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.