AGGREGATE RESOURCE POTENTIAL

EASTERN CLAY COUNTY, MINNESOTA

Field	Description
Main ID Information	Metadata Updated 2007
Title	Aggregate Resource Potential of Eastern Clay County, Minnesota. These layers are part of Minnesota Department of Natural Resources, Minerals Division, Report 306, from 1997.
Filename	Shapefiles: agg97py3, agg97ln3, sym97ln3
Abstract	This dataset consists of information about aggregate potential based on geological factors. This work is authorized by Minnesota Statute 84.94.
Place Keywords	Clay County, Minnesota; eastern 18 townships of county (Barnesville, Cromwell, Eglon, Elkton, Felton, Flowing, Goose Prairie, Hagen, Hawley, Highland Grove, Humboldt, Keene, Parke, Riverton, Skree, Spring Prairie, Tansem, Ulen)
Theme Keywords	Aggregate potential, geological characteristics
Time Period of Content	1991-1995
Parent Theme
Spatial Extent of the Data	Eastern 18 townships of Clay County, Minnesota
Contact Person	Aggregate Resources Mapping Program
Contact Person Organization/Division	Minnesota 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, MN
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 aggregate resource potential of the various mapping units.
Progress	Complete
Currentness Reference	NAPP aerial photographs from 1991-1992, air photo interpretation 1994-1995, field work 1995.
Maintenance Frequency	None planned
Access Constraints	NA
Use Constraints	These layers do not contain water or wetlands since there are layers available at different levels of accuracy and scale. To most effectively use this dataset, add wetlands and water that are at a scale of 1:24000, if possible. As of 4/2001, it is possible to download both of these layers from http://deli.dnr.state.mn.us. To add 1:24000 layers, look under hydrography, DNR 24K Lakes and National Wetlands Inventory polygons.
Associated Data Sets	shapefiles: gp97apt3 - gravel pits, gp97bpt3 - MN DOT test pit data, glb97pt3 - MN DOT test pit data - label points Access 97 database: dotpit97.mdb
Data Quality
Attribute Accuracy	The mapping 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 coverage was created by digitizing the delineations drawn on the 1:24,000 topographic maps.
Logical Consistency	NA
Completeness	The units were delineated by aerial photograph interpretations. The potential of deposits is based on geologic factors, not economic factors. Generalizations were made, resulting in a product that should be considered reconnaissance level and accurate to a scale of 1:50,000.
Horizontal Positional Accuracy	1:50,000
Vertical Positional Accuracy	NA
Lineage	These shapefiles are part of Minnesota Department of Natural Resources, Minerals Division, Report 306, Aggregate Resource Potential of eastern Clay County, 1997, by JD Lehr and is part of an ongoing statewide program to provide aggregate resource information to the public. It is based on mapping the Quaternary (i.e., surficial) geology of a county. Once this is done, aggregate potential is determined by examining geologic factors and assigning aggregate potential values to these geologic features. Aggregate potential for Clay County was originally derived from Quaternary geology features. Lakes were not included as an aggregate resource potential mapping unit, since there are many different versions of lakes, available in digital format, for Clay County. The user can therefore lay their choice of water layers, as well as other types of data, over the aggregate resource potential layer. (Note: for the published map of Clay County, the water layer used for lakes is from MNDOT's Base Map, 1996.) A variety of features on a landscape may affect its value as an aggregate source besides "raw" or "native" potential interpreted from surficial geology, such as the presence of water. Users are therefore advised to consider other features, such as water bodies and wetlands, when using the aggregate resource potential layer in any decision-making capacity. Gravel pit features mapped in this layer represent pits large enough to be recognized as area units on aerial photography (1:40,000 scale) from 1991-1992. The description "gravel pit" covers both pits currently being mined, as well as areas currently inactive. This distinction between currently active and inactive pits is made explicit in the data attributes AGGPOT, DEP_TYPE, GENET_UNIT, and POTENTIAL. This condition is subject to frequent change as pits open or close in response to aggregate supply and market conditions, making such a distinction of limited value. This information should be used with caution. Other types of gravel pits (those mapped as points rather than polygons [areal features]) can be found in the gp97apt3 shapefile. The user should recognize that this layer represents a "snapshot in time" of an evolving gravel pit picture in Clay County. Source NAPP air photos are generally dated 1991-1992, and should not be deemed representative of conditions either before or since. The user should also recognize that the geographic capture and display of geologic features is by nature problematic, for two primary reasons. First, such features extend underground, beyond the view of the interpreter. Second, geologic features tend to occur as zones of transition better represented as areas, rather than as sudden feature changes represented by lines. These factors should be considered when displaying and using these data.
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	NA
Native Dataset Environment	ArcView 3.1 / Arc/INFO 7.2.1
Vendor Specific Object Type	NA
Tiling Scheme	County/township
Spatial Object Type	Vector-polygon
Transfer Size
Entities -- Attributes
Entity-Attribute Overview	Aggregate resource potential units, geological factors
Entity-Attribute Detailed Citation	The basic relationships among the attributes is as follows (the complete table is listed below): Aggpot Dep_type Genet_unit Potential 219 B-1 BEACH RIDGE - MAJOR HIGH 119 B-2 BEACH RIDGE - MINOR MODERATE 118 B-3 BEACH - NO RIDGE SLIGHT 124 I-1 Di MODERATE 126 I-2 Dim SLIGHT 222 O-1 Do - "HIGH" HIGH 122 O-2 Do - "MODERATE" SLIGHT 223 O-3 Doc - "HIGH" HIGH 123 O-4 Doc - "MODERATE" HIGH 250 So Wom HIGH 190 GPA Gravel Pit-Active GRAVEL 191 GPI Gravel Pit-Inactive GRAVEL 100 LP Limited Potential LIMITED 101 NM Not Mapped NOTMAP The relationship between Dep_type and aggregate resource potential is as follows: HIGH POTENTIAL FOR AGGREGATE DEPOSITS TYPE B-1: Sand and gravel deposited in near-shore environments of Lake Agassiz. Forms prominent beach ridges. Aggregate deposits are typically thin (10 to 20 feet thick) and narrow, but generally have very little overburden. Gravel percentage is variable, and is generally dominated by fine gravel (#10 mesh to #4 mesh). Percentage of deleterious material, chiefly shale, is generally low. TYPE O-1: Sand and gravel deposited by glacial meltwater streams confined to a valley. Aggregate deposits in this unit are moderately thick. These deposits generally have very little overburden. Gravel percentage is fairly high, with a mixture of coarse and fine gravel. Percentage of deleterious material, chiefly shale, but including iron oxides, is moderately high. This unit represents part of the outwash valley train in the Hawley area where gravel mining has occurred and subsurface data indicate potential for further development. TYPE O-3 AND O-4: Sand and gravel deposited by glacial meltwater streams flowing upon stagnant ice. These two units form a collapsed outwash plain in the southeastern part of the county. Aggregate deposits have variable thickness, but are locally quite thick. Overburden thickness is also variable, but is generally minimal. Percent gravel is variable, but is locally quite high, with some areas containing appreciable quantities of coarse gravel. Percentage of deleterious material, chiefly shale, is moderately high. Unit O-3 is differentiated from unit O-4 by a higher density of gravel pits and by subsurface data indicating potential for further development. Aggregate deposits that may occur in unit O-4 will be very similar to Type O-3 deposits, but the probability of finding a deposit in these areas is inferred to be lower. TYPE SO: Sand and gravel deposited by subglacial meltwater streams where they entered a glacial lake that existed in the Red River Valley prior to Lake Agassiz. These deposits are not expressed as depositional landforms, but occur where the younger sediment has been removed by either stream erosion, or by wave erosion in Lake Agassiz. Aggregate deposits of this type are locally very thick (75 to 100 feet), but may be moderately thick, or absent in places. Overburden thickness is highly variable, ranging from minimal to excessive (greater that 50 feet). Gravel percentage is also highly variable, ranging from high percentage of coarse gravel to entirely sand. Percentage of deleterious material (shale and iron oxides) is generally very low. Potential for these types of deposits is inferred to be somewhat higher in proximity to the erosional features mapped within this unit. This type of deposit represents the highest quality aggregate resource present in the entire region. MODERATE POTENTIAL FOR AGGREGATE DEPOSITS TYPE B-2: Sand and gravel deposited in near-shore environments of Lake Agassiz. This unit represents minor beach ridges and, in some cases, off-shore bars composed entirely of sand. Examples of this type of deposit are not common, therefore, supporting data are not abundant. Aggregate deposits are inferred to be rather thin, but generally with minimal overburden. Low percentages of gravel will limit these deposits to certain uses. Percentage of deleterious material is inferred to be low. TYPE I-1: Sand and gravel deposited by glacial meltwater streams in contact with glacial ice, with some resedimentation by gravity flow processes. This unit occurs as eskers and irregular-shaped hummocks. Aggregate deposits of this type are variable in thickness, but generally of limited lateral extent, with a variable thickness of overburden. Percentage gravel is variable, but locally may be quite high, while in some areas the deposits may be entirely sand. Data on percent deleterious material is lacking, however the quality of these deposits is probably similar to type O deposits. SLIGHT POTENTIAL FOR AGGREGATE RESOURCES TYPE B-3: Chiefly sand, with local concentrations of sand and gravel, deposited in near-shore environments of Lake Agassiz. This unit consists of that portion of the shoreline area of Lake Agassiz that is outside the other mapping units (beach ridges for example). These deposits are generally thin. Deposits within this unit generally have little overburden. Percentage of gravel is quite variable, but is generally low to moderate. The gravel fraction may be predominantly fine gravel. Percentage deleterious material is generally low, as in other Type B deposits. Occurring within this unit in the vicinity of Muskoda are meltwater stream deposits similar to Type O-1, which are buried by till and beach-deposited sand and gravel. This unit has potential for other types of buried deposits, especially in the vicinity of shoreline erosional features. TYPE O-2: Chiefly sand deposited by glacial meltwater streams confined to a valley. This unit occurs in the glacial drainage channels east and south of Hawley. The aggregate potential of this unit will be limited by low percentage of gravel. Gravel-rich zones may occur beneath sand overburden. The percentage of deleterious material in this type of deposit is probably similar to other type O deposits, in other words, with moderate amounts of shale. TYPE I-2: Sand and gravel deposited by glacial meltwater streams in contact with glacial ice, with some resedimentation by gravity flow processes. Aggregate deposits of this type are variable in thickness and lateral extent. This type of deposit was subsequently buried by later glacial advances and therefore has a variable, but generally pervasive thickness of overburden. Percentage gravel is variable, but locally may be quite high, while in some areas the deposits may be entirely sand. Percent deleterious material is quite variable, but is generally moderate. LIMITED POTENTIAL FOR AGGREGATE RESOURCES TYPE LP: Geological units that generally have little or no potential for aggregate resources. In places, includes aggregate deposits either too small or extremely difficult to map. Composed primarily of glacial till and lacustrine silt.

Table Name	Field Name	Begin Column	Definition	Valid Values	Descriptions
agg97py3 shapefile					Aggregate potential and Quaternary geology polygons
	aggpot		Number,3,0	219,119,118,222,122,223,123,124,126,250,190,191,100,101	Aggregate potential deposit type, given as a number
	pittype		Number,2,0	0,90,91	90=active gravel pit, 91=inactive gravel pit, 0=not a gravel pit
	dep_type		Text,3	B-1,B-2,B-3, O-1,O-2,O-3,O-4, I-1,I-2, SO, GPA,GPI, LP,NM	Aggregate potential deposit type, given as a character string (presented in the same order as above, for aggpot).
	dep_source		Text,30	i.e., Lake Agassiz deposits, Des Moines lobe deposits, Wadena lobe deposits	The source of the depositional material. No source is given for the following genet_unit classes: Gravel pit - active, Gravel pit - inactive, Limited potential, Not mapped.
	genet_unit		Text,20	Beach ridge - major, Beach ridge - minor, Beach - no ridge, Do-"high", Do-"moderate", Doc-"high", Doc-"moderate", Di, Dim, Wom, Gravel pit-active, Gravel pit-inactive, Limited potential, Not mapped	Surficial (i.e., Quaternary) geology unit, further subdivided by moderate/high and by major/minor for those units with aggregate resource potential. Refer to genu_desc and genu_desc2 for additional explanations of these units. (These units presented in the same order as above, for aggpot).
	genu_desc		Text,80	Lake Agassiz beach ridge, major; Lake Agassiz beach ridge, minor; Lake Agassiz beach sediment, no apparent ridge; Northwestern source (Des Moines lobe) outwash; Northwestern source (Des Moines lobe) outwash; Northwestern source (Des Moines lobe) collapsed outwash; Northwestern source (Des Moines lobe) collapsed outwash; Northwestern source (Des Moines lobe) ice-contact stratified deposit; Buried northwestern source (Des Moines lobe) ice-contact stratified deposit; Buried northeastern source (Wadena lobe) subaqueous outwash.	A more complete description of the genet_unit, including the type of material and the source of the material. (These units presented in the same order as above, for aggpot).
	genu_desc2		Text,50	Beach ridge - major; Beach ridge - minor; Beach - no ridge; Des Moines lobe outwash; Des Moines lobe outwash; Des Moines lobe collapsed outwash; Des Moines lobe collapsed outwash; Des Moines lobe ice-contact deposit; Des Moines lobe ice-contact deposit, mantled; Wadena lobe outwash, mantled.	A secondary description of the genet_unit. (These units presented in the same order as above, for aggpot).
	potential		Text,8	i.e., High, Moderate, Slight, Limited, Gravel, Notmap	Aggregate resource potential rating
	shale_rank		Number,1,0	0,1,2,3	Ranking based on the percentage of shale, where the higher the number, the lower the amount of shale (and the better for aggregate resource potential).
	grav_rank		Number,1,0	0,1,2,3	Ranking based on the percentage of gravel, where the higher the number, the greater the amount of gravel.
	depsz_rank		Number,1,0	0,1,2,3	Ranking based on the size of the deposit, where the higher the number, the larger the potential size of the deposit.
	ovrb_rank		Number,1,0	0,1,2,3	Ranking based on the thickness of the overburden, where the higher the number the thinner the amount of overburden.
	prob_rank		Number,1,0	0,1,2,3	Ranking based on the probability of finding a deposit in the dep_type, where the higher the number the greater the probability of a deposit.
	cum_rank		Number,2,0	0,6,7,9,11,12	Cumulative ranking, based on adding the values in shale_rank, grav_rank, depsz_rank, ovrb_rank, and prob_rank, where the higher the number the higher the aggregate resource potential.
agg97ln3 shapefile					Quaternary geology polygon boundaries
	map_unit		Number,3,0	2,3,4,5, 11,12,52, 58,59, 60,62,65,69, 70,79, 99, 100,101	Type of line, given as a number.
	mu_desc		Text,50	County boundary; West boundary of mapped area; Township boundary on the west side; Gravel pit outline; Channel scarp; Channel scarp and geologic contact; Channel scarp and gravel pit outline; Wave-cut scarp and geologic contact; Wave-cut scarp and gravel pit boundary; Geologic contact; Geologic contact and gravel pit outline; Pseudo-contact through gravel pit; Geologic contact and lake boundary; Geologic contact - inferred, gradational; Geologic contact - inferred, and lake boundary; Water boundary; Aggregate potential boundary; 200 ft buffer of linear beach ridge feature.	Type of line, given as a text description (These units presented in the same order as above, for map_unit).
sym97ln3 - associated geology line shapefile					Geologic landforms, stored as lines
	origid		Number,3,0	11,12*,13,14*,15,17, 54**,55,58*,59** where * indicates that it is also in agg97ln3 because it is also a geologic contact, and ** indicates that it is also in agg97ln3 because it is also a gravel pit outline	Type of line, as originally mapped. Units 11 and 12 - fluvial channel scarp - right bank; 13 and 14 - fluvial channel scarp - left bank; 15 - fluvial channel scarp, approximately located, right bank; 17 - fluvial channel scarp, approximately located, left bank; 54 - fluvial channel scarp. Unit 55 -s wave-cut scarp; 56 - wave-cut scarp, approximately located; 58 and 59 - wave-cut scarp.
	mapid		Number,3,0	11,13,55	Type of line, as drawn on the project maps.
	map_desc		Text,50	11 - Fluvial channel scarp (for map symbol, coded as 11 for direction of line) 13 - Fluvial channel scarp (for map symbol, coded as 13 for direction of line)	An area that is/has been eroded by stream flow, often exposing areas with aggregate potential.
				55 - Wave-cut scarp	An area that was affected by wave action of Glacial Lake Agassiz, exposing areas of aggregate potential.