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Roger Weller, geology instructor                             

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Niagara Falls
April Mangum
Physical Geology
Fall 2005

                                                              Niagara Falls

 

The Niagara Falls are categorized into three names

The American Falls

The Horseshoe Falls

The Bride Veil Falls

 

Ice Age history of the Niagara River and the Whirlpool Rapids

 

Roy Terrace the birth site of Niagara FallsThe Niagara Falls was once a sheet of ice approximately 18,000 years ago.  The southern region of Ontario was covered by 2-3 kilometers thick of ice as the sheet moved south the ice gouged out the basins of what is now known as the Great Lakes.  Then as the ice melted north for the last time, it released large amounts of the melt waters into those recently gouged out basins.  If you think about it the water in those lakes is fossil water or ancient water, and only less than 1% of that water is renewable on an annual basis.

 









 

 

Niagara Peninsula Becoming the Whirlpool
 

The Niagara Peninsula was free from the ice about or approximately 12,500 years ago.  As it retreated north, its melt waters began to flow through what are now Lake Erie, lake Ontario and Niagara River to the St. Lawrence River ending up at the Ocean. 

 

Then approximately 10,500 years ago, geological effects were taking place through an isostatic rebound.  Then it was interrupted.  The glacial melt waters go rerouted through northern Ontario, going around the southern route.  Lake Erie was only half its size it is now about 5,000 years ago because of it.  The Niagara River’s flow was reduced by about 10% and it halted in the Niagara Glen area.  The melt waters were then rerouted once again through southern Ontario restoring the fall to their original strength.  That is when it reached the Whirlpool.

 

The entanglement that went on there was a strong and short encounter, lasting only weeks, could have been only days according to geologists.  In those days or weeks, the Niagara River intertwined with an old riverbed, one that was buried and sealed during the previous ice age.  The then became a buried gorge; it tore out the glacial debris and scoured the old riverbed clean.  More than likely it was not a falls but a churning rapid then.  When everything was done, it left a 90-degree turn in the river and that is what we now call the Whirlpool Rapids.  http://www.niagarafrontier.com/whirlpoolrapids.html The falls were then re-established around the Whirlpool Rapids Bridge up the river to the right, and carved its way through the rock to where it is today.  http://www.whirlpooljet.com/07_video/whirlpool_high.wmv








 

 

TIMELINE

YEARS AGO

EVENT

430 - 415 million

rocks of the Niagara Escarpment

295 million

Appalachian Mountains

225 - 83 million

Triassic, Jurassic Period (dinosaurs roam earth)

83 - 60 million

dinosaurs extinct

1.5 million

earliest man in Africa

14 thousand

continental glaciers in Northern Hemisphere at their maximum extension

14 - 12 thousand

Wisconsin Glacier cover – retreats

12 thousand

Niagara Falls begins

12 - 11 thousand

Lower Great Gorge

10 - 6 thousand

Whirlpool Rapids Gorge

6 thousand

modern Lake Erie

5 thousand

Upper Great Gorge

Niagara Falls

Niagara Falls - Erosion ChartNiagara Falls has eroded 11.4 kilometers (7.1 miles) during the last 12,300 years.

The slowing of the erosion rate is caused by two major factors:

1) The erosion resistant limestone cap the rock of the falls of Niagara they have been flowing over.  This limestone layer began approximately ˝ kilometer north of the Rainbow Bridge.  As the Falls erode southward, the erosion rate will increase when it reaches Navy Island where the Falls reach a softer layer of rock.

2) The development of hydroelectric generating plants along the shoreline of the Niagara River has vastly reduced the rate of water flow through water diversion.

Just Credit Info and Photo to http://www.niagarafrontier.com/whirlpoolrapids.html







 

 

·          The Niagara Falls attracts more than 12 Million people a year.  The river falls over a cliff of dolostone and shale.  The Niagara Falls is the second largest falls on earth next to the Victoria Falls in Africa.  Being as it is one of the largest falls in the world.  The Great Lakes along with the fall helps supply 1/5 of the world’s fresh water.  The Niagara District sedimentary deposits include sandstone, shale, and marine limestone Just credit photo to Niagara Falls Thunder Alley

                                            

 

PUBLISHED RATES OF RECESSION OF NIAGARA FALLS

From

To

Interval

American Falls

Horseshoe Falls

1842

1875

33 years

0.23 m/yr.

0.61 - 1.34 m/yr.

1842

1890

48 years

0.20 m/yr.

0.66 m/yr.

1842

1905

63 years

very little

1.16-1.61 m/yr.

1842

1911

69 years

n/a

1.52 m/yr.

1875

1886

11 years

0.03 m/yr.

0.57 m/yr.

1875

1905

30 years

n/a

1.70-2.01 m/yr.

1886

1890

4 years

0.50 m/yr.

1.52 m/yr.

1905

1927

22 years

very little

0.70 m/yr.

 

Pictures of Historic Niagara Falls

http://www.niagarafrontier.com/tashapageone.html

http://www.niagarafrontier.com/tashapagetwo.html

 

 



Here are some photos I took April 2005

 

 

 

 

 

 

 

 

 

 

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Works Cited

 

The best Web site I found for pictures and Video

http://www.infoniagara.com/attractions/falls/flash/american.html

 

Other sites

http://school.discovery.com/lessonplans/programs/niagarafalls/q.html

http://www.abacast.com/download/webinstall/index/.php?

http://niagarafallslive.com

http://iaw.com/~falls/origins.html#a

http://www.infoniagara.com/other/fast_facts/index.html

http://www.infoniagara.com/other/history/geo.html