Table Name |
Field Name |
Begin Column |
Definition |
Valid Values |
Descriptions |
carlsgp.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 subsequent
information. Multiple values may be used in descriptions. |
General description of
the dominant sediment material for each mapping unit. |
|
Bedrock |
Presence of bedrock in
the form of an outcrop, boulder or below sediment. |
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Clay |
Clay is very
fine-grained sediment that is less than.0.004 mm in size. |
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Gravel |
Rock fragments of specific
particle size that is larger than 2 mm and less than 63 mm. |
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Organics |
Soil that contains
decaying organic matter. |
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Sand |
Rock fragments that
range in diameter from 0.0625 to 2 mm. |
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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. |
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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. |
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Silt |
Rock fragments that
have a diameter between 0.004 to 0.0625 mm. |
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Till |
A term used to describe
the unsorted sediment deposited by glaciers- contains a mixture of clay,
silt, sand, gravel and boulders. |
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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 Terrace |
Terrace deposited by
alluvial action. |
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Alluvial Valley |
Valley carved by
flowing water like a river, stream or creek valley. |
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Beach |
A feature that forms
along a shoreline that usually consists of sorted silt, sands, gravels, and
cobbles. |
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Collapsed Outwash
Channel |
An outwash channel is a
stream carrying glacial meltwater that deposited
sorted silts, sands, gravels, and cobbles.
Collapse is a term 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. |
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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. |
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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. |
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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. |
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Ice-Walled Lake |
Water retained in steep-sided
hole formed within a thick mass of stagnating ice. |
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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. |
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Lake Plain |
Characterized by a flat
topography consisting of sands, silts, and clays formed by the impoundment of
glacial meltwater forming a glacial lake. |
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Outwash Channel |
Stratified sediments, chiefly
silt, sand, and gravel, removed or “washed out” from a glacier by meltwater streams and deposited in a channel or valley. |
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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. |
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Outwash Terrace |
Terrace deposited by meltwater flowing through a glacial outwash channel.
Generally sediments deposited in terraces are sorted sand and gravel, silt is
possible and local till can be incorporated by erosional
activity. |
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Recessional Moraine |
Consisting of mostly till
as well as stratified sediments. A
recessional moraine forms during brief standstills in a glaciers retreat. |
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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. |
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Potential |
Text, 75 |
See Below |
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Significant 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. |
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Nonsignificant 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. |
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CLASS |
Text, 75 |
See Below |
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High Potential for Sand
and Gravel Resources |
Glaciofluvial features, outwash channels, terraces; ice contact
features like eskers, fans and kames; areas of coarse sorted material in end
moraines, beaches and alluvial terraces.
Deposits consist typically of sand and gravel. The probability2 that a
potential sand and gravel deposit exists within any mapping unit is
moderately high to very high. Thickness of the deposits ranges from 10 to 60+
feet with less than 15 feet of overburden.
These deposits are moderate to very large in areal
extent3 and the textural characteristics4 are good to
very good. The quality5 is
typically moderately high to very high relative to other deposits within
Carlton County and Fond du Lac Reservation. |
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Moderate Potential for
Sand and Gravel Resources |
Glaciofluvial features; outwash channels; and terraces;
ice contact features like eskers, fans and kames; beaches, end moraines;
alluvial valleys and alluvial terraces.
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 50+
feet with less than 20 feet of overburden.
These deposits are moderately small to moderately large in areal extent and the textural characteristics are
moderately good to good. The quality
is typically moderate to high. |
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Low Potential for Sand
and Gravel Resources |
Glaciofluvial features, outwash channels, terraces; ice
contact features like eskers, ice-walled lakes and kames; alluvial terraces
and valleys; beaches; lake plains; and moraines. 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
75+ feet with overburden thickness ranging from 0 to 50+ feet. These deposits are small to moderately
small in areal extent and the textural
characteristics are poor to moderately good.
The quality ranges from low to moderately high. |
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Limited Potential for
Sand and Gravel Resources |
Units
that include glacial features such as scoured glaciofluvial
channels, moraines, lake plains, and small alluvial features such as
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 to 200 feet. The sand and gravel deposits occurring in
this unit are very small to small in areal extent.
The textural characteristics are very poor to moderately poor with the
quality ranging from very low to moderately low. |
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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 |
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40-50 |
Moderately Large |
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30-40 |
Large |
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20-30 |
Moderate |
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10-20 |
Moderately Small |
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5-10 |
Small |
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<5 |
Very Small |
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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 |
|||||
Des Moines/Superior
Lobe Sediments |
The Des Moines Lobe flowed
from the northwest, down the Minnesota River valley to a glacial maximum in
Des Moines, Iowa. A sublobe, St. Louis sublobe,
flowed northeast into the extreme northwestern portion of Carlton County and
the extreme northwestern portion of Fond du Lac Reservation. Des Moines Lobe till is generally a tan, silty loam with indicator lithologies
of shale and limestone. 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. Stratigraphically Des Moines Lobe
sediments occur above Superior Lobe sediment (see description below). |
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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. |
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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 |
Number , 19, 5 |
0, 5, 10, 15, 20, 25,
30 |
Describes the minimum
thickness of the sand and gravel unit. |
||
THICK_MAX |
Number , 19, 5 |
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 |
Number , 19, 5 |
0, 3, 10, 20 |
Describes the minimum
thickness of the overburden covering the sand and gravel. |
||
OB_MAX |
Number , 19, 5 |
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 carlpits.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 |
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Mp |
Moderate Potential for
Sand and Gravel Resources |
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Lp |
Low Potential for Sand
and Gravel Resources |
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{Blank} |
Limited Potential for
Sand and Gravel Resources |