connecticut’s geological history. marble & quartzite schist sandstone & basalt schist

Connecticut’s Geological History

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Marble & Quartzite

SchistSandstone & Basalt

SchistGneiss

Simplified Geology of Connecticut

Which type of rock is NOT likely to be naturally found in Avon, CT?

1) Schist

2) Basalt

3) Marble

4) Sandstone

5) All of these are likely to be in Avon, CT

Which type of rock is NOT likely to be naturally found in Avon, CT?

1) Schist

2) Basalt

3) Marble

4) Sandstone

5) All of these are likely to be in Avon, CT

Given the CT geology map info, which of the following statements is accurate?

1) CT is mostly composed of sedimentary rock.

2) CT was never located near a major plate boundary.

3) All of the rock of CT formed at the same time.

4) CT experienced a shield volcano lava flow.

5) None of these are accurate.

Given the CT geology map info, which of the following statements is accurate?

1) CT is mostly composed of sedimentary rock.

2) CT was never located near a major plate boundary.

3) All of the rock of CT formed at the same time.

4) CT experienced a shield volcano lava flow.

5) None of these are accurate.

The oldest rocks in CT are located in the section called ‘Proto North America’ (PNA).

Given the rocks in PNA today, what rocks were present prior to their metamorphism?

1) Sandstone and Basalt

2) Granite and Limestone

3) Granite and Basalt

4) Limestone and Sandstone

The oldest rocks in CT are located in the section called ‘Proto North America’ (PNA).

Given the rocks in PNA today, what rocks were present prior to their metamorphism?

1) Sandstone and Basalt

2) Granite and Limestone

3) Granite and Basalt

4) Limestone and Sandstone

Which of the following best explains how the parent rocks in PNA formed?

1) It was a glacial lake

2) It was a beach

3) It had fast moving rivers

4) It was magma that cooled underground

5) None of these are reasonable

Which of the following best explains how the parent rocks in PNA formed?

1) It was a glacial lake

2) It was a beach

3) It had fast moving rivers

4) It was magma that cooled underground

5) None of these are reasonable

• Ocean waves wash the sands from rivers together to form a beach coastline. This allows the sandstone to form over time.

• The marine coastal environment is where many shellfish live and die. When they die, the shells collect at the bottom and form into limestone.

There are two sections of ‘Iapetos’ in CT. Both have the same rock type and origin.

Which of the following best describes that origin?1) They were ocean crust and marine sediments that

were crunched together in a convergent plate boundary

2) They were formed by large lava flows3) They were mountains that wore down into sediments

that later compacted and cemented together.4) They were formed by a transform plate boundary

There are two sections of ‘Iapetos’ in CT. Both have the same rock type and origin.

Which of the following best describes that origin?1) They were ocean crust and marine sediments that

were crunched together in a convergent plate boundary

2) They were formed by large lava flows3) They were mountains that wore down into sediments

that later compacted and cemented together.4) They were formed by a transform plate boundary

The rocks of ‘Avalonia’ used to be an Island arc off the coast of Africa.

What rock type were they made up of before they went through metamorphism?

1) Basalt2) Sandstone3) Quartzite4) Granite

The rocks of ‘Avalonia’ used to be an Island arc off the coast of Africa.

What rock type were they made up of before they went through metamorphism?

1) Basalt2) Sandstone3) Quartzite4) Granite

Given that Avalonia was composed of Granite, what does it tell us about its origin?

1) It was likely a subduction volcano island group

2) It was likely a divergent plate volcano island group

3) It formed by continent-continent convergence

4) It formed because of transform plates

Given that Avalonia was composed of Granite, what does it tell us about its origin?

1) It was likely a subduction volcano island group

2) It was likely a divergent plate volcano island group

3) It formed by continent-continent convergence

4) It formed because of transform plates

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What caused the rocks in PNA, Iapetos & Avalonia to go through Metamorphism?

1) North America collided with Africa forming Pangaea

2) The rocks were buried by sediments overtime which caused them to change

3) The rocks were all changed by weathering and erosion over time

What caused the rocks in PNA, Iapetos & Avalonia to go through Metamorphism?

1) North America collided with Africa forming Pangaea

2) The rocks were buried by sediments overtime which caused them to change

3) The rocks were all changed by weathering and erosion over time

Why didn’t the rocks in the Newark Terrane go through Metamorphism?

1) It is made up of rocks that are resistant to acid weathering

2) It is made up of rocks that are very strong and resisted the continent collision.

3) The rocks did not form until after Pangaea.

4) The rocks did not form until after the last ice age.

Why didn’t the rocks in the Newark Terrane go through Metamorphism?

1) It is made up of rocks that are resistant to acid weathering

2) It is made up of rocks that are very strong and resisted the continent collision.

3) The rocks did not form until after Pangaea.

4) The rocks did not form until after the last ice age.

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How did Pangaea break up?

1) The drummer died of a drug overdose and the rest of the band members went their separate ways

2) Transform Plates3) Convergent Plates4) Divergent Plates

How did Pangaea break up?

1) The drummer died of a drug overdose and the rest of the band members went their separate ways

2) Transform Plates3) Convergent Plates4) Divergent Plates

When Pangaea split up, it did so at a divergent plate boundary. When plates

begin to diverge, it is not always in a neat line (think of it more like cracking and

breaking an egg)

The main boundary formed where the Atlantic Ocean is today. But one of the side

cracks in the initially forming boundary happened in which part of CT?

1) PNA

2) Iapetos

3) Avalonia

The main boundary formed where the Atlantic Ocean is today. But one of the side

cracks in the initially forming boundary happened in which part of CT?

1) PNA

2) Iapetos

3) Avalonia

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But why does the Newark Terrane have features like Talcott Mountain

(large cliff to the west and a gradual slope to the east)?

1) It experienced a major fault on the western side which cause the west to drop down and the east to rise up

2) It experienced a major fault on the eastern side which cause the east to drop down and the west to rise up

But why does the Newark Terrane have features like Talcott Mountain

(large cliff to the west and a gradual slope to the east)?

1) It experienced a major fault on the western side which cause the west to drop down and the east to rise up

2) It experienced a major fault on the eastern side which cause the east to drop down and the west to rise up

Farmers have noticed that the soil in CT is rather rocky. In the 1800’s many farmers would dig out the rocks from their fields and use them to make

stone walls around their land.

This was possible due to…1) Weathering of the sandstone 2) Deposition of glacial till3) Metamorphism of the ocean rock4) Deposition of glacial lake sediments

The geological history of CT in 4 Steps (in Sequence from oldest to most recent) is…

1) Crack, Crunch, Tilt, Scrape

2) Crunch, Tilt, Scrape, Crack

3) Crunch, Scrape, Tilt, Crack

4) Crunch, Crack, Tilt, Scrape

5) None of these

CT’s Geologic History1) Crunch—Pangaea formed

2) Crack—Divergent plate boundary began to form in the middle of CT. This was followed by sediments eroding off of the higher elevation points to the east and west.

3) Tilt—The eastern border fault caused the eastern half of the Newark Terrane to sink down.

4) Scrape—Glaciers modified the surface rock and then deposited sediments as they melt