“Mid-Continental Geology,” by William Gilliland.


Well, I’ve always been a generalist. I started
working for the Highway Commission in the summers and then
worked for the Kansas Highway Commission after I graduated. That’s
where I met Dick when we initially formed the Kansas City-Omaha
section of the Association of Engineering Geologists back
about 45 years ago, and then I worked in research for the Highway
Commission. I got paid to be curious. I inspected dams for the
Department of Agriculture. I went out and worked in the
oil and gas industry for a short time, got back on the State working
in water rights, and my hobby has been adjunct professor. This
is my 29th year at Washburn and I taught at Wichita State and
Pratt Community College, so the students make me stay current.
From some of the evidence of looking at the quality of coals
in eastern Kansas, it appears that approximately one-half mile of
material has been removed off of eastern Kansas, so it had been
deposited possibly up through Cretaceous times and then with
the uplift essentially one-half a mile has been eroded away and once
that material is eroded away it’s carried downstream and
been emptied out into the Gulf of Mexico. At one time the Gulf of Mexico
had an embayment that extended as far north as Cairo, Illinois.
The material that’s eroded off the midcontinent is filled
in that embayment all the way down to the present Gulf Coast.
So there’s been a lot more of Kansas and Missouri here in the
past but it’s gone so we have to sort of use the best evidence we
have from other places that correlate back to Kansas and Missouri
to get an idea of what went on during this time period, so
now, if some of you have some questions. I’ve got one. As you drive around Kansas
City/Topeka, this general area around this general region, what
are the top geological sites that we should be aware of
or the most valuable geological sites? Well, some of the nice ones were exposed along
Interstate 70. Here in the Kansas City area you have most
of the rock layers of the Kansas City formation or group I should
say, Kansas City group, exposed. Those layers do dip to the
west and further out in western Kansas in some of the deep oil
fields they do produce oil and gas out of those zones, and perhaps
you’ve noticed some of the black shales that have been deposited
around. They sort of weather out at the surface, sort of dark
gray in color and almost break into paper-thin layers. Well
these are high organic shales. They didn’t have enough organic
material in them to become coals, but out of the carbon that was
in those layers when they’re buried heat and pressure we cook
out the carbon and form oil and gas, so they are some of the producing
horizon or source rock horizons as you go further west. Also,
some people are concerned about the black shales. Most of
them have a rather high radioactive content. I knew one geologist
with Kansas Geological Survey. It turned out he was excavating
a site for a new house he was building in Lawrence and
actually excavated into one of the black shales. Of course, everyone
was concerned now, are you going to get radioactive products
out of them, but unfortunately, well I should say fortunately
those shales are so tight that the radioactive gases and daughter
products can’t migrate out of them. They’re trapped within
shales. So you have more problems with things like radon coming
out of some of the gravels with breakdown of uranium. So really
the black shales you don’t have to worry that much about
here, but in western Kansas they’re great markers in the oil
and gas industry for running radioactive logs and interpreting
the stratum out there. In the Manhattan area, the Tuttle Creek Spillway—it
was badly eroded in the ’93 flood with the massive
amount of water that went through that, but the work with the Kansas
Geological Survey and paleontologists world-wide they have determined
that the boundary between two (pardon me), boundary
between two periods occurs in the spillway at Tuttle Creek in
the Howell limestone and this limestone is actually the boundary
between the Pennsylvania and Permian periods, and now
with correlation with the layers in the Perm Basin in Russia, Tuttle
Creek Spillway has been designated as the stratotype for the
Pennsylvania and Permian boundary for the entire North America.
Now that gets geologists excited but not too many other
people, but you can go up in the spillway at Tuttle Creek and collect
some fossils that are loose on the surface or some of the rocks
that are loose. They don’t allow you to dig in the spillway.
Dick mentioned the ice over Kansas City area was probably 400
or 500 feet thick. At Topeka, we just barely had the ice push across
the Kansas River and was maybe 100 or 200 feet thick, but if
you get back up to the northeast corner of Kansas and right where
the states pretty well come together up there, probably the
continental glacier was 1,000 feet thick. As you go on up to the center
of the continental ice up in Canada, there your thickness
was probably around 10,000 feet thick. So the ice basically
filled up this big pile that acts like mountain ranges do
today, actually directed the weather around itself and drew
in moisture and leashed it out to continually build it up
until the end of the Ice Ages. How can you estimate how thick it was in different
areas like that? What is it you look at that tells you
that? In part, some of the deformation in the shales
and limestones and how much pressure it would have taken to deform
those layers. Also, Hudson Bay is the largest continental
sea in North America and it’s still there right now because the
crust hasn’t completely rebounded from being depressed
by the great ice cap that was over that area and as it rebounds
probably the Hudson Bay will eventually be dry, and also the area
to the north side of the Great Lakes is rising up faster with
rebound than on the south side so we are actually spilling the
Great Lakes toward their southern shorelines and eventually maybe
we’ll get the Lake Michigan draining back into the Mississippi
basin like it used to. Is it going to take the silver carp with it? Actually, the Himalaya Mountains distort the
movement of the air currents around the Northern Hemisphere. Well,
when you add 10,000 feet of glaciers it also did the same
sort of distortion and that brought moist Pacific moisture down
in across the southwestern United States and that was dumped
out there and it fed all the pluvial lakes that are in the
desert basins that we see today. Now, that much weight of ice tends
to grind up the rocks at the bottom and quite often literally
reduces the rocks to flour-sized material. So if you see a white
stream coming out of a glacier, this is carrying out that glacial
flour and then as it goes out away from the glacier the channels
get filled up, the channels move back and forth over an alluvial
surface, and then periods where it’ll dry up and the winds
will pick it up and blow it up out of the river valleys and up onto
the surfaces around it. So these vertical loess bluffs you get
right here in the Kansas City area, it used to be the Highway
Commission tried to stand those up straight because they’d stand
up that way and they wouldn’t erode off, but then with the newer
ideas about wanting to have vegetation on the slopes and making
them all nice and pretty and covered with vegetation, which
as a geologist I think that isn’t the right idea. Let’s have
the nice rocks out there to see them. But the loess would build up
layer by layer and it has a vertical structure that allows water
to migrate through it and so it’ll stand up, but once you lay
it back then you notice there’s an awful lot of erosion to those
slopes. You have to get them vegetated to preserve them then and the
loess makes fantastic agricultural land. The loess areas
out in western Kansas—these are our productive fields out
there now, we all, the irrigation water to them. And also, finer
material was blown up and clays were carried further away than the
silt-size loess, so as you get away from the loess areas than
the soil starts getting tight because you have clays out in those
areas and it makes a tighter soil that you have to deal with. Yes
sir. I see the Highway Department has cut through
rocky areas and so we can see the strata through the ages. Uh-huh. OK. And I also see the, like a river bottom,
like the Missouri River bottom, the bluffs are 200 or 300 feet
high, and is that naturally water erosion? Yes it is. The streams removing the material.
Huh. When the glacial periods are in at their maximum,
this last glacial period probably lowered sea level
about 450 feet because that water was taken out of the oceans and
locked up on the continents. So that allowed the streams to
cut down to a lower base level. So right here under the Missouri
River, under the Kansas River, those streams cut down very
deep valleys under the present valleys to match sea level that was
450 feet lower. Then as sea level rose that led to more sediments
filling in those deep cuts and brining the level back up to
above what we see today, and we’re in an erosional period
for the streams to be cutting back down into their alluvial valleys.
I believe under one of the bridges on the, I can’t remember
which highway it is, had about 170 feet of alluvium underneath
the surface before they started building the bridge. So I see this strata thousands and thousands
of years and that’s pretty comprehensible that it grew up or was
deposited, and then there are also rocks on the surface which
just seem to be out of place, and could you describe some of those
rocks or how they got there. Well, they call those erratics, and most of
them in this swath of Missouri and Kansas were brought in by the
glaciers. That’s why you can have the giant boulders that were
carried along in the ice and in some cases those boulders were
locked up at the bottom of the ice and they actually left gouges in
the bedrock, can be traced to some of the giant boulders that
were dropped by the ice and preserved at the present time. And humans,
particularly like the pink quartzite boulders so future geologists
are going to have a hard time interpreting the edge of
the ice field because humans are taking this stuff out and using
it for decorative purposes and hauling it all over the place.
So that and these little asphalt seams and artificial conglomerate
seams that run all over the place we call roads. Just think
what they’re going to do to the poor geologists in a few thousands
of years trying to interpret those deposits. I have lots of questions. (Laughs). How about
back in Pangaea, was it when all the continents were together
in one land mass? Yes, that was the last supercontinent. Supercontinent, and were changes being made
then or formations occurring then that the continents broke apart
and they were all carried away (Uh-huh) that were what we see
today is something that happened maybe back when it was all together. Record in rock and continents are nice. They
keep the things above sea level where it’s easier for us
to study them, and really no place on the sea floor itself is
the surface more than 250 million years in age because all the sea
floors older than that have already been recycled. Now occasionally
sea floors are trapped within the continents so the continents
are lighter, they float above the heavier mantle and they don’t
sink and get recycled. So this is how we can study these
older rocks that are trapped here on the continent. Now, how old
do you think southern Kansas and southern Missouri are
as far as compared to the age of the earth? The granites that underlie
these areas were developed on the edge of what became
North America continent, about 1.4 to 1.5 billion years
before the present, and then they got eroded off, they’ve been covered
over, had more deposits laid down on top of them but preserved
and we can drill through and study, but down in Woodson and
Wilson counties in Kansas we had volcanos back about 90 million
years ago during Cretaceous times that erupted so violently
they absolutely ripped some of those primordial continental granites
that formed North America and brought those up within the magma
so we can actually find some of this ancient bedrock granite
in boulders that are included in those volcanics down in those
areas, and we had some 4-H geology kids down there just a little
over a week ago that on a field trip where they had actually collected
native volcanic metamorphic rocks. This is a follow-up question on the erratics.
I’ve never noticed that as a casual person, what would you see,
what would you be looking for if you’re in a glaciated area,
like, I mean north of the river somewhere. Is there someplace where
you would see that? Yes. Quite often you’ll see from gravel-size
up to boulder-size these generally pink quartzites. They were
river sands that had been metamorphosed into the quartzites and
if they have more iron in them they may be purple. If they have less
oxidized iron within them they may be as pale as white,
but they’re, quartzite is very resistant to breakage and grinding
so it would actually last better than the other type rocks around
it so it gets left behind as a residual, particularly as weather
removes the soil and gravels around it. Also, sometimes you
can find sort of grayish-green rocks and these are referred
to as greenstones, and these were ocean pillow lavas that were formed
3.8/3.5 billion years ago up in what’s now Canada, the formation
of that area of Canada, and the glaciers also ripped those
up and brought them down. So now you can find they call them a
greenstone and generally if you break them open inside you
see the black basalt that hasn’t been altered by weather to give
it that green shade. Yeah, usually it’s unsorted. It’s all
kinds of sizes together and those quartzite boulders come up from
the corner, northeast corner of Iowa up into Minnesota and up into
the Dakotas. A few years ago my wife and I went out to
Cheyenne Bottoms, very surprised to find a huge wetlands in the middle
of Kansas. Could you talk a little bit about the geology of
Cheyenne Bottoms? That’s been argued a great deal (laughs)
and apparently the Cheyenne Bottoms is in a structural sink,
a declined area, and the most likely explanation for this is more
soluble materials have been eroded out from underneath that
area by ground water and that’s allowed this basin to form and
develop, and it probably removed halite or salt that was deposited
in the formations below that. But the strange part
about it is the structure of Cheyenne Bottoms itself. Actually,
it extends and includes much older rocks than the rocks that
had the evaporites in them. So we never completely answered the
question of how that formed. Had some, a lot of interesting
hypotheses but as the elderly lady in Missouri said when she
was calling her husband “hypothesis” and the pastor said,
“Your husband’s George. Why do you call him hypothesis?” “Well,
he never works”. So hypotheses are ideas that don’t have all
the information to call them a theory. How many of you are interested
in Indian artifacts? The glacial material has also brought
down catlinite and catlinite is Indian pipestone and some
of the tribes up in Minnesota and Iowa in there had the rights
to go into the state park up there and still quarry the catlinite
for their ceremonial purposes, but you can actually find catlinite
within some of the glacial tills. It looks a lot like what people
call jasper but it’s soft enough that you can scratch it
with a steel blade or a knife or a nail, but glaciers are great. They’ve
brought all this outstandingly strange geology into this
area for us to be able to study. And did the glaciers didn’t just like come
down from the north, they started in different places and spread
out from there? Yeah, depending on which way the ice would
move. Some of it that the ice load might move out to the west and
then circle around and come back to the east from that direction,
or within the glacial material across the northern part
of north, across the United States, and particularly they found
diamonds in the glacial material, very scattered, but by tracing
them back and looking for minerals that are related to diamonds
in the pipes they’re able to uncover the pipes up in
Canada and instead of a volcano standing up, those soft kimberlite
pipes were eroded out by the glaciers, so here you have all these
lakes up in the wilderness area that overly these glacial,
these diamond-rich, kimberlite pipes. So really they’re going
in and they’re mining under these lakes for the diamond production. Where could we find a diamond, you say? (Laughs). You can also go down in Arkansas
and try to find diamonds down there at the Crater of Diamonds
State Park. You go in and pay your fee and they have this field
out there that they plow up occasionally that is the weathered
kimberlite material and you can go out and dig for and see and
try to find diamonds. Pat and I, we found sunburns while we were
there. They’re very rare but about the time we were leaving they
did blow the siren saying someone had brought a diamond in to
be identified in the headquarters, the museum area, and you get
to keep them. Yeah, there’s clays most everywhere. Clays are
a family of minerals and then we also use clay as a term for very
small size particles, but the clays are actually related
to the mineral feldspar that you find in granites and a lot
of the other igneous rocks. As those weather and break down they
change the structure. They incorporate water into the
structures and you start getting the clay minerals formed and
quite often the clays are very platy and particularly kaolinite
is one of these that the structures are fairly strong horizontally
but then they’re weak between and they take in an awful lot
of water. Oh. That could give you your shrinking and swelling
clays that you may have trying to raise gardens in or have problems
with your house with the clays moving. Some of the real good
clays—normally they don’t settle out until the water is real,
real, has lost all its forward motion, so it has to be still water
for the particles to very slowly settle out because they’re so
small, and this might happen in an ocean basin at the margin of
the ocean where clay is laid down that later becomes shales and you
can also get clay deposits in lakes, and I do know of a case
years ago back in the 50s. There was a little tussle between the
U.S. and France so they started raising tariffs on things and
something they decided they could put a big tariff on but it wouldn’t
mean much, it would be more figurative-type thing, was clays
for artistic use. Southwestern College down at Winfield ran
out of clay and they found out the tariff they would have to pay
on it would be about ten times the cost of the clay they normally
imported from France. So the Art Department talked with
one of the geologists that was teaching at that time and he said,
“You know, I vaguely recall some mention of clay pits here on the
property”. So they went out on the backside or the west, east
side of the campus and found some of these old clay pits and these
weathered Permian shales actually were better quality clay than
what they’d been importing from France. Weathered Permian shale? Permian shale. Does
that mean that the, if I have this right, the swamp when
Canada when the area was a swamp, then they became shale, and then
later that weathered into clay? Well, these clays were laid down at the margin
of the ocean when it was hot, dry, and evaporated sea water.
Oh. And these particular clays were laid down at the margin
of that, compressed into shale, but now that they’ve come back
to the surface and eroded, as they’re eroding out the quality
of the clay was very good for artistic uses. They have been doing
vertical fracking in the oil and gas industry by going down
where the drill hole went straight through the layers and then
they would frack those to allow the oil and gas to come in easier.
But the big change now, well it started that sort of fracking
in Kansas in 1948, but this new change is where they’ve gone in
and they developed technology to steer the drilling in such a
way that they can go vertically, then kick over in a curve and
actually go horizontally in thinner layers that hold oil
and gas. Then they go in and put those under pressure that fractures
the rocks up, allows the oil and gas to move in, and they
put in sand to help prop the stuff up, but the life of those type
of oil wells is shorter compared to most vertical wells because
you’re draining more of the formation in a short period of
time instead of having it slowly migrate into a vertical-producing
well. Now what they’re saying with the fluids from that—some
of them are nasty. For the most part we don’t have trouble
in Kansas and Missouri with that because it’s being done deep enough.
Back east in shallower areas they did have some problems
with people who didn’t obey the rules. This led to some
of the contamination problems. Now, the fracking causing earthquakes.
It’s unlikely to do it in oil field fracking. It’s the
fluids that get injected, the increased amount of salt water
and other contaminated fluids they’re pushing back
in because they’re producing so much more. Now this raises the
hydraulic pressure down underneath there. If there’s already
a fault or something it tends to lubricate it and make it more
likely to move. So fracking itself normally won’t be an effect
of that in the midcontinent region, but from those fluids
that they’re trying to get rid of down the disposal wells. This is
just (recording cuts off here), particularly saltwater and, pardon
me? Do they bring it from the sea? How does it
get to the midcontinent? Well, that’s trapped in the rocks down there.
Oh. It gets produced along with the oil and gas. Oh. As
that comes up you separate it out and you have the oil and gas
you sell and then you have to do something with the saltwater.
Yeah, they pump it down what they call a, they either let it
flow freely down disposal wells or if they’ve got a whole
lot of it and they’re in a big hurry then they pump it down. Now the
pumping increases the pressure and causes these problems we
think are leading to the earthquakes. Do you think that they’re going to have
any earthquakes where they’re doing the fracking, the most fracking
today? Well, that’s in Oklahoma right now. It is?
They jumped from what three earthquakes, three or four earthquakes
over a 4.0 Richter magnitude in about ten years, now
they’re talking about two or three hundred a year. Two to three
hundred. (Comment in back, inaudible). Yeah. Between cigarette smoking and cancer? Yes.
Yeah. The oil industry (smoking gun or what) has hired the
same lawyers from the tobacco industry. Would you like to make some comments about
the fossils on the top? Yeah. This one, I drool over that. This is
one of the saber-tooth cats. I am not sure if this is
the most recent one. I hate to handle it in case I drop it, but
saber-tooth varieties of cats have come and gone over the ages.
They even have some of the predecessor creatures to the cats that
developed this type of saber and basically these aren’t like our
modern biting cats that have smaller stronger teeth that they’re
able to take on and bite into. They don’t like to but they can bite
into bone and do quite a bit of damage that way. Like the lions,
they don’t try to bite through somebody’s spine. That’s
liable to wipe out their teeth, so they go in and try to go for
the throat to choke them down or cause loss of blood. Now the
saber-tooth cats, generally they have serrations along the backside
of the saber and it’s also more knife-like. So they’re
more of an animal that would go in and take down their prey by attacking
and ripping into the flanks or the belly of their prey
and taking them down by loss of blood and shock. There have been
cases of Smilodon in which they’ve, that’s one of the most
recent of the saber-tooth cats, that they find an elderly animal’s
fossil that the broken sabers have possibly healed somewhat and been
rounded off by use, so we think they lived in prides like lions
do and the other members of the pride would be bringing in
prey and the elder statesman shall we say was able to survive
that way. There’s also the dirt-toothed cats. They have a smaller
knife-like tooth and they again, they’re more of a flank
and belly attacker than they are trying to go for the front end, the
throat, or areas where there might be large bones. And this
particular one, I’ve tried to collect some of these out in western
Kansas. This is a cephalopod and you’re probably aware of
the cephalopods today that we have like the squids, the octopus
(octopi), and these would have these fancy shells this way. The
only curl, the only shell coiled cephalopod we have today are
the nautilus, and you see the nice nautilus shell they get from
the Pacific or the Indian Ocean that they use for decorative
purposes. This character would start coiled out, then they
would start straightening out and then start curling back,
and I believe these are scapolites. So here the animal would
be up here with these squid-like tentacles and these water
jet to move around, and they think maybe this is a modification
to get the center of gravity closer in so they’re more maneuverable.
Some of the straight cephalopods may find evidence of
some of them up to 18 feet long. So if they’re that straight it’s
difficult to steer. Ammonites? Yes, that’s, the first ones of those were
the nautilus that had the most simple shell and they’re the ones
that have straight petitions between the, where the animals have
grown and moved forward, built more shell and then sealed
off the back. But they also have a sifuncal, a tube that goes all
the way back to this initial chamber that they built back here
and they can use that to adjust their buoyancy by moving saltwater
back into the different segments, moving gas in and out,
and they can change their balance with their nice even coil, then
the center of gravity is real close into their tentacles
and it makes them much more agile, being able to basically turn on
a dime, and then with the tentacles some evidence of some of the
ancient cephalopods that they may have had 20-30 foot tentacles.
Modern ones, of course, have much shorter ones until you get
into the big squids. Thank you so very, very much.