Field |
Description |
Main ID Information |
Metadata Updated 2007 |
Title |
Nicollet County Aggregate Resource Evaluation - Surficial Geology |
Filename |
Sg00xpy3 (ArcView Shapefile) |
Abstract |
This dataset consists of information about the geology, geological characteristics, and aggregate potential of 77 map units. The geology is divided into 4 fields that describe the sources, features, material, and surficial geology unit. The geological characteristics include probability, deposit size, thickness, overburden, texture, and quality. These characteristics were used to calculate the aggregate potential of the unit. |
Place Keywords |
Nicollet County, Minnesota |
Theme Keywords |
Surficial Geology, Geological Characteristics, Potential |
Time Period of Content |
Summer and Fall 1999 |
Parent Theme |
NA (FIELDOBS) |
Spatial Extent of the Data |
Nicollet County, Minnesota |
Contact Person |
Aggregate Resource Mapping
Program (Geologist or GIS Specialist) St. Paul, MN 55155-4045 |
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 of the different units. To help catagorize the geological characteristics and incorporate them into a model to help determine the geological potential of the deposit. |
Progress |
Complete |
Currentness Reference |
All data was gathered in the fall of 1999 and the spring of 2000 and compiled in the Summer and Fall of 2000. |
Maintenance Frequency |
None Planned |
Access Constraints |
NA |
Use Constraints |
NA |
Associated Data Sets |
Field Observations (FIELDOBS), Aggregate Resources of Nicollet County Minnesota |
Data Quality |
|
Attribute Accuracy |
The units were delineated by the interpretation of aerial photographs at a 1:40,000 scale. These interpretations were plotted on 1:24,000 USGS topographic maps. These delineations and unit descriptions were field checked and revised. This was a reconnasance scale study and was mapped at 1:50,000. |
Logical Consistency |
NA |
Completeness |
The units were delineated by aerial photograph interpretations. The potential of the deposit is based on geological factors and not economical factors. Generalizations were made, this is a reconnaissance scale study (1:50,000) |
Horizontal Positional Accuracy |
1:50000 |
Vertical Positional Accuracy |
NA |
Lineage |
The first step in determining the distribution of aggregate resources is to understand the surficial geology and the recent geological history of the area. The geological history basically tells us the story, or sequence of events, of when the aggregate and other sediments were deposited. By understanding this story we can determine where the aggregate was deposited, as well as some of the general characteristics about the material. This was accomplished for this study by completing an aerial photograph interpretation of the entire county and confirming these interpretations with approximately 900 water well logs and by observing approximately 950 field sites. Several other data sets and techniques were also used and are described below. These interpretations and observations were then compiled to form a sequence of events to tell the geologic story. Finally, the aggregate bearing landforms were delineated and categorized based on their geological characteristics. |
Source Scale Denominator |
1:50000 |
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 |
Raster only |
|
Cell Width |
NA |
Cell Height |
NA |
Spatial Data Organization |
|
Geographic Reference for Tabular Data |
The units are referenced as geological features (glacial drift, bedrock, and modern sediments). |
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 |
4541 kb |
Entities -- Attributes |
|
Entity-Attribute Overview |
Geological Features, Geological Characteristics, and Aggregate Potential. |
Entity-Attribute Detailed Citation |
See table below: Arcview specific fields include shape (i.e., feature type = polygon), area (given in square meters), perimeter (given in meters), filename_ (unique id for polygon, assigned by the software), filename_i or filename_id if filename is less than 8 characters (an id usually assigned during theme creation). |
Table Name |
Field Name |
Begin Column |
Definition |
Valid Values |
Descriptions |
SG00XPY3.dbf |
Map_unitno |
|
Number,3,0 |
Ex: 101-850. |
Unique identifier (Numbers have no significance). |
|
Descriptio |
|
Text, 58 |
Ex: Glaciofluvial Outwash, Major Terrace Deposit. |
A short, summarized description of the mapping units. |
|
Age |
|
Text, 20 |
Ex: Cretaceous, Holocene, Pleistocene, Ordovician, Cambrian, Precambrian, etc. |
Describes the age of the material encountered. |
|
Sg_plate3 |
|
Text, 75 |
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 |
|
Process |
|
Text, 20 |
Alluvial |
The geological process that deposited these features. Alluvial processes are modern stream processes. |
|
|
|
|
Bedrock |
Cambrian age formations such as the Jordan Sandstone or St. Lawrence Formations deposited by ancient seas advancing and retreating. |
|
|
|
|
Colluvial |
Material that was deposited as slope wash or slump along steep banks. |
|
|
|
|
Glacial |
Unsorted glacial material deposited in place. |
|
|
|
|
Glaciofluvial |
Glacial Sediments that have been sorted by meltwater. |
|
|
|
|
Lacustrine |
Modern Lake Processes. |
|
|
|
|
Man-made |
A man made holding pond/sediment pool. |
|
Feature |
|
Text, 20 |
Ex: Alluvial Fan, Alluvial Terrace, Bedrock, Colluvium, Drainage Pond, Esker, Floodplain, etc... |
The type of geological feature encountered at the surface (surficial geology) . Surficial Geology is defined as the geologic units encountered in the top 5 to 10 feet of the surface. |
|
Material |
|
Text, 28 |
Ex: Gneiss, Kaolin, Sand, Gravel, Clay, Limestone, Etc... |
The dominant type of material encountered in the surficial geologic unit. |
|
Probabilit |
|
Text, 15 |
Very High, High, Moderately High, Moderate, Moderately Low, Low, Very Low. |
The relative degree of certainty that aggregate exists within a unit. Based on air photo interpretations, field observations, CWI, drilling, presence of gravel pits and quarries, etc... Relative to each other ranging from very high to very low. |
|
Dep_size |
|
Text, 16 |
Very Large |
Size of the aggregate 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 |
|
Thickness |
|
Text, 5 |
Ex: 0-10, <10, >10, 20-50, >50 |
The assumed range of thickness of an aggregate deposit (in feet). |
|
Overburden |
|
Text, 5 |
Ex: 0-10, 0-3,<5, >20, 10-20, 20-50 |
The assumed range of overburden thickness of an aggregate deposit (in feet). |
|
Texture |
|
Text, 15 |
Very Good, Good, Moderately Good, Moderate, Moderately Poor, Poor, Very Poor. |
A relative scale of the textural quality of the aggregate 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. |
|
Quality |
|
Text, 15 |
Very Good, Good, Moderately Good, Moderate, Moderately Poor, Poor, Very Poor. |
A relative scale of the quality of the aggregate resources (soundness, durability, and mineral makeup). Determined from MN/DOT pit sheets. Very Good Quality Sand and Gravel deposits in Nicollet County are rare, even the best do not always meet MN/DOT specifications for concrete and asphalt. |
|
Pot_plate1 |
|
Text, 15 |
Bedrock |
Defines the Aggregate Potential as 3 units: the best aggregate deposits (those most desirable) and the less desirable deposits. The aggregate units that are either moderately or highly desirable for crushed stone potential. |
|
|
|
|
Sand and Gravel |
The aggregate units with either moderate or highly desirable sand and gravel deposits. |
|
|
|
|
Limited |
The units with less desirable aggregate deposits or limited deposits. |
|
Pot_Plate2 |
|
Text, 24 |
High sand and gravel |
These units with highly desirable sand and gravel deposits. Desirability is determined by the aggregate potential parameters (ap_xxxxx, as described above). High refers to highly desirable sand and gravel units. |
|
|
|
|
Moderate sand and gravel |
Moderately desirable sand and gravel units |
|
|
|
|
Low sand and gravel |
Less desirable sand and gravel units |
|
|
|
|
High bedrock |
Highly desirable bedrock units (Sioux Quartzite). |
|
|
|
|
Moderate bedrock |
Moderately desirable bedrock units (Sioux Quartzite, Granitic Gneisses, Limestones). |
|
|
|
|
Low bedrock |
Less desirable bedrock units (limestone). |
|
|
|
|
Limited |
Those units with little or no potential for aggregate. |
|
Pot_yorn |
|
Text, 9 |
Potential |
All aggregate resources (sand, gravel, and crushed stone) that have potential. Includes highly, moderately, and less desirable aggregate resources. |
|
|
|
|
Limited |
Those units with limited potential. No identified significant aggregate resources. |
|
Pot_4class |
|
Text, 8 |
High |
Aggregate Potential: All units that have highly desirable aggregate resources. |
|
|
|
|
Moderate |
All units that have moderately desirable aggregate resources. |
|
|
|
|
Low |
All units that have less desirable aggregate resources. |
|
|
|
|
Limited |
All units that have limited potential for aggregate resources. |
|
Aggr_min |
|
Number,3,0 |
Ex: 0,5,10,15,20,50 |
Describes the minimum thickness of the aggregate unit. |
|
Aggr_max |
|
Number,3,0 |
Ex: 0, 5, 10, 20, 30, 40, 50 |
Describes the maximum thickness of the aggregate unit. |
|
Over_min |
|
Number,3,0 |
Ex: 0, 10,20 |
Describes the minimum thickness of the overburden covering the aggregate. |
|
Over_max |
|
Number,3,0 |
Ex: 0, 3, 5, 10, 20, 30 |
Describes the minimum thickness of the overburden covering the aggregate. |