pot_redwoodField Name | Valid Values | Definition | Definition Source |
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SGPOT_ID | - | Unique identifier for the field- mapping units. | Esri |
Sediment | enumerated | General description of the dominant sediment material for each mapping unit. Multiple values may be used in descriptions. | |
| Clay | Clay is very fine-grained sediment that is less than 0.004 mm in size. | |
| Silt | Rock fragments that have a diameter between 0.004 to 0.0625 mm. | |
| Sand | Rock fragments that range in diameter from 0.0625 to 2 mm. | |
| Sand minor 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 between 5-15% by volume gravel. | |
| 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 between 15-35% 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 between 35-50% by volume gravel. | |
| Gravel | Rock fragments of specific particle size that is larger than 2 mm and less than 63 mm. | |
| Boulder | Rocks with a diameter >10 inches. | |
| Organics | Soil that contains decaying organic matter. | |
| Till | A term used to describe the unsorted sediment deposited by glaciers- contains a mixture of clay, silt, sand, gravel, cobbles and boulders. | |
| Cobbles | Rocks with a diameter between 3-10 inches. | |
| Organics | Soil that contains decaying organic matter. | |
| Fine Sand | Rocks and minerals that range in diameter of 0.0625 to 0.25 mm. | |
| Granite | A felsic igneous rock that has medium to coarse crystalline texture. Includes granite, quartz monzonite, and granodiorite based on Minnesota Geological Survey bedrock descriptions. Referred to as “Sacred Heart Granite”. | |
| Granite/Gneiss | A coarse-grained crystalline and metamorphic rock. Includes foliated, biotite tonalitic to granodioritic gneiss based on Minnesota Geological Survey bedrock descriptions. Referred to as “Morton Gneiss”. | |
| Bedrock | General term to describe consolidated rock underneath the surface. Bedrock outcrop is where bedrock can be seen above the surface. | |
SGPOT_DESC | - | A summarized description of each mapping unit. | |
Thickness | - | Gives range of minimum and maximum thickness for sand and gravel deposit. | |
Thick_mod | - | The thickness modifier indicates that the thickness of the unit could exceed the value listed in the Thick_max field. | |
Thick_min | - | Describes the minimum thickness of the sand and gravel unit. | |
Thick_max | - | Describes the maximum thickness of the sand and gravel unit. | |
Overburden | - | Gives range of minimum and maximum thickness for overburden. | |
OB_MOD | - | The overburden modifier indicates that the thickness of the overburden exceeds the values listed in the Ob_max field. | |
OB_MIN | - | Describes the minimum thickness of the overburden covering the sand and gravel. | |
OB_MAX | - | Describes the maximum thickness of the overburden covering the sand and gravel. | |
MAP_LABEL | enumerated | 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 | |
| Ltd | Limited Potential for Sand and Gravel Resources | |
Landform | enumerated | The geological landform associated with each mapping unit. | |
| Alluvial Valley | Valley carved by flowing water like a river, stream, or creek valley. | |
| Collapse Feature | Landform that was deposited in or on glacial ice that subsequently collapsed | |
| End Moraine Complex | The terminal, or furthest, position of ice. This map unit includes end moraines that were either deposited by an accumulation of sediment and/or end moraines formed by glacial thrusting of older sediments and bedrock. | |
| Glacial Lake | Generally a broad flat or depressed area, formally occupied by a large body of water supplied by melting glacial ice. Characterized by fine sediments deposited in stagnant water. | |
| Glacial Lake/Delta | Landforms created as water flowed into a large glacial lake, depositing coarser grained sediments. | |
| 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. | |
| Alluvial Plain | Flat landform composed of sediments deposited by multiple flood events of a river. | |
| Alluvial Terrace | Former river floodplains that were abandoned as the river cut deeper into the landscape. | |
| Colluvial Feature | Sediment that accumulated at the base of a steep slope by falling from above. | |
| Moraine | This mapping unit includes sequences of till accumulated either at the end (end moraine) and/or the side (lateral moraine) of glacial ice. | |
| 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. | |
| Stagnation Feature | Features associated with the stagnation of a glacier. | |
| Outwash Feature | | |
| Outwash Channel | A landform consisting of stratified sediments, chiefly sand and gravel, removed or “washed out” from a glacier by meltwater, typically deposited in a large broad channel. | |
| Tunnel Valley | Valley carved by a subglacial stream. | |
| Alluvial Fan | A fan-shaped mass of alluvium deposited as the flow of a stream decreases in velocity, typically from a narrow canyon onto a valley floor. | |
| Bedrock Outcrop | Bedrock is a general term to describe consolidated rock underneath the surface. Bedrock outcrop is where the bedrock can be seen above the surface. | |
| Colluvium | Composed of unconsolidated sediments deposited at the base of steep slopes | |
Potential | enumerated | | |
| Significant Potential for Sand and Gravel Resources | Geologic units that are inferred to contain sand and gravel resource potential. These units exhibit the geologic characteristics associated with sand and gravel-bearing landforms. Existing gravel pit and MNDOT aggregate sources within these units are considered identified or known resources that increase the level of confidence for that mapping unit. These resources include the classes High and Moderate potential for sand and gravel deposits. | |
| Nonsignificant Potential for Sand and Gravel Resources | Units that generally have little or no potential for significant aggregate resources or lack sufficient data to support a classification of significant aggregate resources. These units typically contain clay, silt, fine sand, unsorted sediments (till), very thin layers of sand and gravel, or have significant overburden. Nonsignificant potential regions also coincide where bedrock is at or near the surface, or these units may include aggregate deposits that are too small to map. | |
Class | enumerated | | |
| High Potential for Sand and Gravel Resources | Includes landforms such as alluvial valleys, outwash channels, outwash features, and outwash terraces. Predominant sediment typically consists of gravel with sand to sand and gravel. The probability2 that a potential sand and gravel resource exists within any map unit is moderately high to very high. Deposit thickness ranges from 0-35+ feet with 0-5+ feet of overburden3. The sand and gravel resources occurring in this unit are moderate to very large in areal extent4 and the textural characteristics5 are moderately good to very good. The quality6 is moderate to high, relative to other sand and gravel resources within Redwood County. | |
| Moderate Potential for Sand and Gravel Resources | Includes landforms such alluvial valleys, outwash features, outwash channels, outwash terraces, ice contact features, and ground moraine. Predominant sediment ranges from sand with minor gravel to sand and gravel. The probability that a potential sand and gravel resource exists within any map unit is moderate to high. Deposit thickness is typically 0-25+ feet with 0-10+ feet of overburden. The sand and gravel resources occurring in this unit are small to very large in areal extent and the textural characteristics are moderate to good. The quality is typically moderately low to high relative to other sand and gravel resources within Redwood County. | |
| Low Potential for Sand and Gravel Resources | Includes landforms such as alluvial valleys, alluvial fans, colluvium, outwash features, outwash channels, outwash terraces, ice contact features, ground moraine, and modified ground moraine. Predominant sediment varies and can include sandy till, sand, silt, and sand with minor gravel. The probability that a significant sand and gravel resource exists within this unit is low to moderate. The thickness of the deposits is typically 0-15+ feet with overburden thickness ranging from 0-35+ feet. The sand and gravel resources occurring in this unit are very small to very large in areal extent and textural characteristics are poor to moderately good. The quality ranges from low to moderately high relative to other sand and gravel resources within Redwood County. | |
| Limited Potential for Sand and Gravel Resources | Includes landforms such alluvial valleys, alluvial fans, outwash features, outwash channels, outwash terraces, ice contact features, moraines, ground moraine, modified ground moraine, and bedrock outcrops. The deposits of this unit contain all or one of the following: clay with boulders (till), clay, silt, sand, and organics. The probability that a significant sand and gravel resource exists within this unit is very low to moderately low. The thickness of the deposits is typically 0-10+ feet with overburden thickness ranging from 0-50+ feet. The sand and gravel resources occurring in this unit are very small to moderately small in areal extent and textural characteristics are very poor to moderately poor. The quality ranges from very low to moderately low relative to other sand and gravel resources within Redwood County. A limited potential rating includes the circumstance where characteristics are unknown; there was insufficient data to give a higher ranking; limited access to an area for further investigation; and/or no obvious landform-sediment association. | |
Probability | - | The relative degree of certainty that sand and gravel exists within a unit. Based on air photo interpretations, field observations, CWI, presence of gravel pits, etc. Each unit is relative to the other units and range from very high to low. | |
Acreage | enumerated | The approximate size of the deposit in acres. | |
| Very Large | 30+ | |
| Large | 20-30 | |
| Moderately Large | 15-20 | |
| Moderately Small | 5-10 | |
| Moderate | 10-15 | |
| Small | 3-5 | |
| Very Small | < 3 | |
Texture | - | 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 MNDOT Pit sheets for more detail. | |
Quality | - | A relative scale of the quality of the sand and gravel (soundness, durability, and mineral makeup). | |
Dom_Litho | enumerated | 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 tan, silty loam with the indicator lithologies of shale and limestone 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 limestone and iron oxides. | |
| Granite | A felsic igneous rock that has medium to coarse crystalline texture. Includes granite, quartz monzonite, and granodiorite based on Minnesota Geological Survey bedrock descriptions. Referred to as “Sacred Heart Granite”. | |
| Granite/Gneiss | A coarse-grained crystalline and metamorphic rock. Includes foliated, biotite tonalitic to granodioritic gneiss based on Minnesota Geological Survey bedrock descriptions. Referred to as “Morton Gneiss”. | |