Table Name | Field Name | Begin Column | Definition | Valid Values | Descriptions
Millsgp.dbf | Sgpot_id |  | Number, 4 | e.g., 100-999 | Unique identifier for the field-mapping units.
| Sediment |  | Text, 50 | e.g., Alluvium; Bedrock Outcrop; Patchy Silt, Sand, Gravel over Till; Clay, Silt, and Sand; Sand and Gravel; see below text values and their descriptions for information that will help discern each description which may contain multiple of these values | General description of the dominant sediment material for each mapping unit.
|  |  |  | Alluvium | Sediment deposited by a river or stream. Contains sediment particles ranging from clay, silt, sand, and gravel.
|  |  |  | Bedrock Outcrop | Exposure of bedrock
|  |  |  | Clay | Clay is very fine-grained sediment that is less than.0.004 mm in size.
|  |  |  | Gravel | Rock fragments of specific particle size that is larger than 2 mm and less than 63 mm.
|  |  |  | Organics | Soil that contains decaying organic matter.
|  |  |  | Sand | Rock fragments that range in diameter from 0.0625 to 2 mm.
|  |  |  | Sand with Gravel | Sediment that contains a mixture of rocks in varying sizes ranging from 0.0625 to 64 mm. This description is given to sediment that contains less than 15% by volume gravel.
|  |  |  | Sand and Gravel | Sediment that contains a mixture of rocks in varying sizes ranging from 0.0625 to 64 mm. This description is given to sediment that contains greater than 15% by volume gravel.
|  |  |  | Silt | Rock fragments that have a diameter between 0.004 to 0.0625 mm.
|  |  |  | Till | A term used to describe the unsorted sediment deposited by glaciers- contains a mixture of clay, silt, sand, gravel and boulders.
| Sgpot_Desc |  | Text, 125 | e.g., Mostly till with isolated pockets of sand and gravel. | A summarized description of each mapping unit.
| Landform |  | Text, 50 | See Below | The geological landform associated with each mapping unit
|  |  |  | Alluvial Valley | Valley carved by flowing water like a river, stream or creek valley.
|  |  |  | Beach | A feature that forms along a shoreline that usually consists of sorted sands, gravels, and cobbles
|  |  |  | Collapsed Outwash Channel | An outwash channel is a stream carrying glacial meltwater that deposited sorted silts, sands, gravels, and cobbles. Collapse is a tern used to describe an uneven topography where the original sediment was deposited on top of ice or over buried ice. After deposition, the ice melted to form an uneven topographic expression.
|  |  |  | End Moraine | A glacial landform that forms at the very end, or terminus, of a glacier. The resulting landform is a ridge-like accumulation of till that can range from a distinct ridge to a large-scaled hummocky landform.
|  |  |  | Esker | A long, narrow, sinuous, steep-sided ridge composed of irregularly stratified sand and gravel. The sediments are ice contact features, meaning that the stream was flowing between ice walls or in an ice tunnel.
|  |  |  | Ground Moraine | Till covered areas with irregular topography forming gently rolling hills or plains. It is accumulated under glacial ice as transports and deposits sediment.
|  |  |  | Ice Contact Feature | A landform consisting of sediments that was initially contained or bound by glacial ice. Steep slopes characterize these landforms where ice once existed.
|  |  |  | Lake Plain | Characterized by a flat topography consisting of sands, silts, and clays formed by the impoundment of glacial meltwater forming a glacial lake.
|  |  |  | Lateral Moraine | A glacial landform that forms at the side of glacial ice resulting in a ridge-like accumulation of till.
|  |  |  | NA | Not applicable/available
|  |  |  | Outwash Channel | Stratified sediments, chiefly sand and gravel, removed or “washed out” from a glacier by meltwater streams and deposited in a channel or valley.
|  |  |  | Outwash Feature | A landform consisting of stratified sediments, chiefly sand and gravel, removed or “washed out” from a glacier by meltwater streams and deposited in front of or beyond the end moraine or the margin of an active glacier.
|  |  |  | Recessional Moraine | Consisting of mostly till as well as stratified sediments. A recessional moraine forms during brief standstills in a glaciers retreat.
|  |  |  | Stagnation Moraine | Stagnant moraines are formed by glacial ice that is no longer flowing, but instead, is melting and depositing sediment that includes flow tills, meltout tills, and stratified sands and gravels.
|  |  |  | Thrust Depression | A low spot in the topography resulting from glacial ice removing or thrusting the frozen sediment -usually paired with a corresponding thrusted hill.
|  |  |  | Thrust Hill | A hill created by the thrusting of frozen sediment- paired with a corresponding depression.
|  |  |  | Thrusted/End Moraine | This term is used to describe the Mille Lacs end moraine. Most of the topography of the moraine is due to thrusting of older sediment and capped by a variable thickness of Superior Lobe till.
| Potential |  | Text, 50 | See Below |
|  |  |  | Potential for Sand and Gravel Resources | Geologic units that are inferred to contain sand and gravel. These units exhibit the geologic characteristics that typically produce sand and gravel deposits. Existing gravel pit and MN/DOT aggregate sources lying within these units are considered identified or known resources. These resources include the classes High and Moderate potential for sand and gravel deposits.
|  |  |  | Limited Potential for Sand and Gravel Resources | Units that generally have little or no potential for significant aggregate resources. These units exhibit geologic characteristics that are typically not consistent with significant aggregate deposits. These units typically contain clay, silt, fine sand, unsorted sediments (till), or very thin layers of sand and gravel. These units may include aggregate deposits that are too small to map.
| Class |  | Text, 50 | See Below |
|  |  |  | High Potential for Sand and Gravel Resources | Glaciofluvial features, outwash plains, channels, and terraces as well as ice contact features like eskers, fans and kames (see Viewshed A and B). Deposits consist typically of sand and gravel. The probability1 that a potential sand and gravel deposit exists within any mapping unit is moderately high to very high. Thickness of the deposits ranges from 15 to 40+ feet with less than 15 feet of overburden. These deposits are moderately large to very large in areal extent2 and the textural characteristicsł are moderately good to very good. The quality4 is typically moderately high to very high relative to other deposits within Mille Lacs County.
|  |  |  | Moderate Potential for Sand and Gravel Resources | Glaciofluvial features, outwash plains, channels, and terraces as well as ice contact features like eskers, fans and kames. Deposits consist typically of sand and gravel. The probability that a potential sand and gravel deposit exists within this unit is moderate to very high. Deposit thickness ranges from 10 to 40+ feet with less than 20 feet of overburden. These deposits are moderate to large in areal extent and the textural characteristics are moderate to very good. The quality is typically moderate to high.
|  |  |  | Low Potential for Sand and Gravel Resources | Glaciofluvial features, outwash plains, channels, and terraces; ice contact features like eskers, fans and kames; and alluvial channels. Deposits consist of sand, sand with gravel, or silty sand and gravel. The probability that a potential deposit exists within this unit is low to moderately low. Thickness of the deposits ranges from 5 to 40+ feet with overburden thickness ranging from 0 to 50+ feet. These deposits are small to moderate in areal extent and the textural characteristics are moderately poor to good. The quality ranges from low to high.
|  |  |  | Limited Potential for Sand and Gravel Resources | Units that include glacial features such as scoured glaciofluvial channels, ground moraines, end moraines, and small alluvial features such as flood plains and streams. The deposits of this unit contain all or one of the following: clay with boulders, silt, sand, and/or gravel. The probability that a significant sand and gravel deposit exists within this unit is very low to moderately low. The thickness of these deposits is typically less than 10 feet but can range from 0 to 30+ feet with overburden thickness ranging from 0 to100 feet. The sand and gravel deposits occurring in this unit are very small to moderately small in areal extent. The textural characteristics are poor to moderately good with the quality ranging from very low to moderately low.
| Probablty |  | 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.
| Size |  | Text, 20 | Very large, Large, Moderately Large, Moderate, Moderately Small, Small, Very Small | The relative size of the sand and gravel deposit
| Acreage |  | Text, 8 | See Below | The size of the deposit in acres.
|  |  |  | 50+ | Very Large
|  |  |  | 30-50 | Large
|  |  |  | 10-30 | Moderate
|  |  |  | 5-10 | Small
|  |  |  | <5 | Very Small
| Texture |  | Text, 20 | Very Good, Good, Moderately Good, Moderately Good, Moderate, Moderately Poor, Moderately Poor, 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.
| Quality |  | Text, 20 | Very High, High, Moderately High, Moderately High, Moderate, Moderately Low, Low, Very Low | A relative scale of the quality of the sand and gravel (soundness, durability, and mineral makeup). Determined from MN/DOT pit sheets.
| Dom_litho |  | Text, 30 | See Below | Glacial Lobe Source
|  |  |  | Des Moines Lobe Sediments | A glacial lobe that flowed from the northwest, down the Minnesota River valley to a glacial maximum in Des Moines, Iowa. A sublobe flowed north from Mankato into the Twin Cities basin. It is this sublobe that deposited sediment in the southern portion of Mille Lacs County. A tan, silty loam with the indicator lithologies of shale and limestones characterizes the till. Sediment from this lobe tends to produce aggregate with lower quality due to the water absorption of the shale and higher percentages of soft limestones and iron oxides.
|  |  |  | Des Moines/Superior Lobe Sediments | Des Moines Lobe sediment (see description above) stratigraphically above Superior Lobe sediment (see description below)
|  |  |  | Rainy Lobe Sediments | Rainy Lobe is a northeastern sourced glacier flowing along the highlands of eastern Minnesota to the southwest. Rainy Lobe sediments tend to contain high percentage of granites and granitic rock types. Aggregate with Rainy Lobe rock lithologies generally are of high quality and durability.
|  |  |  | Superior Lobe Sediments | Superior Lobe is a northeastern sourced glacier flowing from the Lake Superior basin to the southwest. Superior Lobe sediments tend to contain rhyolites, basalts, and other Duluth Complex rock types. Aggregate with Superior Lobe rock lithologies generally are of high quality and durability.
|  |  |  | Superior/Rainy Lobe Sediments | Superior Lobe sediments stratigraphically above Rainy Lobe sediments.
| Thickness |  | Text, 15 | 5-15, 10-30, 20-100+ | Gives range of minimum and maximum thickness for sand and gravel deposit
| Thick_mod |  | Text, 1 | + | The thickness modifier indicates that the thickness of the unit exceeds the value listed in the Thick_max field.
| Thick_min |  | Integer, 4 | 0, 5, 10, 15, 20, 25, 30 | Describes the minimum thickness of the sand and gravel unit.
| Thick_max |  | Integer, 4 | 5, 10, 15, 20, 25, 30, 40, 50, 75 | Describes the maximum thickness of the sand and gravel unit.
| Overburden |  | Text, 15 | 0-100+, 0-5, 10-50 | Gives range of minimum and maximum thickness for overburden
| Ob_mod |  | Text, 1 | + | The overburden modifier indicates that the thickness of the overburden exceeds the values listed in the Ob_max field.
| Ob_min |  | Integer, 4 | 0, 3, 10, 20 | Describes the minimum thickness of the overburden covering the sand and gravel.
| Ob_max |  | Integer, 4 | 1, 3, 5, 10, 15, 20, 30, 40, 50 | Describes the maximum thickness of the overburden covering the sand and gravel.
| Buried_dep |  | Text, 3 | Yes or No | ‘Yes’ indicates that the deposit/mapping unit is buried by significant overburden (30-40 ft.)
| Mndot_data |  | Text, 3 | Yes or No | ‘Yes’ indicates that the deposit/mapping unit has a MN DOT ASIS data sourced point (see millpits.shp, field – SOURCE, value - ‘ASIS’).
| Map_label |  | Text, 2 | See Below | A cartographic map label for the sand and gravel potential classifications
|  |  |  | Hp | High Potential for Sand and Gravel Resources
|  |  |  | Mp | Moderate Potential for Sand and Gravel Resources
|  |  |  | Lp | Low Potential for Sand and Gravel Resources
|  |  |  | Lt | Limited Potential for Sand and Gravel Resources