THE KANEVILLE ESKER
A
Qualifying Paper
Submitted to the Graduate School
in Partial Fulfillment of the Requirements
for the Degree of
Master of Science in Geology
Department of Earth Sciences
by
Michael T. Lukert
NORTHERN ILLINOIS UNIVERSITY
De Kalb, Illinois
JUI.~,
1962
~ e a dand a ~ r o- v e d by
---&--
44!&r4
-2/2&!!
-7!~d63~
A l i n e a r r i d g e c o n s i s t i r l g o f sand aiLd ..ravel,
located
i n s o u t h - c e n t r a l Kane County, I l l i n o i s , was i n t e r p r e t e d a s
a n e s k e r i n 1899.
cepted.
T h i s i n t e r p r e t a t i o n was g e n e r a l l y ac-
R e c e n t l y , however, i t h a s been s u ~ y e s t c dt h a t t h e
landform may have o r i g i n a t e d a s a c p e v a s s e S i l L l n g o r as an
ice-marginal deposit.
The t o p o g r a p h i c c o n f i - g d - r a t ijn o f t h e
f e a t u r e and t h e a s s o c i a t e d landforms a r e n ~ s tp l a u s i b l y exp l a i n e d by t h e e s k e r i n e i n t e r p r e t a t i o n .
The s e d i m e n t s com-
p r i s i n g t h e l a n d f o r m a r e c h a r a c t e r i s t i c of i c e - c o n t a c t d e posits,
The a l i g n m e n t of t h e s e s e a i m e n t s and t h e n a t u r e
and l o c a t i o n of t h e a s s o c i a t e d m a t e r i a l s f u r t h e r s u p p o r t
t h e eskerine Interpretation,
f i l l overlying the f l a n k s o f
t h e e s k e r i s b e l i e v e d t o be t h e G i l b e r t s till d e s c r i b e d by
Powers.
The c o n t a c t r e l a t i o n s h i p s between t h e t i l l and t h e
eskarine sediments i n d i c a t e t h a t b o t h >sere d e p o s i t e d by t h e
same i c e s h e e t .
TAE3LE OF CONTENTS
Page
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Table of Contents . . .
List of Illustrations .
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List of Tables
Abstract
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iii
CHAPTERS
I.
INTRODUCTION
.............
Previous works
Previous interpretations
Statement of problem
Field and laboratory methods and
procedures
Acknowledgments
11.
DISTRIBUTION AND FORM
. . . . . . . .
.
Location
Topographic form and areal extent
Associated landforms
Discussion
Conclusions
111.
CHARACTERISTICS OF THE SEDIMENTS
. .
General characteristics
Sedimentary structure
Particle orientation
Sediment composition
Associated deposits and contact relationships
Conclusions
IV
.
RELATIONSHIPS OF THE KANEVILLE E S m TO
THE GLACIAL HISTORY OF THE A R m
.
.
Glacial history of the area
Stratigraphic position of the Kaneville
esker
Conclusions
6
V.
.......
SUMMARY AND CONCLUSIONS
REFEEENCES CITED
.............
LIST OF ILLUSTRATIONS
Figure
. ..
...
. . ..
.
.. . . .
Sand and gravel removal operations
Physiographic Divisions of Illinois
Eskerine form of the middle section
.
Small kame in Sec. 31
. . . . .
Small kame in Sec. 31 . .
.
.
Stratification and lateral variation in
. . . . . . . . . . . . .
grain size
Vertical variation in grain size
.
Slump structure in the Kaneville esker
Cobble orientation
.
. .
Glacial geology in northeastern Illinois
..
.
.... ..
....
..
LIST OF TABUS
Table
1.
SIZE RANGES OF THE SEDIMENTS OF THE KANEVILLE ESKER
. . . . . . . . . . . . .
2.
PETROLOGIC COMPOSITION OF SEDIMENTS OF
KANEVILLE ESKER.
.
......... ..
CHAPTER I
INTRODUCTION
Previous works.
The Kaneville esker was first des-
cribed by Leverett (1899, p. 284-286) in his well-known monograph on the glacial geology of Illinois. A more detailed
discussion of the feature is found in an unpublished manuscript by Leighton, Powers, MacClintock and Workman (1931,
p.
66-75). Additional information concerning the location
and areal extent of the landform may be found on maps accompanying publications by Block (1960, pl. 1); Suter, Bergstrom, et al. (1959, fig. 5); Fryxell (1927, pl. 1); and
Hopkins, Mosier, -et al. (1917, Soil Survey Map of Kane
County, Northern Sheet )
.
Previous interpretations. Thwaites (1961, p. 52) describes an esker as "an irregular crested ridge of water
sorted drift" deposited by "a glacial stream either in an
ice tunnel or an open crack."
Both Leverett and Powers in-
terpreted the topographic form and the materials associated
with the feature as being accordant with the description of
an esker and designated it as such.
Recently, however, these has been speculation as to
whether or not the feature called the Kaneville eskerl is
indeed an esker,
Dr. George E. Ekblaw of the Illinois State
Geological Survey has advanced the theory that the Kaneville
esker might actually be an ice-marginal deposit, laid down
at the edge of z lobe of ice during a pause in the retreat
of the lobe (1962, personal communication)'.
Still another
hypothesis suggests that the feature may have originated as
a creuasse filling in the ice (~oardman,Odom, and Wilson,
1962, P. 9).
Statement of problem.
I
The primary purpose of this
paper is to attempt to describe the areal extent, topographic form, and the sedimentary characteristics of the
Kaneville esker and to determine its mode of origin and
stratigraphic position.
Field and laboratory methods and procedures.
Initially
an examination was made of the topographic form and all significant exposures of materials associated with the feature.
Extensive excavations for the purpose of gravel removal have
made many exposures of the interior of the deposit available
1. While the actual mode of origin is one of the topics of
this paper, the landform under consideration will occasionally be referred to as "the Kaneville esker" in the text.
This permits easy reference to the landform and avoids needless repetition of descriptive terms.
2. The ice-marginal theory, as used here, fs meant to indicate the construction of a series of coalescing frontal
kames deposited by meltwater flowing off the edge of the ice
(fig. 1 and pl. 1).
Such exposures allow a high degree of
familiarization with the materials comprising the feature.
Topographic maps and aerial photographs were utilized in
locating outcrops and in defining the topographic configuration of the landform.
Cobble-sized particles were examined in order to determine the orientation of their long axes.
In accordance
with basic principles of physics, an elongate body in a
fluid medium should become aligned so as to offer the least
resistance to that medium.
If this direction of alignment
can be determined, the direction of flow may be limited to
two possible directions.
It is believed that additional in-
formation regarding the topographic form of the feature
eliminates one of these two possible directions of flow,
The long axis orientations of the cobbles were determined
at fresh exposures in which the material was known to be in
place.
Examination of the outcrops along and within the deposit revealed that the materials were heterogeneous in
size.
Consequently, the writer concluded that samples col-
lected from slumped materials at the base of fresh exposures would provide a reliable sample for sediment analysis.
The samples were split according to the procedure outlined
by W. C. Krumbein (1938, p. 44), and the remaining sample
material was mechanically sieved by means of a Ro-Tap shaking machine.
The sieve sizes ranged from 32 mrn. to 1/32 mm.
----
7
-
Fig. 1. Sand and gravel removal
operations at location 2.
-5Analysis of samples was undertaken to show in very general
terms the approximate size and composition of the sediments
associated with the Kaneville esker.
The frequency of all
particles larger than 2 mrn. was recorded under the following
categories:
limestone, dolomite, mafic rocks, felsic rocks,
metamorphic rocks, chert, and others.
The areal extent of the landform was mapped primarily
on the basis of topographic expression.
Block's map of the
sand and gravel resources of Kane County (1960, pl. l),
aerial photographs, field exposures, and auger borings were
utilized in mapping the feature.
Field data, along with ap-
proximate locations of active and inactive gravel pits, were
plotted on expanded portions of the topographic map of the
Geneva Quadrangle.
Acknowledgments.
The writer wishes to express his
gratitude and appreciation to Dr. Harold A. Winters, Assistant Pr~fessorof the Earth Sciences, whose contributions of
time and knowledge were essential to the preparation of this
manuscript.
Special thanks are extended to the writer's wife, m a lou, without whose aid and encouragement this paper would
not have been possible.
CHAPTER I1
DISTRIBUTION AND FORM
Location.
The landform designated as the Kaneville
esker is located in the south-central portion of Kane County
about five miles west-northwest of Aurora, Illinois. The
feature is situated in the extreme northeast part of the
Bloomington Ridged Plain (fig. 2) as defined by Leighton,
Ekblaw, and Horberg (1948, p. 24).
Topographic form and areal extent.
The feature dis-
-7
plays an arcuate form, convex southwestward, extending from
the NE. l/4 of Sec. 15, T. 38 N., R. 7 E. to the SE. 1/4
NE. l/4 Sec. 25, T. 39 N., R. 6 E. (pl. 2).
The landform
may be divided into three distinct topographic sections:
a
southeast section, a middle section, and a northwest section.
The southeast section extends from the NE. 1/4 NE. I/&
Sec. 15, T. 3 8 ~ . ,R. 7 E . to the NE. 1/4 SW. l/4 See. 9,
T. 38 N., R. 7 E.
The topographic form of the deposit in
this section has been interpreted from the topographic map
since the landforms associated with the deposit have been
destroyed by extensive removal of sand and gravel by man.
This southeast section appears to have consisted of several
small, somewhat elongate hillocks.
These small knolls rose
20 and 50 feet above the floor of the valley of Blackberry
-6-
Fig. 2
PHYSIOGRAPHIC DIVISIONS OF ILLINOIS
(Reprinted from Illinois State Geological Survey Report of
Investigations 1 2 9 , "Physiographic Divisions of Illinois, "
by M M . Leighton, George E Ekblaw, and Leland Horberg)
.
.
-8 -
Creek, which follows the trend of the landform for much of
its length.
The crests of the hillocks had an elevation
between 690 and 700 feet above sea level at the extreme
southeast end of the feature.
The middle section extends from the SW. 1/4 NW. 1/4 of
Sec. 9 to the SW. l/4 NW. 1/4 SW. l/4 Sec.
5, T. 38 N., R.
7 E. Between these points the feature consists of an elongate, irregularly crested ridge (fig. 3). This ridge is not
continuous, but is breached at several points.
The most no-
table break is located in the western part of Sec. 9, T. 38
N., R.
7 E., where the southeast-flowing Blackberry Creek
changes its course from the north to the south side of the
feature (pls. 1 and 2).
The ridge
the adjacent plain, the height i
The width varies from about 400
and the sides assume a slope of
The northwest section ext
of Sec.
5, T. 38 N., R. 7 E. to the northeast part of Sec.
25, T. 39 N., R. 6
E.
In this area the landforms become in-
creasingly complex and do not display the well-defined eskerine form of the middle section.
The feature consists of
a linear series of coalescing kame-like landforms that range
from 50 to
70 feet in height and may exceed
100 feet in
width.
Associated landforms.
Extending north and northwest
from the Kaneville esker is a landform possessing the
I
--
--
-
--
Fig. 3. Eskerine form of middle
section. View of location 5 looking
southeast from location 3A.
-
-10-
Leverett (1899,
topographic configuration of a delta.
p. 284) interpreted the feature to be a delta.
(Leighton, Powers -et al., 1931, p.
Powers
72) agreed with Leverett's
interpretation and correlated the delta with a pro-glacial
lake which he called Lake Pingree.
The maximum elevation
of this postulated delta is approximately 810 feet.
The
maximum elevation of the hillocks at the extreme southeast
end of the Kaneville esker, described previously, is 700
feet.
Thus the proposed delta has a maximum elevation 110
feet higher than that of the hillocks comprising the southeast portion of the feature.
On the southwest flank of the Kaneville esker (SE, l/4
SE.
1/4 SW. 1/4 Sec. 31, T. 39 N., R. 7 E . See pls. 1 and
2) is a small conical hill which rises about
the surrounding landscape (figs. 4 and
40 feet above
5). This feature is
interpreted to be a small kame.
Another particularly interesting landform found in the
NW. 1/2NW. 1 4 Sec. 30, T. 39N., R.
7 E . (pls. 1 and2),
consists of a small ridge approximately one-quarter of a
mile in length, which extends eastward and terminates in a
small hill.
The ridge proper has a height of about 30 feet,
and the hill rises 10 to 15 feet above the ridge.
This
ridge may mark the position of a small esker tunnel or crevasse through which meltwater flowed.
The small hill on the
eastern end of the ridge could represent a kame marking the
head of the west flowing meltwater stream.
r
-
--
--
---A
-
Fig. 4. Small kame in S e c . 31,
looking southwest.
Fig. 5. Small kame in S e c . 31,
looking northwest.
--
Discussion.
The linear arrangement of the landform
implies lateral limitation of the area of deposition.
This
lateral limitation undoubtedly resulted from the presence of
glacial ice on at least one and possibly both sides of the
deposit.
The landform itself could have originated as an
esker, as an ice-marginal featureJ3 or as a crevasse
filling.
Consequently, each interpretation will be examined
in order to determine which is most plausible.
If the eskerine interpretation of origin is accepted,
the length and linear pattern of the landform are easily explained.
The sparsity of eskerine forms in the southeast
section of the feature could be accounted for by a lack of
deposition in this area, especially since this portion is at
or near the assumed point of origin.
In addition, Powers
(Leigl-iton, Powers, et al., 1931, p. 75) expressed the belief
that the southeast section was overridden by a later advance
of glacial ice which could have altered any pre-existing
landforms.
I
The topographic configuration of the middle section
strongly suggests an eskerine origin.
This section displays
the irregular longitudinal profile and sharp crest that is
characteristic of eskers.
I
The northwest section appears to be closely related to
the eskerine forms of the middle section, but a significant
-13topographic difference exists between the two sections.
The rugged topography of the northwest section consists of
many closely spaced gravel hills.
The area within which the
hills occur is fan-shaped, widening toward the adjacent
delta on the north and narrowing toward the eskerine forms
of the middle section on the south (pl. 2).
The writer believes that the landforms of the northwest section were constructed at or near the mouth of the
esker stream in direct contact, at least in part, with glacial ice.
Furthermore, the northwest section may represent
a transition zone between the pro-glacial delta form to the
north and the ice-restricted eskerine features of the middle
section.
If the above interpretation is correct, the land-
forms of the northwest section, while not eskerine in character, lend support to the theory that the Kaneville esker
is actually an esker and not an ice-marginal feature or a
crevasse filling.
Perhaps the principal objection to the eskerine theory
is related to the difference in height between the head and
the mouth of the stream that the meltwater would have to
overcome.
The present position and elevation of landforms
associated with the feature indicate that the meltwater may
have flowed upslope more than 100 feet in a horizontal distance of about five miles.
While great hydraulic pressure
would be necessary to overcome the gradient, this situation
does not discount the possibility of eskerine origin
according to Flint (1957, p. 155) and Thwaites (1961, p. 53).
It also should be noted that the apparent gradient on the
present topography does not necessarily represent the original gradient.
The landforms of the esker may have been
superimposed upon an uneven subglacial topography.
The ice-marginal theory4 of origin has been postulated
principally on the basis of (1) the arcuate pattern of the
landform and (2) the possibility that morainal trends to the
southwest might conform to this pattern ( ~ e o r ~E.
e Ekblaw,
1962, personal communication).
The nature of landforms in the southeast section of the
feature lends support to this interpretation. The numerous
hillocks may have been formed in areas of concentrated deposition of material by meltwater streams flowing from the
glacier to form a linear group of coalescing frontal kames.
Later glaciation could have altered the landforms.
The middle section of the feature is more difficult to explain.
The construction of an ice-marginal feature possessing
such linear continuity and cross-sectional symmetry would require conditions that are difficult to visualize.
If the ice-marginal theory is accepted, the landforms in
the northwest section could have originated in the same manner
as those of the southeast section.
That is, the tract of kame-
like hills would mark the former position of the actual ice
II
margin.
4. See footnote 2, p. 2.
The relationship between the Kaneville esker and the deltaic topography is difficult to explain if the ice-marginal
theory is assumed to be correct.
Possibly the deltaic topo-
graphic form is unrelated to the feature under consideration.
However, the proximity and form of the two features would seem
to indicate something more than fortuitous location.
If the
deltaic landform is related to the origin of the Kaneville esker, the ice-marginal hypothesis must include some explanation
of the flow of meltwater uphill without benefit of the waterhead and enclosed tunnel inherent in the eskerine interpretation.
The linear pattern of the landform has led to the suggestion that the Kaneville esker may have originated as a crevasse
filling (~oardman,Odom, and Wilson, 1962, p. 9).
If this hy-
pothesis is accepted, the difference in elevation between the
northwest and the southeast ends of the landform implies a
southeast flow of meltwater.
Such a flow should be expressed
in an abundance of landforms resulting from fluvial deposition
in the southeast section.
The opposite is true, however, since
such landforms are scarce in the southeast section and abundant
in the northwest.
Superimposition of the crevasse sediments
upon the subglacial topography might adequately explain the relationship between the delta and the ice-contact landform.
If
superimposition is assumed, the gradient along the present landform may be the reverse of the gradient present during the construction of the feature.
The irregular crest of the landform is not in harmony with
the crevasse filling interpretation.
The crests of crevasse
-16fillings are usually smooth in longitudinal profile.
In addi-
tion, the sharp-crested cross-sectional profile of this feature
presents a striking contrast to the flat crest commonly associated with crevasse fillings. In almost every respect, the topographic configuration of the landform is in complete contradiction to this hypothesis.
Unless superimposition of the crevasse sediments is assumed, the crevasse filling interpretation does not account for
the position of the deltaic landform at the northwest end of
the feature.
A flow of water to the northwest must be postula-
ted or the deltaic topography must be assumed to be unrelated
to the landform under consideration.
The length of the land-
form itself, approximately five miles, is somewhat greater than
that of most crevasse fillings
lint, 1952 p. 1s and Thwaites,
1961, p.52). The arcuate pattern of the landform is also anomalous with the nearly straight trend typical of known crevasse
fillings (Thwaites, 1961, p. 52).
Conclusions. Neither the ice-marginal nor the crevasse
filling interpretation adequately explains the topographic
forms associated with the Kaneville esker.
The eskerine in-
terpretation of origin, however, provides a satisfactory explanation for the form and configuration of the landform.
In
addition, the eskerine interpretation helps to account for the
-
existence and placement of nearby ice-contact landforms that
appear to be related to the feature. Further evidence to support this conclusion will be furnished in an examination of the
sediments associated with the landform.
CHARACTERISTICS OF THE SEDIMENTS
General characteristics.
Ice-contact deposits are cha-
racterized by complex stratification and cross-bedding,
great variation and abrupt changes in grain size, and slumping of the sediments.
Such characteristics are common in
the sediments associated with the linear tract of sand and
gravel known as the Kaneville esker.
Sedi-mentary structure.
Examination of the sediments
reveals that the stratification is more or less horizontal.
Near the flanks of the landform, however, some bedding
planes are approximately p
the feature.
In general, the stratification is co
of lenses of coarse gravel interfingering with layers of
sand (figs. 6 and
7). Abundant cross-bedding, ranging from
large to small scale, was observed at every exposure.
Chan-
nel deposits and cut-and-fill deposits were also observed.
Slump structures in ice-contact deposits result from
the melting of ice that provides support for the sedimentary
materials.
Such structures may be found in the deposit
under consideration (fig. 8). At some locations the bedding
along the flanks of the feature was found to dip away from
-
-
.
--
--
--,
Fig. 6, Stratification and
lateral.variation in grain size.
-
-
-
-
--
,
-_ . --
---
- ----
--
Fig. 7. Vertical variation in
grain size.
-
-
-
L-
Fig. 8. Slump structure in the
Kaneville esker, View is northwest at
location 2.
the center of the deposit, indicating slumping along the
sides.
Most of the slump structures observed indicate col-
lapse' to the northeast.
Good exposures on the southwest
flank of the landform did not exist at the time of this
study.
Consequently, the presence or absence of collapse to
the southwest could not be determined.
Particle orientation.
Orientation of the long axes of
fifty cobble-sized particles was determined at each of six
locations.
The results, graphically described in figure 9,
indicate that the flow of the depositional medium was, in
general, parallel to the strike of the landform.
Measure-
ments were made at locations 2, 3, 3A, 4, and 11 of material
that was exposed in fresh outcrops which bad not experienced
slumping (pl. 1).
Two determinations separated by a verti-
cal distance of at least 50 feet, were made at location 2:
one in material located in the lower part of the pit and the
other near the top.
These two measurements suggest that the
orientation of cobble aixes does not differ significantly
with an increase in elevation at this location.
Sediment composition.
The size frequency of the sedi-
ments are presented in Table 1.
The sediments are composed
predominantly of coarse materials, that is, greater than the
size of fine sand (1/4 mrn.).
Pebble counts were limited to particles larger in size
than very coarse sand (2 mm.).
counts are shown in Table 2.
The results of the pebble
Dolomite, believed to be
-23rocks comprise about ten per cent of the sediments.
Metamor-
phic rocks, limestone, and chert are present only in minor
amounts
.
At locations 3,
5, 9, lo, 11, and 11A the materials at
the base of the exposures are highly stained by iron oxide.
The stratification, composition, structure, and continuity
of the stained sediment indicates that they are associated
with the landform and are not remnants of a previous deposit.
At location 5, a zone of well-cemented sand and gravel also
occurs in the lower part of the exposures.
The cementing
agent is calcite, and the nature of the material is more
typical of conglomerate than of unconsolidated materials
commonly associated with ice-contact deposits.
The iron
oxide stain and the cemented gravel are believed to be related in some manner to the groundwater table.
Associated deposits and contact relationships.
Till is
found along both sides of the glacio-fluvial sediments and
in some instances overlies the gravel along the flanks of
the landform.
At no outcrop was the till found to extend
completely over the water-deposited materials.
Contacts be-
tween the till and the waterlaid sediments are known to occur at locations 3,
5, 7, 9,
10, and 11A (pl. 1).
consists of clay with much sand and some silt.
The till
In addition,
many dolomite pebbles and some fragments of igneous rocks
occur.
Cobbles and boulders are rare.
The color of the
till varies from light-brown to brown with a reddish cast.
-24The upper portion of the till is leached, but the lower portion is calcareous.
Where exposed, the till is rarely mope
than six feet thick.
At one location within the southeast
part of the landform, the till is interrupted by a thin,
nearly horizontal, discontinuous carbonaceous zone.
The
till above this carbonaceous layer is not obviously different from the till below.
It is possible, however, that the
carbonaceous zone separates two tills of different age.
This is the only indication of possible later glaciation observed by the present writer.
At several locations near the northwest end of the
Kaneville esker, the stratified sands and gravels merge
horizontally and vertically with slumped, laminated, carbonaceous silts and clays.
These fine sediments contain oc-
casional pebbles and cobbles.
The nature of these sediments
suggests deposition in calmer water than that in which the
sand and gravel were deposited.
The transitional contact
between the fine sediments and the sands and gravels indicates that both were deposited by meltwater associated with
the esker stream.
The nature and occurrence of the silts
and clays may be explained in the following manner.
The per-
iodic occurrence of unusual volumes of meltwater could cause
the esker stream to overflow its normal channel.
During
these periods of high water, sand and gravel would continue
to be deposited in the main channel as bedload.
In addition,
silts and clays carried in suspension by the stream could
- 25have been deposited on the uneven surface of the adjacent
ice.
Under these conditions, it is possible that a transi-
tional zone might occur between the coarse and fine sediments.
The presence of occasional coarse particles in the
fine sediments could result from the melting of floating
blocks of glacial ice.
A decrease in the volume of water
would leave the clays and silts resting, at least in part,
on the flanking ice.
Subsequent melting of the supporting
glacial ice would permit the fine sediments to be superimposed directly on the underlying glacial drift.
This inter-
pretation would account for the contorted laminations of the
silts and clays and the gradational contact between the
coarse and fine sediments.
The abundant carbonaceous material may represent organic matter present in the depositional environment in
which the silts and clays were laid down.
There is a pos-
sibility, however, that the organic material was transported
from the surface of the ice.
The presence of the organic
remains may be a result of one or both of these conditions.
the carbonaceous matter
The character and concentration of
in such a small area makes it doubtful that the organic material could have been transported any great distance.
The surficial sediments associated with the deltaic
landform to the northwest consist of brown clay and some
sand and silt.
This material is underlain by sand and other
coarse sediments that were difficult to penetrate with a
hand-auger.
-26The materials comprising the east-west ridge in Section
30 (pls. 1 and 2) were found to be sand and gravel, very
similar in nature to the sediments of the Kaneville esker.
Likewise, the small kame in Section 31 was found to be composed of sand and gravel.
In the kame, however, there ap-
pears to be a larger proportion of fine material than in the
eskerine landform.
Conclusions.
The structure and composition of the sedi-
ments observed do not provide conclusive evidence for or
against any of the proposed theories of origin.
Slump struc-
tures and cross-bedding are common to all ice-contact deposits.
The extreme variation and abrupt changes in grain
size are typical of eskers, crevasse fillings and icemarginal deposits, as is the variation in petrologic composition.
Certain other sedimentary features, however, pro-
vide additional information that tends to discount the icemarginal and crevasse filling hypotheses.
The orientation of the cobbles provides a basis for rejecting the ice-marginal theory.
According to this hypo-
thesis, the cobbles should be aligned perpendicularly to the
trend of the deposit, as the meltwater would flow away from
the ice margin.
Additional evidence for the rejection of
this theory is found in the position of the associated till.
The till, according to the ice-marginal theory, should be
found only on the northeast flank of the deposit.
The till
is found on the northeast and southwest flanks, however,
-27indicating that ice was present on both sides of the deposit during its formation.
The cobble orientation and the contact relationships
of the till to the sand and gravel are not inconsistent
with the crevasse filling hypothesis.
Unless superimposi-
tion of the landform is assumed, the differential in elevation at each end of the feature suggests that the drainage
of the postulated crevasse was to the southeast.
If the
meltwater flowing through the crevasse emerged from the ice
at or near the southeast end of the landform, the sediments
at the southeast end should reflect the emergence of the
stream from its restricted course.
been observed.
No such evidence has
On the contrary, all the evidence that in-
dicates the emergence of the stream from the ice is found
near the northwest end of the landform.
The nature and characteristics of the sediments appear
to be consistent with the eskerine interpretation.
The
orientation of cobbles signifies that meltwater flowed
along the trend of the deposit.
The deltaic sediments at
the northwest end of the landform indicate that the meltwater flowed in that direction.
Perhaps the most important evidence supporting the
eskerine hypothesis is the presence of glacial till on both
sides of the deposit associated with the landform.
In ad-
dition, at every outcrop displaying the contact between the
till and the fluvial materials, the stratified sediments
-
-28extend beneath the till.
This indicates that glacial ice
flanked the landform during its construction.
It is plau-
sible to suggest that the ice may have extended over the deposit, at least during the initial deposition.
This inter-
pretation is further supported by the presence of the till
high up on the flanks of the deposit.
The character of the sediments associated with the
landform and the contact relationships of the till and the
glacio-fluvial materials provide a basis for designating
the landform as an esker.
This conclusion is further sup-
ported by the topographic evidence previously discussed.
CHAPTER IV
RELATIONSHIPS OF THE KANEVILLE ESKER
TO THE GLACIAL HISTORY OF THE AREA
Glacial history --of the area.
The pre-Illinoian Pleis-
tocene history of south-central Kane County is poorly recorded, but it is possible that the region was glaciated
during both Nebraskan and Kansan time.
Illinoian glacial
deposits, while not abundant, have been observed in the
county.
Horberg (1953, p.
43) cites a section originally
described by Powers which indicates that Illinoian ice
passed over the area.
The earliest Wisconsinan deposits recognized in the
area are represented by windblown materials (Horberg, 1953,
P. 43).
The location and configuration of the pre-Bloomington
drift bodies associated with the Green River and Belvidere
ice lobes indicate that the ice which deposited them probably covered Kane County (fig. 10).
However, drift asso-
ciated with these lobes has not been observed in this area.
Deposits of Bloomington till (Horberg, 1953, p. 43)
observed near the Kaneville esker indicate that the glacial
ice which constructed the Bloomington moraine moved over
the area.
Fig. 10.
GLACIAL GEOLOGY I N NORTHEASTERN ILLINOIS
Compiled by George E. Ekblaw from data furnished by the Survey
January 1, 1942
-31The age relationships of drifts deposited between the
time of deposition of the Bloomington moraine and that of
the Marseilles moraine are in question.
In the area of the
Kaneville esker, the problem is further complicated by the
convergence of drift bodies believed to be of different ages
Suter, Bergstrom, et al.
(fig. 10).
the following succession:
moraine, 2.
1.
(1959, p. 39) present
construction of the Elburn
deposition of Gilberts drift, 3.
of the Farm Ridge drift.
deposition
This succession accords with the
relative position of these drift bodies as shown on the accompanying map by Ekblaw (~uter,Bergstrom, et al., 1959,
fig. 5).
The distal margins of these drift bodies may sig-
nify (1) successive stillstands of a retreating glacier,
(2) readvances of an ice front, or (3) a combination of both.
The construction of the Cropsey moraine is believed to
have occurred after the formation of the Bloomington moraine
and prior to the construction of the Fa-rm Ridge moraine
(willman and Payne, 1942, p. 213).
Moreover, the configura-
tion of the Cropsey moraine indicates that the ice responsible for its deposition crossed south-central Kane County.
Comparison of Horbergrs diagrams (1953, pls. 1 and 2) and
Ekblawxs glacial map (Suter, Bergstrom, et al., 1959, fig.
5)
suggests that the Elburn moraine is equivalent to the Cropsey moraine.
The Gilberts drift is believed to have been deposited
sometime after the construction of the Cropsey moraine
-32( ~ e o r g eE. Ekblaw, 1962, personal communication).
Powers
( ~ e i ~ h t o nPowers,
,
-et al., 1931, p. 61) suggests that the
Gilbert~drift may be correlated with the drift of the Farm
Ridge moraine.
If the previous interpretations are correct,
the Gilberts and Farm Ridge drifts are the same age and were
deposited after the Cropsey drift.
These correlations, how-
ever, are based solely on inferences from the literature and
have not been corroborated by field evidence.
Powers
eighton on, Powers, et -*a1
1931, p. 72) found
evidence which indicated that the ice responsible for the
deposition of the Marseilles drift covered the southeast
end of the esker.
There is no indication that any later ad-
vance of the ice reached the area.
However, there may have
been some outwash deposits laid down in the major valleys in
this portion of the county.
of the Kaneville esker.
Stratigraphic position --
The
physical characteristics of the till found on the flanks of
the esker are believed to correspond with Powers1 description of the Gilberts till
p. 33).
eighton on, Powers, et al., 1931,
The position of the esker in relation t-o the line
marking the maximum extent of the Gilberts drift, as shown
.
et a1 , 1959,
on Ekblaw s glacial map ( ~ u t e r ,Bergstrom, fig.
5), further supports this interpretation. In addition,
the landforms in the area of the esker are similar to those
which Powers
eighton on, Powers, et al., 1931, p. 61) des7 -
cribes as exemplary of the Gilberts deposits.
-33Powers
e eight on, Powers,
et s.,
1931,
p.
72) reports
the presence of Marseilles till overlying Gilberts drift
near the southeast end of the landform.
et al., 1959, fig.
(Suter, Bergstrorn, a relationship.
Ekblawls map
5) also suggests such
The present writer, however, fourld only
one exposure suggesting the presence of a till younger than
the Gilberts drift in the area.
In this exposure, located
i n the southeast section, the till was divided by the thin,
discontinuous carbonaceous zone mentioned previously.
The
tills above and below this zone did not differ obviously
from each other.
It is possible that this carbonaceous
material represents organic matter developed on a postGilberts, pre-Marseilles surface.
It is also possible that
this zone represents a surface exposed during a minor oscillation of the ice that deposited the Gilberts drift.
Conclusions.
The till overlying the flanks of the
esker is believed to be the Gilberts till described by
Powers.
Its relationship to the sands and gravels of the
esker indicates that the fluvial materials and the till were
deposited by the same ice sheet,
This ice sheet is believed
to have covered south-central Kane County after the deposition of the Cropsey drift and prior to the deposition of the
Marseilles drift.
It is possible that the ice which con-
structed the Marseilles moraine may have covered the southeast end of the esker.
CHAPTER V
SUMMARY AND CONCLUSIONS
The eskerine theory most plausibly explains the origin
of the Kaneville esker.
The topographic configuration of
the landform presents the most convincing evidence for the
acceptance of this interpretation.
The linear pattern and
irregular crest are typical of eskerine forms. Further support of this interpretation is found in the sediments comprising the landform.
The great variation and abrupt changes
in particle size are characteristic of eskerine sediments.
The alignment of sedimentary particles parallel to the trend
of the landform presents additional evidence in support of
this hypothesis.
The till overlying the flanks of the esker
indicates that glacial ice existed along both sides of the
landform during its formation.
The location and elevation
of the delta are most easily explained by the presence of an
esker stream flowing to the northwest. A small kame and a
short esker-like ridge nearby present additional evidence of
the abundant meltwater necessary to the eskerine interpretation.
The esker was constructed contemporaneously with the
deposition of the Gilberts till.
The southeast part of the
esker may have been covered later by the same ice advance
-35that cons.tructed the Marseilles moraine to the south.
The Kaneville esker and nearby landforms indicate 'chat
the ice which deposited the Gilberts till was characterized
by some degree of stagnation.
Glacial meltwater flowed
through various openings in the disintegrating ice sheet.
Some of the meltwater flowed, possibly upslope under great
hydraulic pressure, along a subglacial channel, now marked
by the Kaneville esker.
At the margin of the ice the melt-
water stream emptied into a pro-glacial lake, resulting in
the formation of a delta at the mouth of the stream.
Further
melting of the ice removed the supporting ice walls from the
sides of the deposit, allowing the materials to assume their
natural angle of repose.
Ax the ice sheet disintegrated,
outlets were uncovered which allowed the body of standing
water to the northwest to drain.
A prominent ridge-like
tract of sand and gravel was left exposed after the disintegration of the ice.
On the basis of the evidence presented,
this landform merits its designation as the Kaneville esker.
REFERENCES CITED
Block, Douglas A., 1960, Sand and gravel resources of Kane
County, Illinois: Illinois Geol Survey Circ. 299,
11 p.
.
Boardman, Don, Odom, I. E., and Wilson, George, 1962, Illinois Acad. Sci. field trip guide leaflet to Wheaton
area: Illinois Geol. Survey Guide Leaflet 62, 13 p.
Flint, Richard F., 1957, Glacial and pleistocene geology:
John Wiley and Sons, Inc., New York, 553 p .
Fryxell, F. M., 1927, The physiography of the region of
Chicago: University of Chicago Press, Chicago, 55 p.
Hopkins, Cyril G., Mosier, J. G., Van Alstine, E., and Garrett, F. W., 1917, Kane County soils: Univ. of Illinois Agr. Experiment Sta. Soil Rpt. 17, 60 p.
Horberg, Leland, 1953, Pleistocene deposits below the Wisconsin drift in northeastern Illinois: Illinois Geol.
Survey Rept. Inv. 165, 61 p.
Krumbein, W. C., and Pettijohn, F. J., 1938, Manual of sedimentary petrography: D. Appleton-Century Co., Inc.,
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Leighton, M. M., Ekblaw, G. E., and Horberg, Leland, 1948,
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, Powers, W. E., MacClintock, Paul, and Workman, L. E.,
1931, Geology and mineral resources of the Barrington,
Elgin, and Geneva quadrangles: Illinois Geol. Survey
unpublished manuscript, 207 p.
Leverett, Frank, 1899, The Illinois glacial lobe:
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U. S.
Suter, Max, Bergstrom,, Robert E., Smith, H. F., Emrich,
Grover H., Walton, W. C., and Larson, T. E., 1959, Preliminary report on ground-water resources of the Chicago region, Illinois: Illinois Geol. Survey and Illinois
Water Survey Cooperative Ground-water Rept. 1, 89 p.
Thwaites, P. T., 1961, Outline of glacial geology:
Bros., Inc., Ann Arbor, Mich., 142 p.
Edwards
Willman, H. B., and Payne, J. N., 1942, Geology and mineral
resources of the Marseilles, Ottawa, and Streator quadrangles: Illinois Geol. Survey Bull. 66, 388 p.