The SeafloorThe Seafloor

The oceans are The oceans are classified into four classified into four major basinsmajor basins

PacificPacific AtlanticAtlantic IndianIndian ArcticArctic

Oceans of the WorldOceans of the World

The Origin and The Origin and Structure of the Structure of the Ocean BasinsOcean Basins

Structure of EarthStructure of Earth CoreCore-innermost layer, iron-rich, high pressure, -innermost layer, iron-rich, high pressure,

4000 degrees Celsius4000 degrees Celsius MantleMantle-outside core, very hot, semi-plastic, -outside core, very hot, semi-plastic,

flows and swirls around slowly like thick liquidflows and swirls around slowly like thick liquid CrustCrust-outermost layer, very thin, like rigid skin -outermost layer, very thin, like rigid skin

atop mantleatop mantle--OceanicOceanic-sea floor, composed of -sea floor, composed of basalt basalt

mineral mineral (darker color and denser)(darker color and denser)

--ContinentalContinental-composed of -composed of granitegranite (light color), (light color),

thick blocks of crust floating on mantlethick blocks of crust floating on mantle

Continental DriftContinental Drift

Alfred WegenerAlfred Wegener

19121912 Suggested Suggested

“supercontinent”“supercontinent” PangaeaPangaea By 1960s Scientists By 1960s Scientists

concluded the concluded the continents did drift continents did drift

Plate TectonicsPlate Tectonics

Mid–Ocean RidgeMid–Ocean Ridge

SoNAR allowed the formation of SoNAR allowed the formation of detailed surveys of the ocean floordetailed surveys of the ocean floor

The mid ocean ridge system was The mid ocean ridge system was discovereddiscovered

Sound travels through air at about Sound travels through air at about 337 meters pr second.337 meters pr second.

Through water at 1460 meters per Through water at 1460 meters per second! Explain……second! Explain……

Cross Section of Mid Cross Section of Mid Ocean-ridge Ocean-ridge

Sea-Floor SpreadingSea-Floor Spreading

Subduction-The Subduction-The downward downward movement of a movement of a plateplate

GEOLOGICAL GEOLOGICAL STRUCTURE OF STRUCTURE OF THE OCEANTHE OCEAN

Continental shelfContinental shelf

Gently sloping, Gently sloping, shallow shallow

Continental slopeContinental slope

Steeper, extends Steeper, extends seaward from seaward from shelfshelf

Abyssal plainAbyssal plain

Relatively flat, Relatively flat, contains contains seamounts and seamounts and trenchestrenches

Mid-Ocean Ridge and Mid-Ocean Ridge and Hydrothermal VentsHydrothermal Vents

Up to 660 F Up to 660 F Releases sulfidesReleases sulfides

HISTORY OF HISTORY OF L.I.S.L.I.S.

DimensionsDimensions

110 miles long110 miles long 21 miles at the widest pt.21 miles at the widest pt. 248 miles of beach (only 95 public)248 miles of beach (only 95 public) Avr. Depth 65 feetAvr. Depth 65 feet 44 sewer treatment plants!!!!44 sewer treatment plants!!!! 32-75 F temp.32-75 F temp.

200 MYA.-North America and Africa 200 MYA.-North America and Africa drift away from each other.drift away from each other.

3 Mya. Glaciers covered the land 3 Mya. Glaciers covered the land from Canada to Connecticut.from Canada to Connecticut.

Sea level dropped. Why?Sea level dropped. Why?

22,000 years ago The glaciers 22,000 years ago The glaciers reached the southernmost point reached the southernmost point (the middle of Long Island)(the middle of Long Island)

The ocean was 350 feet lower than The ocean was 350 feet lower than it is today.it is today.

The coastline was 150 miles south The coastline was 150 miles south of Long Island.of Long Island.

Glacier pluckingGlacier plucking

Glacier pluckingGlacier plucking

The ice began to melt leaving The ice began to melt leaving deposits of sand and rocks in deposits of sand and rocks in moraines.moraines.

This formed a freshwater lake from This formed a freshwater lake from the melting ice.the melting ice.

The lake accumulated to a depth The lake accumulated to a depth of 500 feet (350 feet current max. of 500 feet (350 feet current max. depth :the race)depth :the race)

The freshwater broke through The freshwater broke through forming the raceforming the race

8,000 years ago seawater began to 8,000 years ago seawater began to flow back into the lake.flow back into the lake.

As the water level went up a As the water level went up a second opening occurred near second opening occurred near NYC. called Hells Gate NYC. called Hells Gate

Now known as an estuary Now known as an estuary

EstuaryEstuary

A partly enclosed coastal body of A partly enclosed coastal body of water where seawater and water where seawater and freshwater meet and mix.freshwater meet and mix.

Soon after the glaciers began to Soon after the glaciers began to melt the first humans reached the melt the first humans reached the coast. WHY?coast. WHY?

In the 1600’s Ct. had one of the In the 1600’s Ct. had one of the densest pop. of Native Americans densest pop. of Native Americans in the U.S.in the U.S.

1614- Adriaen Block- Dutch 1614- Adriaen Block- Dutch explorer sailed through Hells Gate, explorer sailed through Hells Gate, out at the Race and on to Block out at the Race and on to Block Island.Island.

He then went up the Connecticut He then went up the Connecticut river to what is now Hartford.river to what is now Hartford.

SettlersSettlers

1630’s- English and Dutch settlers 1630’s- English and Dutch settlers “purchased” land from Native “purchased” land from Native Americans.Americans.

Maritime developmentMaritime development

1700’s- Trade routes between Ct. 1700’s- Trade routes between Ct. and West Indies.and West Indies.

Sugar, Molasses for cattle, pig.Sugar, Molasses for cattle, pig.

WARWAR

The British occupied Long Island The British occupied Long Island but not CT.but not CT.

CT…Home of the Privateers.CT…Home of the Privateers.

Ship buildingShip building WhalingWhaling OysteringOystering Fishing……What happen to the Fishing……What happen to the

Samon etc.?Samon etc.?

TransportationTransportation

The New Haven RRThe New Haven RR I95I95 Rec. BoatsRec. Boats

IndustryIndustry

Once farming, now cities….Once farming, now cities…. Factories for guns, clothes, clocks Factories for guns, clothes, clocks

and locks…and locks…

ESSAYESSAY

Explain how Long Island Sound Explain how Long Island Sound was created.was created.

Include : effects of Glaciers, Plate Include : effects of Glaciers, Plate tectonics ,salt vs freshwater, tectonics ,salt vs freshwater, human impact and time. human impact and time.