraine under Lake Superior", "End moraine", or "Attenuated drift".
MAP_UNITS--A description of the soils within the map units (see below).
MODIFIER--Indicates the names of rivers, lakes, or islands or indicates if a map unit is submerged.
COLOR--indicates the number of the shade unit in shadeset color524.shd used to fill the map units when plotted using the AML script superior.aml.
Items in geo_net.pat are defined as follows:
GEOCODE MAP_UNITS, (AGE) lm LAKE CLAY AND SILT UNDER LAKES MICHIGAN, HURON, AND SUPERIOR (HOLOCENE) lc LAKE SILT AND CLAY UNDER LAKES MICHIGAN, HURON, AND SUPERIOR (HOLOCENE) ls LAKE SAND AND GRAVEL UNDER LAKE SUPERIOR (HOLOCENE) al ALLUVIUM (HOLOCENE AND LATE WISCONSIN) hp PEAT AND MUCK (HOLOCENE AND LATE WISCONSIN) ed DUNE SAND (HOLOCENE AND LATE WISCONSIN) lds DELTA SAND (HOLOCENE AND LATE WISCONSIN) lga LAKE GRAVEL (HOLOCENE AND LATE WISCONSIN) lca LAKE SILT AND CLAY (LATE WISCONSIN) lsa LAKE SAND (LATE WISCONSIN) gg OUTWASH SAND AND GRAVEL (LATE WISCONSIN) kg ICE-CONTACT SAND AND GRAVEL (LATE WISCONSIN) tc CLAYEY TILL, Ground moraine (LATE WISCONSIN) tc CLAYEY TILL, Ground moraine under Lake Michigan (LATE WISCONSIN) tc CLAYEY TILL, End moraine (LATE WISCONSIN) tcr CLAYEY TILL, Attenuated drift (LATE WISCONSIN) tl LOAMY TILL, Ground moraine (LATE WISCONSIN) tl LOAMY TILL, Ground moraine under Lake Michigan (LATE WISCONSIN) tl LOAMY TILL, End moraine (LATE WISCONSIN) tlr LOAMY TILL, Attenuated drift (LATE WISCONSIN) td CALCAREOUS SANDY LOAMY TILL, Ground moraine (LATE WISCONSIN) td CALCAREOUS SANDY LOAMY TILL, Ground moraine under Lakes Michigan and Huron (LATE WISCONSIN) td CALCAREOUS SANDY LOAMY TILL, End moraine (LATE WISCONSIN) tdr CALCAREOUS SANDY LOAMY TILL, Attenuated drift (LATE WISCONSIN) tdb NONCALCAREOUS SANDY LOAMY TILL, Ground moraine (LATE WISCONSIN) tdb NONCALCAREOUS SANDY LOAMY TILL, Ground moraine under Lake Superior (LATE WISCONSIN) tdb NONCALCAREOUS SANDY LOAMY TILL, End moraine (LATE WISCONSIN) tdr NONCALCAREOUS SANDY LOAMY TILL, Attenuated drift (LATE WISCONSIN) ts SANDY TILL, Ground moraine (LATE WISCONSIN) tsr SANDY TILL, Attenuated drift (LATE WISCONSIN) tde SANDY LOAMY TILL (EARLY WISCONSIN) tlp LOAMY TILL (PRE WISCONSIN) tlq LOAMY TILL (PRE WISCONSIN)The geo_net.aat INFO file consists of the following items: LTYPE--Refers to the type of arc and is one of the following: "contact", "shoreline", "map boundary", or "null". Null is the imaginary line separating streams from lakes. ACCURACY--Refers to accuracy of location of arcs in the geo_net coverage and is either "certain" or "inferred".
The gla_lin coverage contains lines that represent linear glacial features. The gla_lin.aat INFO file consists of the following items: TYPE--Refers to the type of glacial feature described by the arc and is one of the following: "esker", "map boundary", or "limit of glacial advance". MODIFIER--Refers only to limits of glacial advance that are "interlobate". ACCURACY--Refers to accuracy of location of arcs in the gla_lin coverage and is either "certain" or "inferred".
The gla_pnt coverage contains points that represent drumlins, places where the direction of ice movement is indicated by striations, or the location of important stratigraphic sections. The gla_pnt.pat INFO file consists of the following items: TYPE--Refers to the type of feature shown at the point and is one of the following: "drumlin", "direction of ice movement", or the name of important stratigraphic sections. ANGLE--Refers to the direction of drumlin or ice movement; in degrees measured clockwise from north. MRKANGLE--Negative of ANGLE; useful for plotting symbols in ARCPLOT.
Hydr_lin is a line coverage created after scanning the hydrographic layer that was used in the original paper map. It has no user-defined attributes.
Topo_lin is a line coverage created after scanning the topographic layer that was used in the original paper map. It has no user-defined attributes.
Bnd_lin is a line coverage created from 1:2,000,000-scale U.S. Geological Survey Digital Line Graph coverages (DLG). It contains lines representing the U.S./Canada international boundary and state boundaries. The bnd_lin.aat INFO file contains the following item: TYPE--Refers to the type of line and contains the values: "state boundary", "international boundary", or "map boundary".
Bnd_net is a polygon coverage created from 1:2,000,000-scale DLG coverages and contains political and administrative boundaries. To decrease the size of the coverage, all user-defined attributes have been removed except "STATE_NAME" and "AREA_NAME".
Rd_lin is a line coverage created from 1:2,000,000-scale DLG coverages. The coverage contains lines representing roads in the map area. All DLG attributes have been stripped from the lines except ENTITY_LABEL, ROUTE_NUMBER1, ROUTE_NUMBER2, and ROUTE_NUMBER3 which contain the federal and state highway number designations.
Rr_lin is a line coverage created from 1:2,000,000-scale DLG coverages. The coverage contains lines representing railroads in the map area. It has no DLG attributes.
Grid_lin is a line coverage created to display projection lines in one degree increments. It has no attributes.