GLACIAL LAKE WISCONSIN AFTER THE GLACIERS · PDF filea favorite of photographers. WITCHES...
1
90 94 90 94 12 12 16 16 12 13 13 13 82 23 A Lake Delton Mirror Lake Wisconsin River LOWER DELLS CITY OF WISCONSIN DELLS ROCKY ISLAND REGION LAKE DELTON DAM UPPER DELLS To Milwaukee ROCKY ISLANDS Nature-sculpted craggy cliffs a favorite of photographers. WITCHES GULCH A deep canyon noted for its cool air, which is up to 10 degrees colder than the temperature in the river area. COLD WATER CANYON Offers an endless variety of canyon walls carved by ancient whirlpools. MICH. MICH. ILL. IOWA MINN. IND. OHIO PENN. N.Y. Laurentide Ice Sheet CANADA A LOOK BACK IN TIME Between 2,500 and 3,800 ■ Deposits of sedimentary rocks called sandstone appear in Baraboo. 1,700 ■ There is still no life on land. ■ Fossil magnets today reveal that North America was situated in the tropics, rotated 90 degrees off its present position. ■ Wisconsin was positioned 15 degrees south of the equator. Between 495 and 545 ■Southern continents drift toward the polar regions. ■ Glaciation takes place in the Sahara. ■ Deposits of marine limestone and dolomite appear in Wisconsin. ■ The first fish, shark, and land plants appear. Between 443 and 495 ■ Continents drift toward each other. Dolomite deposits accumulate in Wisconsin. ■ The first insects develop. Between 417 and 443 ■ Giant ferns and club mosses form the Earth’s first forests. ■ The Earth’s first amphibians appear. Between 360 and 417 ■ Wisconsin evolves into a dry land. But the water that drained also washed away deposits from this period. Only sheet-like masses of sedimentary rocks found in adjacent states would later suggest that deposits were once abundant in Wisconsin. Between 248 and 360 ■ The first dinosaurs appear early in the Triassic period, then multiply and roam the Earth through the Jurassic period. ■ But about 65 million years ago, the Earth is struck by a giant asteroid that kills the dinosaurs, triggering their extinction. ■ First mammals and birds evolve. ■ Oil and gas deposits begin to develop. Between 66 and 248 ■ Primates evolve. ■ The Himalayas and the Grand Canyon begin to take shape. Between 66 and 1.8 ARCHAEAN ERA HADEAN ERA PROTEROZOIC ERA PALEOZOIC ERA MESOZOIC ERA CAMBRIAN ORDOVICIAN SILURIAN DEVONIAN CARBONIFEROUS and PERMIAN TERTIARY QUATERNARY ■ The Ice Age puts Wisconsin under a constant cycle of freeze and thaw. ■ Only the southwestern part of the state, later called the driftless area, is spared from the glaciers. ■ The first modern humans evolve. Between 0.01 and 1.8 ■ Granite rocks that have gone through tremendous change in composition begin to form the continent of North America. PRECAMBRIAN EON PHANEROZOIC EON CENOZOIC ERA ■ The Laurentide Ice Sheet, the last of the Quaternary Ice Age glaciers, moves in from Canada. It covers much of Wisconsin and does not recede until 8,000 years later. ■ As the glacier star ts to melt in Wisconsin’s central plain, an ice dam forms a new lake called Glacial Lake Wisconsin. 26,000 years ago 15,000 years ago ■ Eventually, the ice dam bursts and results in a catastrophic flood. ■ The rapid draining in the south side of the glacial lake carves out the lakes, rivers, craggy Pre- cambrian sandstone cliffs and rocks that would form the Dells of the Wisconsin River. ■ The flood lowers the lake level to about 50 feet. 14,000 years ago ■ The Earth’s habitats change as planet warms ■ First evidence of agriculture. ■ Wisconsin’s first humans arrive on the heels of the last glaciation. Between 10,000 and 13,000 years ago ■ The Wolf River batholith, a mass of rock formed by solidified magma, takes form. 1,450 ■ Rampant volcanic activity underneath Lake Superior creates a fissure that threatens to split North America in two. ■ Under water for millions of years, Wisconsin’s Precambrian crust, called the Wisconsin Dome, rises from the sea. 1,100 EON ERA/ PERIOD MILLION YEARS AGO GEOLOGIC DEVELOPMENTS ■ The first multicelled organism develops. ■ The first bacteria on land appear. Between 3,800 and 4,550 ■ The Earth is formed. ■ Life develops in the oceans. Sources: Roadside Geology of Wisconsin by Robert H. Dott Jr. and John W. Attig, 2004; Dictionary of the Earth by John Farndon, 1994; USGS State Geologic Maps; Wisconsin Dells 2005 Travel & Attraction Guide; The Beautiful Dells of the Wisconsin River; Milwaukee Public Museum; WisconsinOnline.com; Answers.com; wisdells.com TRIASSIC / JURASSIC / CRETACEOUS ALFRED ELICIERTO/[email protected] DRIFTLESS AREA GLACIAL LAKE WISCONSIN AREAS GLACIATED IN EARLIER TIMES HOW MUCH OF WISCONSIN WAS COVERED IN ICE SUPERIOR LOBE CHIPPEWA LOBE LANGLADE LOBE WISCONSIN VALLEY LOBE GREEN BAY LOBE LAKE MICHIGAN LOBE ■ The ice sheet was several hundred feet thick in most parts. It came in six lobes, blanketing the state’s northern highlands and eastern ridges and lowlands. ■ Only the southwestern uplands were left untouched by the glacier. This area would later be known as the driftless area. Although Wisconsin’s most recent Ice Age started 90,000 years ago, the glacier that had the greatest impact on the state’s modern landscape was the Laurentide Ice Sheet. This final glacier moved in from Canada 26,000 years ago and reached its maximum extent of coverage in the northern American Midwest about 18,000 years ago. THE LAST GLACIATION When the ice melted, it formed a huge ice dam on both sides of the Wisconsin River, covering what today would be an 1,825-square-mile swath of land from Stevens Point in the north to Devils Lake in the south, Tomah in the west to Baraboo and Wisconsin Dells in the east. It was a frozen lake roughly as big as Utah’s modern-day Great Salt Lake. ■ The glacial lake, estimated to be about 150 feet deep, was backstopped in the east by the Johnstown moraine, an accumulation of earth and stones deposited by earlier glaciers. Stretching north to south from Stevens Point to Devils Lake, the moraine took shape during the multiple glaciations that started 90,000 years before. GLACIAL LAKE WISCONSIN MORAINE TRAIL TILL OUTWASH LAKE BASINS DRIFTLESS AREA AFTER THE GLACIERS Wisconsin’s geologic map after the last ice sheet washed away: DEVONIAN SILURIAN ORDOVICIAN CAMBRIAN PRECAMBRIAN ROCKS TELL THE STORY The state’s geologic past can be gleaned from the rocks that make up its cliffs. Devils Lake Wisconsin River La Crosse Mississippi River Milwaukee WEST EAST Almost 2 billion years ago, the “Water Park Capital of the World” was literally under water. Positioned just south of the equator and drenched in a tropical climate, the large mass of rock that would become the Wisconsin dome broke out of water to rise above sea level a billion years ago. From then on, Wisconsin evolved into a dry land as plant and animal life began to appear, and dinosaurs roamed the Earth and eventually died off. But it was the final retreat of the glaciers that carved the rivers, lakes, canyons and rocky cliffs that gave shape to the geological gem that is Wisconsin Dells. THE DELLS OF THE WISCONSIN RIVER A N I CE A GE C REATION THE DELLS TODAY Wisconsin’s oldest and most famous tourist attraction is made up of a seven-mile-long network of rivers, lakes and canyons, as deep as 100 feet in some parts, carved into Cambrian sandstone by the rapid draining of the Cenozoic Age-Glacial Lake Wisconsin about 15,000 years ago. It is a work of transformation from the sandy, wind-blown, treeless landscape of 500 million years ago. Over the years, Wisconsin Dells has parlayed its natural beauty into a giant, year-round amusement park. The Dells offers all sorts of thrills – from scenic riverboat cruises and water rides on any one of more than 200 waterslides during the summer, to downhill skiing and snowmo- bile rides across 80 miles of trails. Baraboo Hills NORTHWEST SOUTHEAST Johnstown moraine Note: Vertical scale is exaggerated Outwash plain at Sauk Prairie PROFILE OF THE GLACIAL LAKE AND SURROUNDING TOPOGRAPHY Johnstown moraine near Wisconsin Dells Northwest outlet Glacial Lake Wisconsin Lake Merrimac Lewiston Basin 10 MILES 50 FEET ■ The Wisconsin River is dammed for the first time at the site of the present city of Wisconsin Dells to generate power for the new settlement. But lumbermen who ply the route blow up the dam because it obstructs their log rafts. Direct railroad service makes the Dells easily accessible from Milwaukee, Chicago, Minneapolis-St. Paul and St. Louis. 1856 ■ Tourism declines and the Dells gradually evolves into a giant amusement park. Early 1900s ■ A hydroelectric dam is built, raising the level of the Upper Dells about 16 feet. The raised water drowns some geological features. 1909 ■ Special excursion trains and steamboat tours on the river bring droves of people who marvel at the grandeur of the sculpted gorges and rock cliffs. Late 1800s ■ French fur traders and missionaries use the Wisconsin River to ferry goods. 1600s to 1700s SOME MODERN-DAY MILESTONES Pittsville Friendship Necedah Camp Douglas Mauston Elroy Reedsburg Portage Baraboo Devils Lake Warrens Black River Falls Tomah Sparta Stevens Point Wisconsin Rapids Wisconsin River Kickapoo River La Crosse River Black River 0 40 Miles Johnstown moraine, formed by earlier glaciers Wisconsin Dells
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Transcript of GLACIAL LAKE WISCONSIN AFTER THE GLACIERS · PDF filea favorite of photographers. WITCHES...
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A
LakeDelton
MirrorLake
Wisconsin River
LOWERDELLS
C ITY OFWISCONS IN DELLS
ROCKY ISLANDREGION
LAKEDELTON
DAM
UPPERDELLS
To Milwaukee
ROCKY ISLANDSNature-sculpted craggy cliffs a favorite of photographers.
WITCHESGULCHA deep canyon noted for its cool air, which is up to 10 degrees colder than the temperature in the river area.
COLD WATER CANYONOffers an endless variety of canyon walls carved by ancient whirlpools.
MICH.
MICH.
ILL.
IOWA
MINN.
IND. OHIO PENN.
N.Y.
LaurentideIce Sheet
C A N A D A
A LOOK BACK IN TIME
Between 2,500 and 3,800
■ Deposits of sedimentary rocks called sandstone appear in Baraboo.
1,700
■ There is still no life on land.■ Fossil magnets today reveal that North America was situated in the tropics, rotated 90 degrees off its present position.■ Wisconsin was positioned 15 degrees south of the equator.
Between 495 and 545
■Southern continents drift toward the polar regions. ■ Glaciation takes place in the Sahara.■ Deposits of marine limestone and dolomite appear in Wisconsin.■ The first fish, shark, and land plants appear.
Between 443 and 495
■ Continents drift toward each other. Dolomite deposits accumulate in Wisconsin.■ The first insects develop.
Between 417 and 443
■ Giant ferns and club mosses form the Earth’s first forests. ■ The Earth’s first amphibians appear.
Between 360 and 417
■ Wisconsin evolves into a dry land. But the water that drained also washed away deposits from this period. Only sheet-like masses of sedimentary rocks found in adjacent states would later suggest that deposits were once abundant in Wisconsin.
Between 248 and 360
■ The first dinosaurs appear early in the Triassic period, then multiply and roam the Earth through the Jurassic period. ■ But about 65 million years ago, the Earth is struck by a giant asteroid that kills the dinosaurs, triggering their extinction.■ First mammals and birds evolve.■ Oil and gas deposits begin to develop.
Between 66 and 248
■ Primates evolve. ■ The Himalayas and the Grand Canyon begin to take shape.
Between66 and 1.8
ARCH
AEAN
ERA
HADE
ANER
APR
OTER
OZOI
C E
RAPA
LEOZ
OIC
ERA
MES
OZOI
C E
RA
CAM
BRIA
NOR
DOVI
CIAN
SILU
RIAN
DEVO
NIAN
CARB
ONIF
EROU
San
d PE
RMIA
NTE
RTIA
RYQU
ATER
NARY ■ The Ice Age puts Wisconsin
under a constant cycle of freeze and thaw.■ Only the southwestern part of the state, later called the driftless area, is spared from the glaciers.■ The first modern humans evolve.
Between 0.01 and 1.8
■ Granite rocks that have gone through tremendous change in composition begin to form the continent of North America.
PREC
AMBR
IAN
EON
PHAN
EROZ
OIC
EON
CENO
ZOIC
ERA
■ The Laurentide Ice Sheet, the last of the Quaternary Ice Age glaciers, moves in from Canada. It covers much of Wisconsin and does not recede until 8,000 years later.
■ As the glacier starts to melt in Wisconsin’s central plain, an ice dam forms a new lake called Glacial Lake Wisconsin.
26,000 years ago
15,000 years ago
■ Eventually, the ice dam bursts and results in a catastrophic flood. ■ The rapid draining in the south side of the glacial lake carves out the lakes, rivers, craggy Pre- cambrian sandstone cliffs and rocks that would form the Dellsof the Wisconsin River.■ The flood lowers the lakelevel to about 50 feet.
14,000 years ago
■ The Earth’s habitats change as planet warms■ First evidence of agriculture.■ Wisconsin’s first humans arrive on the heels of the last glaciation.
Between10,000 and 13,000 years ago
■ The Wolf River batholith, a mass of rock formed by solidified magma, takes form.
1,450
■ Rampant volcanic activity underneath Lake Superior creates a fissure that threatens to split North America in two.■ Under water for millions of years, Wisconsin’s Precambrian crust, called the Wisconsin Dome, rises from the sea.
1,100
EONERA/
PERIODMILLION
YEARS AGO GEOLOGIC DEVELOPMENTS
■ The first multicelled organism develops.■ The first bacteria on land appear.
Between 3,800 and 4,550
■ The Earth is formed. ■ Life develops in the oceans.
Sources: Roadside Geology of Wisconsin by Robert H. Dott Jr. and John W. Attig, 2004; Dictionary of the Earth by John Farndon, 1994; USGS State Geologic Maps; Wisconsin Dells 2005 Travel & Attraction Guide; The Beautiful Dells of the Wisconsin River; Milwaukee Public Museum; WisconsinOnline.com; Answers.com; wisdells.com
TRIA
SSIC
/ JU
RASS
IC /
CRET
ACEO
US
ALFRED ELICIERTO/aelicier [email protected]
DRIFTLESS AREA
GLACIAL LAKEWISCONSIN
AREAS GLACIATEDIN EARLIER TIMES
HOW MUCH OF WISCONSINWAS COVERED IN ICE
SUPERIORLOBE
CHIPPEWALOBE
LANGLADELOBE
WISCONSINVALLEYLOBE
GREENBAY
LOBE
LAKE MICHIGAN LOBE
■ The ice sheet was several hundred feet thick in most parts. It came in six lobes, blanketing the state’s northern highlands and eastern ridges and lowlands.
■ Only the southwestern uplands were left untouched by the glacier. This area would later be known as the driftless area.
Although Wisconsin’s most recent Ice Age started 90,000 years ago, the glacier that had the greatest impact on the state’s modern landscape was the Laurentide Ice Sheet. This final glacier moved in from Canada 26,000 years ago and reached its maximum extent of coverage in the northern American Midwest about 18,000 years ago.
THE LAST GLACIATIONWhen the ice melted, it formed a huge ice dam on both sides of the Wisconsin River, covering what today would be an 1,825-square-mile swath of land from Stevens Point in the north to Devils Lake in the south, Tomah in the west to Baraboo and Wisconsin Dells in the east. It was a frozen lake roughly as big as Utah’s modern-day Great Salt Lake.■ The glacial lake, estimated to be about 150 feet deep, was backstopped in the east by the Johnstown moraine, an accumulation of earth and stones deposited by earlier glaciers. Stretching north to south from Stevens Point to Devils Lake, the moraine took shape during the multiple glaciations that star ted 90,000 years before.
GLACIAL LAKE WISCONSINMORAINE TRAILTILLOUTWASHLAKE BASINSDRIFTLESS AREA
AFTER THE GLACIERSWisconsin’s geologic map after the last ice sheet washed away:
DEVONIANSILURIANORDOVICIANCAMBRIANPRECAMBRIAN
ROCKS TELL THE STORYThe state’s geologic past can be gleaned from the rocks that make up its cliffs.
DevilsLake
Wisconsin River
La Crosse
Mississippi RiverMilwaukee
WEST EAST
Almost 2 billion years ago, the “Water Park Capital of the World” was literally under water. Positioned just south of the equator and drenched in a tropical climate, the large mass of rock that would become the Wisconsin dome broke out of water to rise above sea level a billion years ago. From then on, Wisconsin
evolved into a dry land as plant and animal life began to appear, and dinosaurs roamed the Earth and eventually died off. But it was the final retreat of the glaciers that carved the rivers, lakes, canyons and rocky cliffs that gave shape to the geological gem that is Wisconsin Dells.
THE DELLS OF THE W ISCONS IN R IVER
AN ICE AGE CREATION
THE DELLS TODAY
Wisconsin’s oldest and most famous tourist attraction is made up of a seven-mile-long network of rivers, lakes and canyons, as deep as 100 feet in some parts, carved into Cambrian sandstone by the rapid draining of the Cenozoic Age-Glacial Lake Wisconsin about 15,000 years ago. It is a work of transformation from the sandy, wind-blown, treeless landscape of 500 million years ago. Over the years, Wisconsin Dells has parlayed its natural beauty into a giant, year-round amusement park. The Dells offers all sorts of thrills – from scenic riverboat cruises and water rides on any one of more than 200 waterslides during the summer, to downhill skiing and snowmo-bile rides across 80 miles of trails.
BarabooHills
NORTHWESTSOUTHEAST
Johnstownmoraine
Note:Vertical scaleis exaggerated
Outwash plainat Sauk Prairie
PROFILE OF THE GLACIAL LAKEAND SURROUNDING TOPOGRAPHY
Johnstown morainenear Wisconsin Dells
Northwestoutlet
Glacial LakeWisconsin
LakeMerrimac
LewistonBasin
10 MILES
50 FEET
■ The Wisconsin River is dammed for the first time at the site of the present city of Wisconsin Dells to generate power for the new settlement. But lumbermen who ply the route blow up the dam because it obstructs their log rafts. Direct railroad service makes the Dells easily accessible from Milwaukee, Chicago, Minneapolis-St. Paul andSt. Louis.
1856
■ Tourism declines and the Dells gradually evolves into a giant amusement park.
Early 1900s
■ A hydroelectric dam is built, raising the level of the Upper Dells about 16 feet. The raised water drowns some geological features.
1909
■ Special excursion trains and steamboat tours on the river bring droves of people who marvel at the grandeur of the sculpted gorges and rock cliffs.
Late 1800s
■ French fur traders and missionaries use the Wisconsin River to ferry goods.
1600s to 1700s
SOME MODERN-DAY MILESTONES
Pittsville
FriendshipNecedah
CampDouglas
MaustonElroy
Reedsburg PortageBaraboo
Devils Lake
Warrens
Black RiverFalls
TomahSparta
StevensPoint
WisconsinRapids
Wis
cons
inRi
ver
Kick
apoo
Riv
er
La CrosseRiver
Black River
0 40Miles
Johnstown moraine, formed by earlier glaciers
WisconsinDells
