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Bobbie Rice
Professor Keeler
Geography 219
Paper: South Dakota, Land of Infinite Variety
South Dakota: Land of Infinite Variety
South Dakota has long been known for its beauty and majestic landforms. Within the
borders of this state a person can find mountains, rolling hills, glacier lakes, prairie, sand dunes,
buttes, canyons, and wetlands just to name a few. It is because of this that the state has become
known has the land of infinite variety. It is easy to appreciate all the beautiful landforms that
South Dakota has to offer now in the present day, but how did it get this way, and what was it
like before? I would like to take a look into South Dakotas great landforms and regions in the
present day, and also explore a brief history of what made them what they are.
South Dakota Geologic History Time Periods:
Precambrian Era -4 billion years ago to 540 million years ago
This time period took place over 540 million years ago all the way up to 4 billion years ago and
is the oldest time period in the geologic timescale. According to Geology About, the oldest rocks
found in South Dakota occurred during the Precambrian period. These rocks were composed of
granite and metamorphic rocks and are found in two different locations in South Dakota, which
are the Black Hills and a small area in the eastern part of the State. According to New World
Encyclopedia, the core of the Black Hills is made of granite and dates back to 1.8 billion years
ago. Although the core of the Black Hills is very old New World Encyclopedia says that there
are two locations that have older rock that dates between 2.2 to 2.8 billion years old, which is Elk
Creek Granite in the northern hills, and Bear Mountain Complex located in the west central hills.
Paleozoic Era -250 to 540 million
years ago According to Black Hills
Visitor From around the end of the
Precambrian time period all through the
Paleozoic era South Dakota experienced its
first sea which covered areas of the western
part of the state first. Seas came and
retreated many times over west South
Dakota leaving layers of rock behind each
time.
Cambrian Period- 485 to 540 million
years ago- During the Cambrian period
South Dakota was mostly eroded and had an
overall flat surface.
University of Tennessee Geologic Time Scale Chart
Mesozoic Era -71 to 250 million years
ago
Jurassic Period- 144 to 201 million years ago-During the Jurassic period low seas again
covered the western part of South Dakota.
Cretaceous Period- 143 to 71 million years ago- In the Cretaceous Period, which occurred
during the Mesozoic Era, all of South Dakota was completely covered with ocean. According to
Northern Education, during the cretaceous period western South Dakota obtained shale,
sandstones, and lime stones. Also deposited were thick layers of marine sediments. These
sedimentary rocks were deposited over 65 million years ago in a very large inland sea that
covered most of this state. According to Geology About, During the Cretaceous period the ocean
was so high at this point in time that this part of the continent was flooded with a great sea way.
The end of the Mesozoic era is the last time seas covered South Dakota. The end of the Mesozoic
era is also when the Black Hills of South Dakota were being created beginning around 70 million
years ago. According to Black Hills Visitor overall more than 6,000 feet of rock layers have been
removed from the Black Hills over time due to erosion.
Cenozoic Era -70 million years ago to Present
During the beginning of the Cenozoic Era starting around 70 million years ago until about 40
million years ago the Black Hills were being created in what is known as the Laramide Orogeny.
According to MSU Education the Laramide Orogeny is a major tectonic event that was
responsible for the mountain building of the Rocky Mountains and the Black Hills of South
Dakota.
Oligocene Epoch- 23 to 33 million years ago- Streams in Black Hills area could no longer
carry the amount of sediment in them . Deposits began to cover the area around the Black Hills
until it worked its way up covering a good portion of the hills themselves. During this time less
than 2,000 feet of the Black Hills might have actually been above ground. A change in climate or
further uplift caused the erosion process to that revealed the hills to what they are today.
Pleistocene Epoch- 2 million years ago- Ice Age caused reoccurring glaciers that covered
eastern South Dakota off and on. After the glaciers melted they left behind glacial drift and
glacial lakes.
Holocene Epoch- 10,000 years ago to present- Holocene is the most current geologic epoch,
and includes things that have occurred in the last 10,000 years up to the present time. The last
glaciation period in South Dakota was the Wisconsin Glaciation period that ended 10,000 years
ago.
South Dakota Today
There are many ways South Dakota could be divided into regions or provinces. Some
sources break South Dakota into two halves which would be East River and West River
seperated by the Missouri River that divides the state. Others might break it into three sections,
The Central Lowlands, The Great Plains and The Black Hills. According to New World
Encyclopedia South Dakota is made up of four different land regions. These regions are the Drift
Prairie, The Dissected Plains, The Great Plains, and The Black Hills. These four regions are the
ones I will use to divide the state into smaller areas.
Drift Prairie- The Drift Prairie region takes up the majority of eastern South Dakota. This
region of South Dakota contains glacial lakes, low hills, grasslands, lowlands, and wetlands. This
land region can be broken down into 3 smaller sub regions, which are The Minnesota River
Valley, The Coteau Des Prairies, and The James River Basin. Reoccurring glaciers from the last
Ice Age carved and shaped these regions, and most of northeastern South Dakota into what it is
today. According to Northern Education this process of Glaciation in South Dakota began in the
Pleistocene Epoch around 1.5 million years ago. Glaciers moved across the eastern part of South
Dakota several times causing erosion, moraines, glacial drift, lakes, and other land features that
make up the eastern part of the state. The last glaciers in South Dakota retreated around 10,000
years ago in what is known as the Wisconsin Glaciation period.
The Minnesota River Valley is located in the far north eastern part of South Dakota. This
areas land characteristics are the result of an ancient river that flattened it out and glaciation
which eroded and carved it. According to Princeton Education, during the Wisconsin Glaciation
period this area of South Dakota was a drainage system for the largest glacial lake to occupy
North America, Lake Agassiz. The Minnesota River was just one of the numerous drainages for
this massive ancient lake. According to Geography of South Dakota, Lake Agassiz shaped the
land of the Minnesota River Valley by leaving a series of low beach ridges behind, and also a
narrow trench which is now occupied by two main lakes, which are Big Stone Lake and Lake
Traverse. The Minnesota River Valley is covered extensively with water from these two lakes
with the remainder of its surface lowland with two main moraines, which are the Gary Altamont
and Big Stone moraines.
The Coteau Des Prairies is found bordering the west of the Minnesota River Valley. This
land area is known for its beautiful grassy low hills and many glacier lakes. According to
Netstate Coteau Des Prairies meaning prairie hills, got its name from French fur traders. This
200 mile long flat iron shaped plateau is bordered by the Minnesota River Valley on the east and
the James River Basin on the west. The main drainage system for Coteau Des Prairies is the Big
Sioux River. According to Geography of South Dakota most of the glacial lakes in this area can
be found to the west of the Big Sioux River due to drainage differences during the melting of the
last glaciers. Geography of South Dakota also states it is believed that Coteau Des Prairies exists
due to ancient stream valleys that gave the plateau its shape.
The James River Basin is the area found in between Coteau Des Prairies and Coteau Du
Missouri. The area extends along The James River, which is the main drainage system for The
James River Basin. The James River Basin is characterized by highly eroded lowland, marshes,
wetlands and glacial lakes. It is lower in elevation than both coteau areas that border it.
According to Geography of South Dakota, its difference in elevation from the surrounding land
made it easier for glaciers to become thicker in it, resulting in significantly more erosion.
The Dissected Till Plains- This region of South Dakota is located on the south eastern part of
the state. Just like most the land found in the eastern portion of the state, the Dissected Till Plains
were formed due to glaciation. According to FamilyPedia the rolling hills and fertile land of the
Dissected Till Plains region was formed by an accumulation of left behind loess from the
Wisconsin Glacial period.
The Great Plains- The Great Plains region covers most of the western half of South Dakota.
Physical characteristics of this region are grassy plains, rolling hills, buttes, sand hills and
canyons. According to Wikapedia, erosion from the Black Hills, marine skeletons that fell to the
bottom of an ancient low sea that covered this area, and volcanic material all contribute to the
geology of this region. One of the most noted land features of The Great Plains region is the
Badlands. According to North Dakota State University, the Great Plains has been treeless for the
last 8,000 to 10,000 years, but was not always like that and was once covered with spruce forest
12,000 to 14,000 years ago when the last glacier sheet was present. The Geography of South
Dakota breaks this region into six smaller sub regions which are The Northern Plateau, the
Southern Plateau, The Missouri River Trench, The Coteau Du Missouri, The Pierre Hills, and the
Sand Hills.
The Coteau Du Missouri area lies in between the James River Basin to the east and the
Missouri River to the west. It is 200 miles long with some areas getting 75 miles wide at its north
end all the way down to 25 miles wide at its southern end. This area is known as the western
equal to the Coteau Des Prairies. The Coteau du Missouri is a part of the Missouri Plateau that
has been separated by the Missouri River trench. Coteau du Missouri, just like a big portion of
eastern South Dakota, was shaped and changed by glaciation. The Coteau du Missouri area is
marked with many moraines, hills and valleys, and areas of lowland. According to the
Geography of South Dakota a special feature of this sub region is sags, which are former west to
east running ancient stream valleys that have been covered with glacial drift. There are five sags
that run through the Coteau du Missouri. The one most distinct of the sags is one that lies to the
north of the Ree Hills, and is known as the Great Ree Valley. According to Geological Survey
Professional, the main body of the Coteau du Missouri is made up of Pierre Shale, with the
exception of quartzitic sandstone that caps some of the hills and buttes. There are many hill
formations within the Coteau du Missouri area. The highest of them is a great mesa known as the
Ree Hills, which are located in hand county and are 2,200 feet high.
The Missouri River Trench area is located right through the middle of the state going
down in a general south eastern direction. The Trench separates the Missouri Plateau from the
Coteau du Missouri. The Missouri River Trench is the area surrounding the Missouri River as it
goes through South Dakota. The width of the trench is around a mile wide with some areas up to
four miles wide toward the north. According to the Geological Survey Professional, the side
slopes of the Missouri River Trench are steep, dissected bluffs ranging in height from 300 to
more than 600 feet above the river. During the last glaciation period an ice sheet that covered a
big portion of South Dakota blocked the ability of streams to flow from west to northeast forcing
the streams in a southeast path along preexisting valleys, which is how the Missouri River got its
current path. Even though there are still signs of change from glaciation in the Missouri River
Trench, it is at this sub region that the effects of glaciation in South Dakota start to become much
less noticeable. In fact if a person looked at a map that showed the border of what the glaciers
covered in South Dakota, it follows very closely to the Missouri River line.
Located to the west of the Missouri River Trench is the Pierre Hills sub region. Physical
features of the Pierre Hills are smooth rounded hills and ridges that descend and ascend in a
rollercoaster like fashion. Geologists E.P. Rothrock wrote “The heart of the region, between the
Moreau and White River valleys, is a land of smooth rounded hills which give travelers in our
modern high-speed cars some of the thrills of the roller-coaster in spite of the highway
engineer’s ingenuity in leveling steep grades.” This area is made up of Pierre shale which breaks
down into a sticky clay known as gumbo. It is for this reason that the Pierre Hills sub region is
known as the gumbo area. Among the smooth hills are occasional buttes. The most famous of
these is Medicine Butte, which is 400 foot tall and is located in Lyman County. A special land
feature found in the Pierre Hills is the tepee butte, which is cone shaped and ranges from three
feet up to thirty feet. The tepee butte got its name due to its resemblance to the Native American
tepee.
The Northern Plateau sub region lies west of the Missouri River and covers the north
western part of the state. This land is characterized by a series of sandstone capped terraces
starting from the Missouri River to the border of Montana. Author E.P. Rothrock described this
part of South Dakota as the Cretaceous Table Lands. This is due to the fact that each of the steps
or terraces was caused by a sandstone bottom being left behind during the retreat of the last sea
in South Dakota during the Cretaceous period. There are many buttes that occur throughout the
Northern Plateau sub region. The Cave Hills located in Harding County are the most famous in
this area.
The Southern Plateaus are located west of the Missouri River and South of the Pierre
Hills. The physical characteristics of the Southern Plateau sub region consists of flat grass lands,
deep stream cut valleys, canyons, tables and buttes. This sub region contains the famous
Badlands of South Dakota which can be found in the northern part of the Southern Plateaus
region. Although many badlands formations are located here the Big or White River Badlands
are the most recognized. The Badlands were formed by the erosion of sediments that according
to National Park Service were deposited beginning 69 million years ago when the area was
covered by sea. NPS says that erosion of the Badlands however did not begin until half a million
years ago. According to New World Encyclopedia, during the Oligocene Epoch that took place
between 25 and 40 million years ago, conditions for preservation of extinct animals was
excellent in the Badlands. Badlands National Park currently contains the richest
Eocene/Oligocene Epoch fossil beds in the world. The southern section of the Southern Plateaus
region contains wide buttes and mesas and is known as the Tables. According to The Geography
of South Dakota, some of the famous tables are Cuny Table, Sheep Mountain Table, and Hart
Table, which are over 5 miles in length and width, and are 400 feet high.
The Sand Hills sub region is located at the southern border of South Dakota in the middle
of the western half. This is the smallest of all the regions in South Dakota. The Sand Hills region
in South Dakota is an extension of the Nebraska Sand Hills. The area extends along the border of
South Dakota and Nebraska for about 80 miles with the longest part of it extending into South
Dakota for about 12 miles. The Sand Hills physical characteristics are sand dunes with areas in
between the dunes of flat ground, marshes and lakes. The Sand Hills are ranch country and are
mostly used for grazing cattle. There are however not many ranches located there. Author James
M Crowley wrote, “The Bennett-Mallette-Todd Counties, South Dakota, County-Wide Directory
has detailed maps of roads, towns, and farm/ranch headquarters. It reveals that the South Dakota
Sand Hills have no towns, no railroads, few roads and few ranch headquarters.” So overall the
Sand Hills are a fairly unoccupied place of beautiful rolling sand dunes covered with grass, with
flat land, marshes and lakes in between them. Unfortunately has Author James M Crowley said
in his article The South Dakota Sand Dunes, many tourists never see them because they are
never advertised the way the Black Hills, Badlands or other more famous destinations are.
The Black Hills- The Black Hills Region is a low mountain range located at the far western side
of South Dakota. According to Netstate it covers an area of 6,000 square miles with mountains
that rise from 2,000 to 4,000 feet high. Located in the core of the Black Hills, Harney Peak is the
highest point in South Dakota with a height of 7,242 feet. The Black Hills got its name due to the
fact the pine forest that cover it gives off the appearance of hills being black especially when
viewed from a distance. According to Geology About, The Black Hills were created 70 million
years ago in the Cretaceous age. Eventually the Black Hills eroded exposing the 2 billion year
old Precambrian core, which is the some of the oldest rock in the state of South Dakota. The
Black Hills are surrounded with younger marine rocks from the Paleozoic and Triassic periods
from when ocean covered this area. Many fossils of marine life and rocks from these oceans can
still be found in the Black Hills and surrounding area. During the uplift and creation of the Black
Hills, volcanoes were present. According to Black Hills Visitor, during the later stages of uplift
molten lava was forced upwards created many of the mineral deposits found in the Black Hills
such as gold and silver. The Black Hills also contains copper and lead.
South Dakota has gone through many different stages and changes to get where it today.
The different regions and landforms tell a story of South Dakotas History. Whether a person
enjoys mountains, prairies, lakes, or soft rolling hills South Dakota seems to have something for
everyone.
Work Cited
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SD, Updated 2014. Web. April 21, 2014
http://www.travelsd.com/Destinations
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