Table Name |
Field Name |
Begin Column |
Definition |
Valid Values |
Descriptions |
Lesuagppy.dbf |
Field_unit |
|
Integer,4 |
Values from 100 to 700. |
Unique identifier for
the field mapping units |
|
Fieldudesc |
|
Text, 60 |
e.g., Colluvium - Slope Wash/Debris;
Glaciofluvial Outwash Terrace - 50+ ft Sand w/ Gravel (Low); Holocene
Alluvium - Sand (>5 feet); Ice Contact - Sand and Gravel - Low Potential;
Sandstone - Quartz Sandstone - White; Till - Slope of Valley Wall. |
A short, summarized
description of the field mapping
units. |
|
Sgeo_plb |
|
Text, 80 |
Listed below as
Sgeo_plb (Sgeo_lab), youngest units to oldest units. |
The surficial geologic
unit shown on map Plate B. Mapping
units may be bedrock material, a glacial sediment, or a modern Holocene
sediment. |
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Colluvial Sediments
(Qcl) |
Clay, silt, sand, and
gravel, with occasional cobbles and boulders of varying composition, as well
as angular fragments of limestone and sandstone of varying sizes. The sediment is moderately- to
poorly-sorted, however, it occasionally contains thin (<6 inch) beds of
well-sorted alluvial material.
Colluvium is deposited at the foot of steep slopes where the bank
material has collapsed and become slightly washed by sheetwash and alluvial
processes. This colluvial sediment is
primarily located at the base of the steep till and bedrock walls paralleling
the Minnesota River. |
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Alluvial Flood Plain
Sediments (Qfp) |
Silt, fine sand, coarse
sand, gravel, and clay layers, overlying coarser sand and gravel layers and
lenses. The sediment is generally moderately-
to well-sorted and is interpreted to be alluvial overbank and stream bottom
deposits. Within this unit, coarser
sediment is typically found in abandoned and modern channels, point bars, and
river bars. Alluvial sediments exist
throughout the county in valleys, in low lying areas where drainage occurs as
channelized flow, and within the current flood plain of the Minnesota River. |
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Alluvial Fan Sediments
(Qaf) |
Stratified fine sand,
coarse sand, and gravel, with thin layers of silt and clay. The sediment is moderately well- to very
well-sorted. Coarser material is
typically found at the base of the fan (that is, the bottom of the deposit)
and near the mouth of the fan. The
sediment is generally deposited at the end of tributary streams where they
enter larger valleys, due to the change in slope and slowing of the water
flow, forming a cone shaped deposit.
Alluvial fan sediments primarily occur in the western part of the
county where smaller tributary streams enter the Minnesota River valley. |
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Alluvial Terrace
Sediments (Qat) |
Fine sand, coarse sand,
and gravel, with occasional layers of silt and clay. The sediment is moderately well- to
well-sorted with thin layers, lenses, and pockets of very well-sorted sands
and gravels. The terraces are
typically covered by 6 inches to 2 feet of silt, clay, and/or fine sand
layers derived from flood plain sediments.
Alluvial terrace sediments are found along tributary streams that
enter the Minnesota River, where moving water has cut through the pre-existing
till and glaciofluvial material and redeposited the sorted sands and gravels. |
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Glaciofluvial Outwash
Terrace Sediments (Qot) |
Stratified sand and
gravel with occasional cobbles and small boulders scattered throughout. The sediment is generally rounded to
well-rounded and well- to very-well sorted.
The sediment is interpreted to have been deposited in large distal
meltwater channels, such as the ones paralleling the Minnesota River near
Kasota and LeSueur. Glacial River
Warren, which drained Glacial Lake Agassiz, was responsible for the
deposition of these large terraces. |
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Glaciofluvial Outwash
Channel Sediments (Qoc) |
Stratified fine to
coarse sand and gravel, with occasional layers of silt, fine sand, and
cobbles scattered throughout. The sediment
is generally rounded to well-rounded and well- to very-well sorted. The sediment is interpreted to be derived
from large meltwater channels that ran on, within, and/or beneath the
retreating glacier and from the drainage channels of large glacial
lakes. Much of the sediment is
collapsed and discontinuous, which resulted from the melting and collapse of
the sediments overlying glacial ice or buried ice blocks. However, large continuous sand and gravel
outwash channel sediments are found near Waterville. |
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Outwash Channel
Sediments Modifying Till Sediments (Qto) |
Discontinuous, patchy,
and thin stratified fine to coarse sand and gravel, with occasional layers of
silt, fine sand, and cobbles, typically overlying unsorted till sediments
(unsorted clay, silt, sand, gravel, cobbles, and boulders). The outwash sediment is interpreted to
have been derived from smaller meltwater channels that ran on, within, and/or
underneath the retreating glacier and from the drainage channels of glacial
lakes. These outwash modified till
sediments are primarily located in the southeast part of the county. |
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Glaciolacustrine
Sediments over Till Sediments (Qgl) |
Alternating silt and
clay layers with layers of silt, clay, fine-sand, and medium sand overlying
unsorted till sediments (unsorted clay, silt, sand, gravel, cobbles, and
boulders). These sediments are
typically deposited as thin layers with distinctive summer and winter banding
called varves. The sediment is
interpreted to be derived from suspended material brought by meltwater
streams, running on top of melting glaciers, into ice walled glacial
lakes. These glaciolacustrine
sediments are scattered throughout the county and vary in size from a few
acres to nearly 9,000 acres, and vary in thickness from less than a few feet
to roughly 10 feet. |
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Ice Contact Sediments
(Qic) |
Stratified silt, fine
sand, coarse sand, and gravel, with occasional clay and silt layers. The sediment is generally rounded to
well-rounded and poorly- to well-sorted.
These sediments are deposited as features called eskers and
kames. These eskers are typically
long, narrow, sinuous ridges of stratified sand and gravel that were formed
as sub-glacial streams flowed between ice walls or in ice tunnels within the
stagnant glacier, and were left behind as the ice melted. The kame features are low mounds, knobs,
hummocks, or short irregular ridges also composed primarily of stratified
sand and gravel that were formed in low areas or holes on the surface of the
ice as fans or deltas. The smaller
ice contact sediments were not sorted as well and still contain a significant
amount of silt and clay within the sand and gravel. These sediments can be found throughout the county, however,
well developed eskers can be observed in the southeastern part of the county. |
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Till - Collapsed
Channel Sediments (Qcc) |
Till sediment (unsorted
clay, silt, sand, gravel, cobbles, and boulders), with occasional,
discontinuous and patchy, fine to coarse sand and gravel sediment. The sand and gravel sediment, overlying
the till, is all that remains of small outwash channels where supra-glacial
meltwater once carried large amounts of sand, gravel, and fine
sediments. The sediment has been
cleaned out of the channels and is often deposited as outwash channels further
down gradient. These collapsed
channel sediments can be observed in the southern and southeastern portions
of the county. |
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Till - Ground Moraine
Sediments - Low Relief (Qtl) |
Unsorted and
unstratified clay, silt, sand, and gravel, with scattered cobbles and boulders throughout. This till sediment (also called unsorted
drift) was deposited directly by and underneath the glacier without
subsequent reworking by meltwater.
The random melting of ice and deposition of material produced a
relatively flat to gently rolling, slightly hummocky topography that is
characteristic of a ground moraine. |
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Till – Stagnant Ice
Moraine Sediments - Moderate Relief (Qtm) |
Unsorted and
unstratified clay, silt, sand, and gravel, with scattered cobbles and boulders throughout. This till sediment was deposited directly
by and underneath the glacier without subsequent reworking by meltwater. The random melting of ice and deposition
of material produced a hummocky, undulating, or hilly topography. The topography is also characterized by
circular flat-topped hills, or plateaus, which are mostly till, but may be
capped with glaciolacustrine sediments. |
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Till – Stagnant Ice
Moraine Sediments - Higher Relief (Qth) |
Unsorted and
unstratified clay, silt, sand, and gravel, with scattered cobbles and
boulders throughout. This till
sediment was deposited directly by and underneath the glacier without
subsequent reworking by meltwater.
The random melting of ice and deposition of material produced a very
hummocky, undulating, or hilly topography characteristic of a stagnant ice
moraine. The topography is also
characterized by circular flat-topped hills, or plateaus, which are mostly
till, but are capped with glaciolacustrine sediments. There are several collapsed channels located
throughout this unit. |
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Till, Sand, and Gravel
Complex Sediments (Qts) |
Till (unsorted clay,
silt, sand, gravel, cobbles, and boulders) overlying and mixed with
relatively small, patchy, discontinuous, and thinly stratified, fine to
coarse sand and gravel, with occasional layers of clay, silt, and fine
sand. The area consists of small ice
contact and outwash deposits within a stagnant ice moraine. This area is interpreted to have been
dominated by meltwater drainage, however, a later glacial event covered the
outwash with till creating a complex of sand and gravel and till. The random melting of ice and deposition
of material produced a very hummocky, undulating, or hilly topography
characteristic of a stagnant ice moraine.
This complex of sediments can be observed in the southeastern corner
of the county. |
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Glaciofluvial Outwash
(Superior Lobe) Sediments (Qos) |
Stratified sand and
gravel, with occasional layers of cobbles, fine sand, and silt scattered
throughout. The sediment is generally
rounded to well-rounded and moderately well- to very well-sorted. The sediment is interpreted to be derived
from the meltwater drainage of the Superior Lobe (a much earlier glacial
advance that transported and deposited sediment from the northeast). This sediment is generally coarser than
any other outwash sediment in the county.
The sand and gravel sediment is primarily composed of igneous rocks
from the Lake Superior region, such as gabbros and basalts, whereas every
other sand and gravel deposit within the county consists primarily of
carbonates, granites, shales, and other rocks from sources to the
northwest. This sediment can only be
observed in the extreme northwestern portion of the county, where this buried
layer was exposed by the down-cutting of Glacial River Warren. |
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Limestone/Dolomite
(Ols) |
Light
brown, brownish gray to buff, fine- to medium-grained dolomitic limestone
with a silt-sized dolomite matrix.
Thin to thick bedded with variable color and texture both horizontally
and vertically. Some of the lower
beds are thicker and very well consolidated.
This unit is frequently porous and cavernous, with the caverns
commonly lined with calcite crystals.
Chert nodules and fossils are common throughout. This unit may contain small pockets of weathered
carbonate material near the surface. |
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Sandstone
(Css) |
White, yellowish to
light-brownish tan, and buff colored, medium to thick bedded, poorly
cemented, coarse- to medium-grained quartzose sandstone to dolomitic
sandstone. The upper unit contains
alternating layers of quartzose sandstone, dolomitic limestone, and dolomitic
sandstone and grades downward to fairly pure quartzose sandstone, then into
well-consolidated sandstone, and finally into loosely consolidated sandstone. The quartz purity of this unit increases
downward until it is > 95% pure quartz sandstone. This unit is currently being mined for
industrial quality sand within LeSueur County. |
|
Sgeo_lab |
|
Text, 4 |
Qaf, Qfp, Qat, Qcl,
Qos, Qoc, Qot, Qgl, Qic, Ols, Qto, Css, Qcc, Qtl, Qth, Qtm, Qts |
The label for the
surficial geology mapping unit used on map Plate B. |
|
Sgeo_age |
|
Text,30 |
Cambrian, Holocene,
Holocene/Ordovician, Holocene/Pleistocene, Ordovician, Pleistocene,
Pleistocene/Ordovician |
Describes the age of
the material encountered at the surface. |
|
Sgeo_proc |
|
Text, 40 |
|
The type of geological
process that deposited these features. |
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Alluvial |
Modern stream processes |
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Alluvial over
Glaciofluvial |
Modern stream processes
overlying glaciofluvial (glacial stream) processes |
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Bedrock |
Material deposited by
ancient seas during the Cambrian and Ordovician. |
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Colluvial |
Material that was
deposited as slope wash or slump along steep banks. |
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Glacial |
Unsorted glacial
material deposited in place. |
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Glacial over
Glaciofluvial |
Unsorted glacial
material deposited over glacial sediments that have been sorted by meltwater. |
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Glaciofluvial |
Glacial sediments that
have been sorted by meltwater. |
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Glaciolacustrine |
Sediments deposited at
the bottom of a glacial lake. |
|
Sgeo_feat |
|
Text, 50 |
Alluvial fan, Alluvial
terrace, Bedrock, Collapsed channel, Colluvial slope, Flood plain, Glacial
lake bed, Ground moraine, Ice contact, Outwash channel, Outwash terrace, Sand
bar, Stagnant ice moraine. |
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, 40 |
e.g., Clay, silt, and
sand over till; Sand; Sand and gravel; Limestone; Till with patchy sand and
gravel. |
The dominant type of
material encountered in the surficial geologic unit. |
|
Sg_sigpot |
|
Text, 50 |
Potential Sand and
Gravel Resources; Potential Crushed Stone Resource; Limited Potential for
Aggregate Resources. |
Significant
Aggregate Resources Deposits are defined as those deposits most likely to be
explored and evaluated for future commercial use. They include all the moderately and highly desirable sand,
gravel, and crushed stone deposits as well as very large areas of finer sand
and gravel that could be blended with coarser material to make more highly
desirable deposits. |
|
Sg_potpla |
|
Text,100 |
e.g., Highly Desirable
Sand and Gravel Deposits; Less Desirable Sand and Gravel Deposits/Moderately
Desirable Crushed Stone Deposits; Limited Potential Aggregate Resources. |
The aggregate resource
potential, combined from the Sg_pota_sg and Sg_pota_cs fields. |
|
Sg_pota_sg |
|
Text,50 |
|
The aggregate resource
potential for sand and gravel, as shown on map Plate A. From the legend on Plate A…. POTENTIAL
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 indicate identified or known resources. The geologic units having potential for sand and gravel include
alluvial features (flood plains, terraces, and fans), glacial outwash
features (channels and terraces), and ice-contact features (eskers and
kames). These units typically contain
sorted sand and gravel with little silt or clay. |
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Highly Desirable Sand
and Gravel Deposits |
Glaciofluvial
features, such as terraces and outwash channels. These deposits are very
large in areal extent. These deposits
consist of sand and gravel with thicknesses typically ranging from 15 to 75+
feet, with less than 5 feet of overburden.
The probability that a potential sand and gravel deposit exists within
this unit is high to very high. The
textural characteristics of these deposits are classified as good to very
good. The quality is typically
moderately high to very high relative to all deposits within LeSueur County. |
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Moderately Desirable
Sand and Gravel Deposits |
Glaciofluvial
features, such as outwash channels and terraces; ice-contact features, such
as eskers and kames; as well as Holocene age terraces, floodplains, and
fans. These deposits are moderately
small to large in areal extent with sand and gravel thicknesses typically
ranging from 10 to 50+ feet, with less than 10 feet of overburden. The probability that a potential sand and
gravel deposit exists within this unit is moderately high to very high. The textural characteristics of these
deposits are moderate to very good, with the quality ranging from moderately
high to high. |
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Less Desirable Sand and
Gravel Deposits |
Glaciofluvial
features, such as outwash channels and terraces; ice-contact features, such
as eskers and kames; and alluvial features such as flood plains, terraces,
fans, and sand bars. These deposits
are moderately small to very large in areal extent and consist of sand and
fine sand with thicknesses ranging from 0 to 50+ feet, with overburden
thicknesses between 0 to 40+ feet.
The probability that a potential sand and gravel deposit exists within
this unit is moderate to very high.
The textural characteristics of these deposits are moderately poor to
good, with the quality ranging from moderately low to high. |
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Limited Potential Sand
and Gravel Deposits or Limited Potential for
Aggregate Deposits |
Units
that include glacial features such as collapsed glaciofluvial channels,
ground moraines, glacial lake beds, colluvial slopes, and small alluvial
features such as flood plains and streams.
The probability that a significant aggregate deposit exists within
this unit is very low to moderate.
The aggregate deposits occurring in this unit are very small to
moderately small in areal extent and typically consist of finer material
(sand with some gravel). The
thicknesses of these aggregate deposits are typically less than 20 feet, with
overburden thicknesses sometimes reaching over 100 feet. The textural characteristics are poor to
moderately poor with the quality ranging from low to moderate. These units also contain carbonate bedrock
units with an overburden thickness of greater than 50 feet. In a few areas on the map, a dotted
pattern (indicating crushed stone resources potential) can be seen, lying
over this mapping unit. In this case,
there is crushed stone potential, but there is limited sand and gravel
potential. |
|
Sg_pota_cs |
|
Text,50 |
|
The aggregate resource
potential for crushed stone, as shown on map Plate A. From the legend on Plate A… POTENTIAL
CRUSHED STONE RESOURCES: Carbonate
(limestones and dolomites) bedrock from the Prairie du Chien Group and
sandstone bedrock from the Jordan Sandstone Formation that are suitable for
crushing. These units are inferred to
be relatively thick (10 to 50+ feet), with overburden thicknesses ranging
from 0 to 50 feet. Quarries located
within these units indicate identified or known resources. |
|
|
|
|
Highly Desirable
Crushed Stone Deposits |
Carbonate
(limestones and dolomites) bedrock units that are very large in areal extent,
and contain materials suitable for crushing.
These units have thicknesses ranging from 30 to 50+ feet, with
overburden thicknesses typically less than 10 feet. These units have a very high probability of containing
potential crushed stone deposits. The
quality of these units is high. |
|
|
|
|
Moderately Desirable
Crushed Stone Deposits |
Carbonate
(limestones and dolomites) bedrock units that are moderate to very large in
areal extent, and contain materials suitable for crushing. These units have thicknesses ranging from
20 to 40+ feet, with overburden thicknesses typically less than 10 feet. These units have a high to very high
probability of containing potential crushed stone deposits. The quality of these units is high. |
|
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|
Less Desirable Crushed
Stone Deposits |
Carbonate
(limestones and dolomites) and sandstone bedrock units that are moderately
large to very large in areal extent, and contain materials suitable for
crushing. These units have
thicknesses ranging from 10 to 50+ feet, with overburden thicknesses ranging
from 0 to 50 feet. These units have a
moderately high to very high probability of containing potential crushed
stone deposits. The quality of these
units is moderately high to very high. |
|
Sg_prob |
|
Text, 20 |
Very High, High,
Moderately High, Moderate, Moderately Low, 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, Large,
Moderately large, Moderate, Moderately small, Small |
The relative size of
the sand and gravel deposit |
|
Size_in_ac |
|
Text, 7 |
>50, 40-50, 30-40,
20-30, 10-20, 5-10 |
The size of the deposit
in acres. |
|
Sg_thickmn |
|
Integer, 4 |
0, 5, 10, 15, 20, 25,
30 |
Describes the minimum
thickness of the sand and gravel unit. |
|
Sg_thickmx |
|
Integer, 4 |
5, 10, 15, 20, 25, 30,
40, 50, 75 |
Describes the maximum
thickness of the sand and gravel unit. |
|
Sg_thickmd |
|
Text,1 |
+ |
The sg_thickness
modifier indicates that the thickness of the unit exceeds the value listed in
the Sg_thickmx field. |
|
Sg_overmin |
|
Integer,4 |
0, 3, 10, 20 |
Describes the minimum
thickness of the overburden covering the sand and gravel. |
|
Sg_overmax |
|
Integer,4 |
1, 3, 5, 10, 15, 20,
30, 40, 50 |
Describes the maximum
thickness of the overburden covering the sand and gravel. |
|
Sg_overmod |
|
Text,1 |
+ |
The sg_overburden
modifier indicates that the thickness of the overburden exceeds the values
listed in the Sg_overmax field. |
|
Sg_texture |
|
Text, 20 |
Very Good, Good,
Moderately Good, Moderate/Good, Moderate, Moderately Poor, Poor/Good, 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 High, High,
Moderately High, Moderate/High, Moderate, Moderately Low, Low/High, Low |
A relative scale of the
quality of the sand and gravel (soundness, durability, and mineral
makeup). Determined from MN/DOT pit
sheets. |
|
Sg_thick |
|
Text, 15 |
e.g., 0-5, 5-30+,
20-40, 25-75+ |
The assumed range of
thickness of the sand and gravel deposit (in feet). A combination of the Sg_thickmn, Sg_thickmx, and Sg_thickmd
fields. |
|
Sg_overbdn |
|
Text, 15 |
e.g., 0-1, 0-20+, 10-20, 20-40+ |
The assumed range of
overburden thickness of a sand and gravel deposit (in feet). A combination of the Sg_overmin,
Sg_overmax, and Sg_overmod fields. |