The Geological History of Connecticut Presentation

The Geological History of Connecticut Presentation

This presentation, given at Hillcrest Middle School for 7th grade students on January 15, 2013, explores the influence of geology on the Connecticut landscape. Ralph Lewis, a

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PowerPoint presentation about 'The Geological History of Connecticut Presentation'. This presentation describes the topic on This presentation, given at Hillcrest Middle School for 7th grade students on January 15, 2013, explores the influence of geology on the Connecticut landscape. Ralph Lewis, a. The key topics included in this slideshow are . Download this presentation absolutely free.

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Slide1The Geological History ofConnecticut Presentation for Hillcrest Middle School Grade 7 January 15, 2013

Slide2from: the influence of geology on the connecticut LandscapePhoto Essay by Ralph Lewis, Retired Connecticut State Geologist The Tectonic Plates Today

Slide6from: the influence of geology on the connecticut LandscapePhoto Essay by Ralph Lewis, Retired Connecticut State Geologist

Slide7750 million years ago (precambrian time), the east coast ofNorth America was at westernmost Connecticut. Everything to the east was added later on, piece by piece, as continents collided, and closed up the  Iapetos  Ocean . The continent of  Pangea   was created.

Slide8About 200 million years ago,Pangea began  to break apart and the  Atlantic Ocean  was born.

Slide9 The Appalachian Mountains may once have been as high as the Himalayas! Folded gneiss, northwest  Connecticut

Slide10As the Atlantic Ocean grew, other large cracks orrifts formed in the Hartford Basin.   Lava flooded into these basins.

Slide11These ridges  in New Haven are the remnants of magma that flowed through the rifts and flooded the area. This is East Rock.

Slide12Rifting occurred throughout Jurassic time (213-144 Ma), alternating  with quiet times  where hardened lava and other rocks were  eroded and deposited  in many layers. Intersection of Rte. 9 & 72, Berlin

Slide13from: the influence of geology on the connecticut LandscapePhoto Essay by Ralph Lewis, Retired Connecticut State Geologist Different parts of Connecticut Came from Different Places Iapetos= Former Ocean Newark= Connecticut Valley Proto North America= Former Continent Avalonia= Former Continent

Slide14Weathering, Erosion andDeposition of rocks and sediments in Connecticut Some geologists believe that up to 30 km (18.63 miles)  of the bedrock cover has been removed from Connecticut during this period!

Slide15Rocks that were more resistant to erosion (harder)  became the ridges and high points of land we see today. Old Mine Park, Trumbull Indian Well Falls,  Shelton

Slide16Areas with many faults and fractures, or lessresistant (softer) bedrock became the south-draining valleys and lowlands. Connecticut River, East Hampton Stream deposition at Savin Rock, West Haven

Slide17While the forces that created thebedrock of Connecticut were occurring over hundreds of millions of years, smaller cycles of glacial warming and cooling  were occurring every  200,000 years or so.

Slide18the northern half of most of north america has beencovered by a continental ice sheet up to 2 miles thick! This happened 4 times over the last 2 million years!   26,000 years ago (Pleistocene times), the ice sheet was thick enough to completely cover Mt. Washington in New Hampshire.


Slide20Greenland TodayIce Sheet

Slide21Glaciers move  over the land,  scraping away rocks  and  transporting sediment

Slide2215,500 years ago, the ice sheet had nearlymelted out of Connecticut. Evidence of glaciation can be found throughout the state. End Moraine at Silver Sands State Park in Milford Striations or scratches on West Rock Ridge in New Haven Glacial erratic boulders in Ledyard

Slide23Glacial Evidence & Deposits in Connecticut

Slide24Connecticut Glacial Retreat – moraine ages