1. Geology, Ecology, andGeology, Ecology, and
Resources of IowaResources of Iowa
By Danielle JannuschBy Danielle Jannusch
2. Welcome to theWelcome to the
Hawkeye StateHawkeye State
• Iowa was a tremendous geologic and
ecologic history. This presentation will
discuss:
– Geologic Feature: Devonian Fossil Gorge
– Ecologic Feature: Iowa Prairie
– Renewable and nonrenewable resources of
Iowa
4. Iowa Geologic historyIowa Geologic history
• The oldest rocks in Iowa are buried deep underground.
• Most of Iowa’s geologic history is written in sedimentary rocks, such as sandstone,
limestone, dolomite and shale, which are over 3,000 feet thick in places. (DNR, 2010)
• Iowa sedimentary rocks originated as layers of loose sediment accumulating in
shallow seas and along coastal and floodplain environments between 74 million years
ago (Cretaceous) and 530 million years ago (Cambrian).
• Over time, this sediment was lithified into rock containing fossil remains of past
animal and plant life.
• Fossiliferous sedimentary rocks are found among the abundant outcrops of
northeastern, eastern, and central Iowa
• Most sedimentary rock exposures in Iowa are found along river valleys, at roadcuts,
and in quarries.
• Since most of our geologic history is buried, most of our knowledge comes from rock
samples brought up to the land surface during the drilling of wells.
• The oldest known formation in Iowa the Otter Creek Mafic Complex (about 2.95 billion
years old), the youngest is the Wisconsinan glacial drift (about 10,000 years old).
(DNR, 2010)
• Additionally, river sediments that are still being deposited today.
5. Iowa StratigraphicIowa Stratigraphic
Column:Column:
This column shows allThis column shows all
the different rock typesthe different rock types
found on the surfacefound on the surface
and in the subsurfaceand in the subsurface
of Iowa terrain Column.of Iowa terrain Column.
This column has beenThis column has been
used to correlate Iowaused to correlate Iowa
rocks with sedimentaryrocks with sedimentary
strata throughout thestrata throughout the
Midwest and theMidwest and the
countrycountry
Source:
http://publicatio
ns.iowa.gov/48
62/1/EM-40.pdf
6. Geologic Feature:Geologic Feature:
Devonian FossilDevonian Fossil
GorgeGorge
• Discovered during the Flood of 1993
when floodwaters from Coralville Lake
came over the spillway eroded away
15 feet of glacial-age sediments to
expose 375-million-year old
fossiliferous bedrock.
• The rocks of the gorge: The
dominant rock type at Devonian fossils
gorge is fossiliferous limestone.
The limestone is rich in crinoids,
corals, stromatoporoids and several
species of brachiopod fossils.
• Limestone is comprised of calcite.
• History of the sediments: These
sediments were deposited during the
Devonian Period about 375 million
years ago, when eastern Iowa was
covered with a shallow sea. The
fossils suggest that this was a reefal
normal marine environment with a
moderate undercurrent (Prior, 1998)
A recreation
of the
Devonian of
Iowa
1993- The
fossil sea is
discovered
after the flood
of 1993
Newly designed
entrance to the
Gorge
http://www.igsb.uiowa.edu/browse/spillway/spillway.htm
7. How has plate tectonics affectedHow has plate tectonics affected
the Gorge?the Gorge?
• Current earthquake activity: Only 13
earthquakes with epicenters in Iowa are
known in historic times. The first known
occurrence was in 1867 near Sidney in
southwest Iowa; the most recent occurrence
was in 2004 near Shenandoah in SW Iowa.
The largest Iowa earthquake (Mercalli
magnitude VI) occurred near Davenport in
southeast Iowa in 1934. (DNR, 2010)
• Activity around the Gorge is rare, but some
of the strata are inclined.
• Looking north toward the Coralville Lake
Spillway some of the limestone strata are
inclined and domed. (DNR, 2010)
• It has been suggested that this inclination
may be the result of irregular settling of the
sedimentary layers when they were still soft,
or the result of much later, broad-scale
warping of rock units across the Midwest.
• Small geologic faults are also exposed here,
with vertically displaced strata and tiny
gouges along the rock faces indicating
movement in the geologic past (about 310
million years ago) (Prior, 1998)
•http://www.igsb.uiowa.edu/Browse/earthqua/iowa_quakes.htm
8. Glacial and Surficial Processes andGlacial and Surficial Processes and
their impact on Iowatheir impact on Iowa
• Glacial processes are responsible for
many of the geologic features
throughout the state.
• The “lake district” area of northern
Iowa is dominated by natural lakes
and bogs, among irregularly shaped
hills, and in the boulders- all evidence
of glacial activity (Anderson and
Prior, 2010)
• This region is called the "Des Moines
Lobe," Its name refers to the location
of Iowa's capital city at the
southernmost limit of this former ice
mass. (Harr et al, 2010)
• The geologically fresh deposits of the
Des Moines Lobe still display the
special landscape shapes that result
from direct contact with melting and
disintegrating glacial ice. (Anderson
and Prior, 2010)
• The Flood of 1993 was the defining
erosional process that uncovered
Devonian Fossil Gorge. Moderate
wind and water erosion is responsible
for the current weathering of the
Gorge. Acid rain leads to chemical
weathering of the Gorge’s limestone.
http://www.igsb.uiowa.edu/Bro
wse/glatrail/glatrail.htm
10. Ecological feature: Iowa PrairieEcological feature: Iowa Prairie
• Iowa had the largest percentage of its area covered by
tallgrass prairie - 30 million acres before European
settlement (IAN, 1998)
• Now, only 0.01% of the original prairie is left
• Iowa prairie originated nine to ten thousand years ago,
following the retreat of Iowa’s most recent glaciers.
(IAN,1998)
– Prairies formed in much of north and central Iowa due to warm,
dry climatic conditions
• Once established, prairie plants held their ground. The
dense roots of prairie plants did not allow invading trees
and shrubs to grow. (IAN, 1998)
11. Plants and Animals in the IowaPlants and Animals in the Iowa
Prairie (IAN, 1998)Prairie (IAN, 1998)
• Plants (Autotrophs):
– Big bluestem
– Grasses: Indian grass, Code
grass, Switch grass
– Wildflowers: Compass plant,
black-eyed Susan, lead plants,
prairie coneflower
• Wildlife (Heterotrophs):
– Bison, elk, antelope, wolves,
prairie dogs, red fox, coyote,
moles, shrew
– Birds: meadowlark, red-tailed
hawk
– Insects: spittelbugs, ants,
grasshoppers
– Reptiles and amphibians:
ornate box turtle, western
hognoose snakehttp://www.nps.gov/archive/wica/images/Big_Blue_Stem.jpg
http://www.nps.gov/wica/naturescience/images/Prairie-Coneflower.jpg
12. Food webFood web
in an Iowain an Iowa
PrairiePrairie
(arrows in the(arrows in the
direction of energydirection of energy
flow)flow)
http://www.nps.g
ov/archive/wica/i
mages/Big_Blue
_Stem.jpg
http://www.natur
ehills.com/image
s/productImages
/black_eyed_sus
an_goldstrum_1.
jpg
http://www.nps.g
ov/wica/naturesc
ience/images/Pr
airie-
Coneflower.jpg
13. Endangered/Exploited species inEndangered/Exploited species in
IowaIowa
• In Iowa, Chapter 481B of
the Code of Iowa protects
endangered species
• Violations of the
provisions of Chapter
481B for threatened or
endangered species are
misdemeanors
punishable by a fine of up
to $100.
• Complete list:
http://www.iowadnr.gov/w
ildlife/files/wildinfo.html
http://www.iowadnr.gov/other/threatened.html
Iowa
Pleistocene
land snail
Higgins eye
pearly mussel
Osprey
Western
prairie fringed
orchid
14. Local biodiversityLocal biodiversity
• Iowa’s landscape and biodiversity have changed
drastically over the past 150 years and the
prairie has been destroyed (IAN, 1998)
• Alteration and redirection of many Iowa streams
has caused a decrease in the marshland and
marshland communities throughout the state
• Pollution and land clearing are the major forces
that have changed Iowa’s biodiversity (IAN,
1998)
16. Mineral/ Rock ResourcesMineral/ Rock Resources
• Most of the mineral
resources in Iowa are
used for construction and
building materials
Examples are:
– Clay and shale
– Crushed limestone
– Gypsum
– Cement
– Sand and gravel
• These minerals and rocks
are extracted from
quarries throughout the
state
http://www.igsb.uiowa.edu/Browse/gypsum/gypsum.htm
17. NonrenewableNonrenewable
resources found inresources found in
Iowa: CoalIowa: Coal
• Small quantities of coal were first mined in
the 1840's near Fort Des Moines and along
the lower Des Moines River (Coal, 2002)
• In 1854 the Rock Island Railroad reached
the Mississippi River, and by 1860, 500
miles of track existed in Iowa. By 1876 the
North Western Railroad reached Council
Bluffs, and Iowa was the leading coal
producer west of the Mississippi and fifth in
the U.S. (Coal, 2002)
• By 1914 the state's rail network included
9,216 miles of track, and by 1918 annual
coal production in Iowa peaked at 9.3 million
tons.
• Production declined thereafter and the
industry shifted from underground to surface
mining operations. (Coal, 2002)
• By 1920, almost all Iowa coal mines had
been shut down, in favor of mining the
cleaner coal in Illinois. Mining operations
shifted from coal to gypsum and limestone
18. Iowa’s renewable resourcesIowa’s renewable resources
• The two major renewable energy sources
harvested in Iowa are wind energy and
bioenergy and biofuels
• Wind energy
– Iowa is the second largest producer of wind
energy in the US, just behind Texas. (IEC,
2010)
– Iowa has 3,670 MW of installed wind power
which is enough to power approximately
1,125,000 homes (IEC, 2010)
– Wind energy is producing jobs in Iowa
• Biomass/bioenergy
– Iowa has 31 ethanol plants in operation,
producing approximately 2.54 billion gallons
per year. (bottom picture)
– Iowa leads the nation in biofuels output
accounting for 26 percent of U.S. ethanol and
12 percent of biodiesel production capacity
(IARFA, 2010)
– Ethanol lowers harmful carbon monoxide
(CO) emissions by 30 percent and reduced
carbon dioxide (CO2) emissions by 27
percent. (IARFA, 2010)
– 11 landfills in Iowa that are candidates for
electric generation (Bird et. al, 2005)
http://iowa.com/wp-content/uploads/2008/12/ilive-weather.jpg
19. Human impact on our resourcesHuman impact on our resources
• As humans it is our responsibility to conserve
nonrenewable natural resources and replace
nonrenewable resources with cleaner, more
environmentally friendly renewable resources
• Going green can mean and increase in the
number of jobs. In Iowa alone, ethanol and
biodiesel production supported 83,000 jobs in
2008 (IARFA, 2010)
• Relying on alternate energy sources can cut our
dependence on foreign oil , since wind energy
and biofuels are produced right here in Iowa
20. ReferencesReferences
• (2004) Stratigraphic Column of Iowa, 2004. Natural Resources, Department of.
• Devonian Fossil Gorge photo: http://www.mvr.usace.army.mil/coralville/devonian_fossil_gorge.htm
• Flood of 1993 photo: http://www.igsb.uiowa.edu/browse/flood93/flood93.htm
• Gypsum photo: http://www.igsb.uiowa.edu/Browse/gypsum/gypsum.htm
• (2002) Coal Geology of Iowa. 2002 Keystone Coal Industry Manual ®
• Bedrock Geology map: http://www.igsb.uiowa.edu/browse/geoiowa/geoiowa.htm
• (1995) Iowa Biodiversity. Iowa Association of naturalists
• Iowa prairie map: http://www.igsb.uiowa.edu/portrait/3change/Change.htm
• Bird, L. et. al (2005) Iowa Renewable Resource Assessment
• Anderson, R.R. and Prior, J.C. (2010). Glacial Boulders in Iowa. Retrieved March 22, 2010 from
http://www.igsb.uiowa.edu/Browse/boulders/boulders.htm
• Harr, D.C. et. al (2010). Glacial Landmarks trail: Iowa’s Heritage of Ice. Retrieved March 22, 2010 from
http://www.igsb.uiowa.edu/Browse/glatrail/glatrail.htm
• Iowa Department of Natural Resources (DNR). (2010). General Geology. Retrieved March 23, 2010 from
http://www.igsb.uiowa.edu/service/geology.htm
• Prior, J.C. (1998) Devonian Fossil Gorge. Iowa Department of Natural resources. Retrieved March 20, 2010 from
http://www.igsb.uiowa.edu/browse/spillway/spillway.htm
• Iowa earthquake map: http://www.igsb.uiowa.edu/Browse/earthqua/iowa_quakes.htm
• Iowa Energy Center (IEC) (2010). Wind Energy in Iowa. Retrieved March 24, 2010 from http://www.energy.iastate.edu/renewable/wind/
• Iowa Wind Farm picture: http://iowa.com/wp-content/uploads/2008/12/ilive-weather.jpg
• Big Bluestem picture: http://www.nps.gov/archive/wica/images/Big_Blue_Stem.jpg
• Prairie cone flower picture: http://www.nps.gov/wica/naturescience/images/Prairie-Coneflower.jpg
• Black-eyed Susan picture: http://www.naturehills.com/images/productImages/black_eyed_susan_goldstrum_1.jpg
• Iowa Association of Naturalists (IAN) (1998). Iowa Prairies. Iowa Biological series. Iowa Association of Naturalists. (IAN-203)
• Mole picture: http://www.allstateanimalcontrol.com/images/large%20images/moleBig.jpg
• Iowa Renewable Fuel association (IARFA)(2010) . Ethanol Facts. Retrieved March 26, 20910 from
http://www.iowarfa.org/ethanol_facts.php
