Earth Systems 3209

1. Earth Systems 3209 Reference: Chapters 4, 15, 16, 19; Appendix A & B Unit: 4The Forces Within Earth

2. Unit 4: Topic 2.8 Geology of Newfoundland Focus on . . . • describing the geologic layout of the island of Newfoundland. • Core STSE – “The Geology of Newfoundland and Labrador”

3. Iapetus Ocean North American Plate African Plate Plate Tectonics and Newfoundland • The Geological Formation of Newfoundland • About 500 hundred million years ago, the central portion of North America was under awarm tropical sea called the Iapetus Ocean. Europe, Africa and North America bordered this body of water.

4. Iapetus Ocean North American Plate African Plate Plate Tectonics and Newfoundland • The Geological Formation of Newfoundland • Over the next150 million years (350 million years ago), forces within Earth’s mantle slowlycarried these continents on a collisioncourse. Asthe continents drifted together and collided, the ocean floor (a volcanic island arc) wassqueezed and then pushed upward to form the AppalachianMountains.

5. Plate Tectonics and Newfoundland • The Geological Formation of Newfoundland • The remains of this mountain range now exists throughout central and western Newfoundland and is thenorthern most part of the Appalachians in NorthAmerica. This range, continues through most of the British Islesand into Norway.

6. Ophiolite Complex Tablelands Plate Tectonics and Newfoundland • The Geological Formation of Newfoundland • An area called the Tablelands in GrosMorneNational Park has rocks that were once part of Earth’s mantle but were pushed on top of Earth’scrust during the collisionof the continents 350 millionyears ago. These sightings called Ophiolite complexes, represents an ocean floor profile resting on land and are rarely seen on Earth’s surface.

7. New Divergent Boundary North Americam Plate African Plate Plate Tectonics and Newfoundland • The Geological Formation of Newfoundland • 225 million years ago, the forces in Earth’smantle that brought the continents together reversed and slowly began topull them apart. The divergent boundary responsible for the shifting of the plates rifted within the African plate and caused the plates to drift apart, leaving a small section of the African plate behind.

8. New Divergent Boundary African Plate Left Behind North Americam Plate African Plate Plate Tectonics and Newfoundland • The Geological Formation of Newfoundland • During this process a small bit of Africa got left behind!When you stand on Signal Hill in St. John’s,you are standing on rocks that are identical toones in the country of Morocco in Northern Africa! The Eastern part of Newfoundland was once a part of the African plate.

9. Western Zone Central Mobile Belt Eastern Zone Plate Tectonics and Newfoundland • The Geological Layout of Newfoundland • Western (Humber) Zone: • Has been a part of the North American plate for at least the last billion years. • Central (Zone) Mobile Belt: • Remnants of volcanic island arcs andthe ancient Iapetus ocean floor. • Eastern (Avalon) Zone: • Once part of the African plate which remained attached as Pangaea split200 million years ago.

10. Plate Tectonics and Newfoundland • The Geology of Newfoundland Labrador Site of ophiolite sequence Western (Humber) Platform Central Mobile Belt Eastern (Avalon) Platform

11. Example 1: Which area of the island of Newfoundland is composed of rocks similar to an ancient ocean floor? (A) Eastern (B) Central (C) Southern (D) Western

12. Example 2: When the Proto-Atlantic Ocean closed many years ago, which mountain chain was created on the East coast of North America? (A) Andes Mountains(B) Appalachian Mountains (C) Himalaya Mountains(D) Rocky Mountains

13. Your Turn . . . Take the time and complete the following questions . . .(Solutions to follow) Questions: Use the diagram and your knowledge of the theory of Plate Tectonics to explain how the three geologic zones of the island portion of Newfoundland and Labrador were formed. A B C

14. Solutions . . . Question: Use the diagram and your knowledge of the theory of PlateTectonics to explain how the three geologic zones of theisland portion of Newfoundland and Labrador were formed. Answer:It is thought that the geology of Island Newfoundland resulted long ago when the IapetusOcean was closing. The North American plate collided with the African plate and as a result a portion of the Iapetus Ocean floor was sandwiched in between. Zone“A” is referred to as the Western (Humber) Zone and was part of the North American plate. Zone “C” is referred to as the Eastern (Avalon) zone and is thought to part of the African plate. Zone“B” is referred to as the Central Mobile Belt and is thought to be once part of the ancient Iapetus Ocean. A B C

15. Summary . . . Overview of Points covered: Newfoundland is divided into THREE geologic zones: Western (Humber) Zone Central (Zone) Mobile Belt Eastern (Avalon) Zone Note: Newfoundland formed as a result of plate tectonic activity over the past 500 million years. This activity formed the Appalachian Mountains and left a part of the African Plate behind as part of Eastern Newfoundland.