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Long Island - Introduction to Oceanography - Lecture Slides, Slides of Oceanography

These are the lecture slides of Oceanography. Key important points are: Long Island, Home Sweet Home, Coastal Features, Beginning, Atlantic Ocean, Million Years Ago, Geological History of Long Island, South America, Culminated, Volcanoes

Typology: Slides

2012/2013

Uploaded on 01/24/2013

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amrusha 🇮🇳

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Long Island: Home Sweet Home
You know that Long Island is an island, but do
you know about the origin of Long Island and
the coastal features that surround it?
Great South Bay
Peconic Bay
Long Island Sound
Shinnecock Bay
www.loving-long-island.com
Docsity.com
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Long Island: Home Sweet Home

  • You know that Long Island is an island, but do you know about the origin of Long Island and the coastal features that surround it?

Great South Bay

Long Island Sound Peconic Bay

Shinnecock Bay

www.loving-long-island.com Docsity.com

In the beginning…

  • The Atlantic Ocean basin originated ~200- million years ago (mya) as the supercontinent Pangaea began drifting apart from seafloor spreading http://upload.wikimedia.org/wikipedia/commons/8/8e/ Pangea_animation_03.gif

http://www.fossilmuseum.net/fossilrecord/Appalachian-Orogenyb.htm

http://en.wikipedia.org/wiki/Allegheny_Plateau

The Last ‘Ice Age’

  • ~110,000 - ~10,000 years ago marked the last (most recent) glacial period
  • During this time, much of the Northern Hemisphere (and to a lesser extent, the Southern Hemisphere) was covered in glaciers
  • Under the extremely cold conditions, these glaciers grew, or advanced

And you thought this winter was cold…

  • Glaciers originating from Canada advanced southward toward present-day Long Island
  • This extensive ice sheet reached Connecticut ~26,000 years ago and the river valley of (now) Long Island ~21,000 years ago
  • This glacier (commonly called the Wisconsin Ice Sheet) covered CT and the surrounding area, widening and deepening the river valley that eventually became Long Island Sound

Stuck between a rock and a hard place

  • The melting of the Wisconsin ice sheet ~20,000 years ago deposited rocks and sediment from within the rocks forming glacial moraines
  • Forms LI’s north shore and ‘backbone’ *Moraines
  • The water melting from the giant ice sheet formed Lake Connecticut (where LIS now stands)
  • As more and more of the ice sheet melted, sea level rose and eventually covered over the coastal plain creating Long Island Sound (saline) ~12,000 years ago

Ice Age: The Final Meltdown

  • Long Island is now surrounded by unique marine environments, but is still changing
  • Currents transport sediments creating barrier beaches, and salt marshes line its estuaries
  • Storms (hurricanes, in particular) are constantly reshaping the profile of Long Island, and even occasionally creating new inlets!

Shinnecock Bay; September 1938

after the Great Hurricane

Storm surge carved out a large section of the barrier island separating Shinnecock Bay from the Atlantic Ocean

Shinnecock Inlet

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The geological future of Long Island

  • As sea levels rise, more and more of Long Island will become submerged (why you need flood insurance if own a house on the south shore…)
  • Alternatively, if sea levels decline, more and more of Long Island would be exposed
  • Earthquakes from isostatic rebound and ancient faults continue to occur