Plate Movements, Continents and Connecticut: A Guide to Big Ideas

Why is Connecticut so Amazing?

• Connecticut shows evidence of various earth processes, such as continental collisions, rifting, and folding that have shaped its structure.

Once Upon A Time

• Some time over 1 billion years ago, there was an ancient land mass called “Proto- North America”

• Proto North America eventually became the North American continent.

• About 1 billion years ago, another continent collided with proto-North America.

A Big CRUNCH• Sediments (rock pieces) were caught in

between and pushed up onto North America.

• The collision crumpled the crust, creating a tall mountain range that stretched from Canada to Mexico: the Grenville Mountains.

• These mountains are the earliest evidence of mountain building in our region, and

Where Did They Go?

•Over time, the Grenville Mountains eroded.

• Rocks remaining from that ancient mountain chain are the oldest rocks that we see exposed at the surface in the Northeast today.

Oh No…Not Again!

• Sometime about 470 million years ago, the ancient Iapetus Ocean began to close as the plate carrying Baltica (proto-Europe) approached the North American plate

• Baltica did not collide with North America until several million years later, but the convergence of the two plates created a whole new look for eastern North America.

• As the continents approached one another, the oceanic crust in the middle was forced under the Baltica plate.

• The friction and melting of the crust from the intense pressure of the colliding plates created a string of volcanic islands along the area where the plates converged (known as the subduction zone).

• Over millions of years, more and more land was added on during collisions. Mountains were built up on the east coast of North America.

• More land continued to add on to North America over time

Chatfield Hollow: Gneiss Rocks Form

It metamorphoses then uplifts

Pangaea Forms

• Africa collides with North America between 360 - 245 million years ago

• Pangaea forms a supercontinent!!!

These collisions resulted in the formation of the supercontinent of Pangaea. Mountain chains form.

Pangaea begins to rift apart

Pangaea Rifts Apart

By around 200 million years ago, rifted apart and set the stage for the development of Africa, North America, and the Atlantic Ocean as we know them

Breaking Up is Hard to do…

• Pangaea breaks up!• Africa pulls away from North America• Rifts form and fill with sediment and lava

Hills and Valleys• After the

crunching and pulling of continents, Connecticut had north-south ridges and valleys.

What happened to New England?

Volcanoes forced out great flows of lava through long cracks in the floor

of the Connecticut Valley.

Tying it all together

The Big Question: What Changed the Surface of the Earth After This?