Geological Features of

Rocky Neck State Park

Rocky Neck State Park is located on the shore of Long Island Sound in East Lyme Connecticut

Rocky Neck State Park Location

Rocky Neck

Known by Native Americans and Colonists for it’s abundance of wildlife and fish

The park was first founded in 1931710 acres were set aside for:

beach goers on it’s rock free white beaches and it clear waters

Hikers to walk on many of it’s diverse trails trough caves and scenic salt marshes

Campers to use one of it’s 160 campsites Bird watchers to observe many of species such as

Cranes , Herons, Swans, and Osprey that utilize Bride Brook salt marsh

Rocky Neck State Park Information

Map Of the Park

Rocky Neck has many geological formations that represent both glacial and tectonic activity.

Why Rocky Neck State Park?

450-250 million years ago (Paleozoic era) several crustal plates including Avalonia (island in Atlantic) Africa and Eurasia collide into the Proto North America plate closing the Lapetos Ocean

Collision caused metamorphic changes in the rock causing folding and the creation of the Appalachian mountains

235 million years (Mesozoic era) plate tectonics had reversed and the super continent known as Pangaea started to break apart causing rift basins to form along the break up

Avalonia stayed attached to North America (southeast Ct)

Tectonic history Rocky Neck State ParkProto North America

AvaloniaRift Valley

Metamorphic Rock- Is transformation of one rock type into another as a result of exposure of intense heat or pressure and forms compressed mineral layers

Tectonic history Rocky Neck State Park

Compressed layers of Granitic Gneiss

Tectonic activity compressed the land forming ridges running north and south through out the park forming crescent shaped beaches

Evidence of Tectonic Activity

West Headland

East Headland

Crescent Beach

When the land is compressed near the coast line salt marshes often fill in the valley

Evidence of Tectonic Activity cont.

West ridge East ridgeSalt Marsh

Compression of plates has resulted rocks to metamorphosis and fold under pressure and heat

Evidence of Tectonic Activity cont.

Potter Hill Granitic gneiss

Streaks of pink granite

Other MineralsPink-Orange

FeldsparQuartzGraniteTourmalineBiotite

Evidence of Tectonic Activity cont.

Potter Hill

Granitic gneissMetamorphic

rock, formed from intense heat and pressure during formation

Banded texture of elongated mierals

Evidence of Tectonic Activity cont.

Granitic gneiss

Pegmatite veins in granitic gneiss rock found on Potter Hill

Formed under less pressure and heat

Evidence of Tectonic Activity cont.

Pegmatite vein

More ridges as a result of compression from east to westWoodland

environment

Evidence of Tectonic Activity cont.

West ridge East ridge

24,000 years ago Connecticut was covered by glacier

For 5,000 years the glacial boundary stayed over Connecticut containing large amounts of loose sediments, sand, rocks, and clay which form terminal moraines marking the furthest boundary of the glacier

Glacial History Rocky Neck State Park

Glacial till consists of loose sediments rocks, sand, and clay covered much of CT’s coastal bedrock

Evidence of Glacial Activity

Glacial Till

Rocks, sand, and clay make up the terminal moraines marking the glaciers boundary and formed: Long Island, Block Island, Martha’s Vineyard, Nantucket, and Cape Cod

Evidence of Glacial Activity cont.Glacial direction

N

S

Long Island

Glacial BouldersAre moved

from the north during glacial movement south

Evidence of Glacial Activity cont.

Glacial Boulders

Glacial polishing on Potter HillAs the

glacier glides over the rock the ice acts like sandpaper, scratching the bedrock

Evidence of Glacial Activity cont.

Glacial polishing

Local rock was carved to make the pavilion

Facilities

http://www.ct.gov/dep/cwp/view.asp?a=2716&q=325108&depNav_GID=1650 (2008)

Work Cited

Write a paragraph describing how tectonic activity has shaped Rocky Neck State Park

In your paragraph explain two sources of evidence of tectonic activity at the park

Write a paragraph describing how glacial activity has shaped Rock Neck State Park

In your paragraph explain two sources of evidence of tectonic activity at the park

Assessment