Drain the great lakes video sheet (Final)

Is the bottom of lake superior smooth and flat like a bathtub?

NO

what landscape feature is at the bottom of lake superior

Valleys

Nigel wattrus & his team from large lakes observatory in duluth have been doing what?

Map areas of lake superior

what was really carving the huge hidden valleys of lake superior

Ice and melt water

What is so impressive about the bridge over the straits of mackinac

longest bridge in the western hemisphere (5 miles)

once a year on labor day what can people do on the bridge over mackinac

walk the bridge

have water levels on the great lakes fluctuated widely

Yes

Thanks to mapping the lakes once drained how much lower than present elevation

164 ft lower than today (50 meters)

how long ago did the lakes drain that much

7000-10,000 yrs ago

further mapping revealed what features existed off the bruce peninsula 7000 yrs ago

waterfalls and river channels

back then what was in the gorge in the straits of mackinac

river

in the middle of lake huron what striking feature emerges if u drain the lake

alpina ridge

what type of constructions have been created on the alpina ridge of lake huron

stone constructions

what purpose may earlier humans have built stone constructions

Hunting technique

In lake Erie what is unique about the 25-mile peninsula extending out into the lake

a land formation

what is the land formation called

Long point

how deep is the sand of long point

65 meters

the water over niagara falls continually cuts back the gorge and since the retreat of the glaciers the falls have moved upstream closer to lake erie by how many miles

7 miles

if you go back 5000 to 10000 years ago what did Niagara falls look like

a river going over basins

the great lakes are under a lot of pressure from what

tectonic plates-earthquakes

tectonic plates/earthquakes cause what feature to appear on the floor of lake Ontario

popups

at the eastern end of Lake Ontario what feature lies underneath at charity shoal

circular area (crater)

what in arizona is comparable to charity shoal

best preserved crater in the world

how many shipwrecks are at the bottom of the great lakes

6000

why so many shipwrecks at the bottom of the great lakes

due to a lot of shipping

What invasive species entered the lakes in 1980s

Mussels

Which Great Lake has the highest amount of mussels

Michigan

At the “three brothers shipwreck” what have the mussels done to the ship

Algae growth

In Lake Superior near whitefish point is what famous shipwreck

1975 Edmund Fitzgerald

The storm that sunk the Edmund Fitzgerald was so powerful what did it do to the ship

Ripped it in half

Of the 29 men who perished on the Edmund Fitzgerald where are they now

Still down there