AGGREGATE POTENTIAL – SAND AND GRAVEL MAPPING UNITS

DODGE COUNTY, MINNESOTA

Field | Description
Main ID Information | Metadata Updated 2007
Title | Dodge County Aggregate Resource Evaluation
Filename | Agg02py3 (ArcView Shapefile)
Abstract | This dataset consists of information about the geology, geological characteristics, and sand and gravel potential of 69 map units. Five fields (attributes) relate to the surficial geology of the map unit. Eleven fields (attributes) relate to the sand and gravel characteristics, including probability, quality, texture, overburden thickness, and deposit size, of the map unit. These characteristics were used to calculate the aggregate potential of the map unit for sand and gravel.
Place Keywords | Dodge County, Minnesota
Theme Keywords | Surficial Geology, Geological Characteristics, Aggregate Potential, Sand, Gravel
Time Period of Content | Fall 2001 – Spring 2002
Parent Theme |
Spatial Extent of the Data | Dodge County, Minnesota
Contact Person | Aggregate Resources Mapping Program
Contact Person Organization/Division | Department of Natural Resources, Division of Lands and Minerals
Contact Person Position | Geologist or GIS Specialist
Contact Address | 500 Lafayette Road, Box 45
Contact City | St. Paul
Contact Zip Code | 55155-4045
Contact Voice Phone | 651-259-5959
Contact Fax Phone | 651-296-5939
Additional ID Information |
Originator | Department of Natural Resources, Division of Lands and Minerals, Mineral Potential Section
Purpose | To summarize the geological characteristics, surficial geology, and aggregate potential (sand, gravel) of the different units. To help categorize the geological characteristics and incorporate them into a model to help determine the aggregate potential of the deposit.
Progress | Complete
Currentness Reference | All data was gathered in summer and fall of 2001 and compiled in the fall of 2001 through the spring of 2002.
Maintenance Frequency | None Planned
Access Constraints | NA
Use Constraints | NA
Associated Data Sets | County Aggregate Mapping Program datasets for Dodge County, including data on sand and gravel potential, crushed stone potential, field observations, rock piles, and test pit quality data.
Data Quality |
Attribute Accuracy |
Logical Consistency | NA
Completeness | The sand and gravel and surficial geology units were delineated by the interpretation of aerial photographs at a 1:40000 scale. These interpretations were plotted on 1:24000 USGS topographic maps. These delineations and unit descriptions were field checked and revised. The final coverage was digitized onscreen using Arcview with USGS DOQs (at a scale of 1:12000) and USGS DRGs (at a scale of 1:24000) as the spatially registered backdrops. This was a reconnaissance-scale survey and was mapped at 1:50000.
Horizontal Positional Accuracy | 1:50,000 for sand and gravel.
Vertical Positional Accuracy | NA
Lineage | Color infrared and black-and-white aerial photographs were used to delineate geological landforms and aggregate resources. Stereoscopic pairs of color infrared aerial photographs (NAPP, 9"x9" at 1:40,000 scale, April 1991 and 1992) were used along with reconnaissance-level, high-altitude, black-and-white photographs (1:80,000 scale). Aerial photographs (DOQs) were also available digitally and used within ARCVIEW (1:12,000 scale). Aerial photographic interpretation was completed with a glacial mapping technique known as the landsystems approach. This technique relies on the principle that depositional glacial landforms are composed of a predictable range of sediments, some consisting of sorted sand and gravel and others consisting of silts, clays, or unsorted materials. In addition to the landsystems approach, several other general characteristics helped determine the nature of the material, such as tonal contrasts, texture, context, shape, size, trend, association, and patterns. These characteristics can help determine the properties of the surface material (e.g., certain vegetation grows on well drained soils such as sand and gravel, which on an aerial photograph has a distinctive texture, tone, pattern, etc.). The landform recognition approach (part of the landsystems approach) was also used when interpreting the topography within Dodge County; glacial landforms have distinct and unique shapes and patterns that can be observed in their topographic expression. Topographic maps (USGS 1:24,000), digital elevation models, and shaded relief maps were all used to help delineate these sand and gravel bearing features. The topographic expression of a feature can also be observed by looking at the distribution of lakes and wetlands. For example, a string of lakes and/or wetlands may be the signature of a glacial outwash channel or collapsed channel, which may host sand or gravel deposits. Several aggregate bearing features were located using this technique (outwash channels, collapsed channels, glaciofluvial fans, eskers, and terraces).
Source Scale Denominator | 1:50,000
Spatial Reference |
Horizontal Coordinate Scheme | UTM
Ellipsoid | GRS80
Horizontal Datum | NAD83
Horizontal Units | Meters
Distance Resolution | NA
Altitude Datum | NA
Altitude Units | NA
Depth Datum | NA
Depth Units | NA
UTM Zone Number | 15 Extended
Raster only |
Cell Width | NA
Cell Height | NA
Spatial Data Organization |
Geographic Reference for Tabular Data |
Native Dataset Environment | ArcView 3.1/ArcInfo 8.0.2
Vendor Specific Object Type | NA
Tiling Scheme | County
Spatial Object Type | Vector-polygon
Transfer Size | 2080 kb
Entities -- Attributes |
Entity-Attribute Overview | The polygons were delineated to represent geological features, geological characteristics, and aggregate potential for sand and gravel.
Entity-Attribute Detailed Citation | ArcView specific fields include shape (i.e., feature type = polygon), area (given in square meters), perimeter (given in meters), Agg02ne3_ (counter field - assigned by the software), and Agg02ne3_id (an id usually assigned during theme creation). The aggregate potential attributes for the polygons are described in the table below.

Table Name | Field Name | Begin Column | Definition | Valid Values | Descriptions
Agg02py3.dbf | Sg_mapu |  | Number,4,0 | Ex: 101-240. | Unique identifier for mapping units
| Surfdesc |  | Text, 60 | Ex: Glaciofluvial Outwash, Outwash Modified Till. | A short, summarized description of the surficial geologic mapping units.
| Sgeo_age |  | Text, 30 | Ex: Holocene, Precambrian, Quaternary, etc. | Describes the age of the material encountered at the surface.
| Surfgeo_pl3 |  | Text, 50 | Ex: Alluvial Fan Sediments, Alluvial Terrace Sediments, Glaciofluvial Fan Sediments, etc. | Describes the surficial geologic unit. It may be a bedrock material, a glacial sediment, or a modern Holocene sediment
| Sgeo_proc |  | Text, 30 | Alluvial | The geological process that deposited these features. Alluvial processes are modern stream processes.
|  |  |  | Alluvial over Glaciofluvial | Modern stream processes overlying glaciofluvial (glacial stream) processes
|  |  |  | Bedrock | Ordovician age limestones, shales, and sandstones that were deposited by an ancient sea millions of years ago.
|  |  |  | Colluvium | Material that was deposited as slope wash or slump along steep banks.
|  |  |  | Eolian | Material that was deposited by wind.
|  |  |  | Eeolian over Glaciofluvial | Material that was deposited by wind overlying glaciofluvial (glacial stream) processes
|  |  |  | Eroded Glaciofluvial | Glacial sediments that were originally sorted and deposited by meltwater and was has since been subject to erosion
|  |  |  | Erosional Glacial | Unsorted glacial material that was subject to erosion.
|  |  |  | Glacial | Unsorted glacial material deposited in place.
|  |  |  | Glaciofluvial | Glacial sediments that have been sorted by meltwater.
|  |  |  | Laucustrrine | Sediments deposited at the bottom of an ancient glacial lake.
| Sgeo_feat |  | Text, 35 | Ex: Alluvial Fan, Alluvial Terrace, Bedrock Outcrop, Beach, Kame, Esker, Flood Plain, etc... | The type of geological feature encountered at the surface (surficial geology). Surficial Geology is defined as the geologic units encountered within the top 5 to 10 feet of the surface.
| Sgeo_mat |  | Text, 35 | Ex: Des Moines Till, Granite, Sand, Sand and Gravel, Silt and Clay, etc… | The dominant type of material encountered in the surficial geologic unit.
| Sg_prob |  | Text, 20 | Very High, High, Moderately High, Moderate, Moderately Low, Low, Very Low. | The relative degree of certainty that sand and gravel exists within a unit. Based on air photo interpretations, field observations, CWI, drilling, presence of gravel pits and quarries, etc. Each unit is relative to the other units and range from very high to very low.
| Sg_depsize |  | Text, 20 | Very Large | Size of the sand and gravel deposit (areal extent). Ex: number of acres. A very large deposit would be considered > 50 acres.
|  |  |  | Large | 40-50 acres
|  |  |  | Moderately Large | 30-40 acres
|  |  |  | Moderate | 20-30 acres
|  |  |  | Moderately Small | 10-20 acres
|  |  |  | Small | 5-10 acres
|  |  |  | Very Small | < 10 acres
| Sg_thick |  | Text, 10 | Ex: 0-10, <10, >10, 20-50, >50 | The assumed range of thickness of the sand and gravel deposit (in feet).
| Sg_ovrbrdn |  | Text, 10 | Ex: 0-10, 0-3,<5, >20, 10-20, 20-50 | The assumed range of overburden thickness of a sand and gravel deposit (in feet).
| Sg_texture |  | Text, 20 | Very Good, Good, Moderately Good, Moderate, Moderately Poor, Poor, Very Poor. | A relative scale of the textural quality of the sand and gravel resource (sieve analysis). The coarser the material the higher the rating. Fine sand material would have a poorer rating. See MN/DOT Pit sheets for more detail.
| Sg_quality |  | Text, 20 | Very Good, Good, Moderately Good, Moderate, Moderately Poor, Poor, Very Poor. | A relative scale of the quality of the sand and gravel (soundness, durability, and mineral makeup). Determined from MN/DOT pit sheets.
| Sg_pot_pl1 |  | Text, 15 | Limited, Sand and Gravel. | Sand and Gravel Potential that is depicted on plate 1 (Significant Aggregate Resources). Sand and Gravel refers to those units that have a high to moderate potential of containing significant sand and gravel deposits. Desirability is determined by the sand and gravel potential attributes (Sg_xxxxx, as described above).
| Sg_pot_pl2 |  | Text, 15 | High, Moderate, Low, Limited. | Sand and Gravel Potential that is depicted on plate 2 (Aggregate Resources). High, Moderate, and Low refer to the relative potential of the Sand and Gravel units. Desirability is determined by the sand and gravel potential attributes (Sg_xxxxx, as described above). Limited refers to those units that do not contain sand and gravel or where the deposits are insignificant.
| SGpot_plate1 |  | Text, 15 | Sand and Gravel | Aggregate Potential (Sand, Gravel, and Crushed Stone) that is depicted on Plate 1 (Significant Aggregate Resources). Sand and Gravel refers to those units with moderate or high potential of containing significant sand and gravel resources.
|  |  |  | Bedrock | Those units with moderate or high potential of containing significant crushed stone resources.
|  |  |  | Sand and Gravel over Bedrock. | Those units with moderate or high potential of containing significant sand and gravel resources overlying areas with moderate or high potential of containing significant crushed stone resources.
|  |  |  | Limited | Those areas containing low potential sand, gravel, and crushed stone resources, as well as area with limited potential.
| Sg_min |  | Number,3,0 | Ex: 0,5,10,15,20,50 | Describes the minimum thickness of the sand and gravel unit.
| Sg_max |  | Number,3,0 | Ex: 0, 5, 10, 20, 30, 40, 50 | Describes the maximum thickness of the sand and gravel unit.
| Sgover_min |  | Number,3,0 | Ex: 0, 10,20 | Describes the minimum thickness of the overburden covering the sand and gravel.
| Sgover_max |  | Number,3,0 | Ex: 0, 3, 5, 10, 20, 30 | Describes the maximum thickness of the overburden covering the sand and gravel.