Long island home sweet home
This presentation is the property of its rightful owner.
Sponsored Links
1 / 17

Long Island: Home Sweet Home PowerPoint PPT Presentation


  • 238 Views
  • Uploaded on
  • Presentation posted in: General

Long Island Sound. Peconic Bay. Shinnecock Bay. Great South Bay. www.loving-long-island.com. 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?. In the beginning….

Download Presentation

Long Island: Home Sweet Home

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Long island home sweet home

Long Island Sound

Peconic Bay

Shinnecock Bay

Great South Bay

www.loving-long-island.com

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?


In the beginning

In the beginning…

  • The Atlantic Ocean basin originated ~200-135 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


The geological history of long island

The geological history of Long Island

  • When Pangaea broke apart, it separated what is now South America and Africa, leaving the Appalachian Mountains* as the western border of the emerging Atlantic Ocean basin

    * themselves created ~480 mya from plate collisions that culminated in the construction of Pangaea; once volcanoes


Long island home sweet home

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

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


The geological history of long island1

The geological history of Long Island

  • 200 million years of weathering drastically reduced these mountains in size and deposited large amounts of sediment along the edge of the expanding Atlantic Ocean

  • Gradually, Long Island originated as a river valley as sediments were supplied by the erosion of these coastal plains and the Appalachian Mountains

    • served as a foundation for present-day Long Island


The last ice age

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

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

Wisconsonian Glacier

Stuck between a rock and a hard place

  • As the glaciers spread southward, they scraped up sediment (including bedrock!) and carried it along with them, depositing the accumulated material as they traveled and receded


Stuck between a rock and a hard place1

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


Long island home sweet home

  • 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


The origin of glacial deposits

The origin of glacial deposits


Ice age the final meltdown

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 june 1938

Shinnecock Bay; June 1938


Shinnecock bay september 1938 after the great hurricane

Shinnecock Bay; September 1938 after the Great Hurricane

Shinnecock Inlet

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


The geological future of long island

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


  • Login