GEOL 101 - Chapter 2 Plate Tectonics

A supercontinent, consisting of all of Earth's landmasses, once existed. This supercontinent was called Pangaea and began breaking apart about 200 million years ago.

Consisting of all of Earth's landmasses, once existed.

The supercontinent and began breaking apart about 200 million years ago.

German scientist; Lived in Greenland and died out there with his whole crew; First proposed continental drift hypothesis in 1915; Published The Origin of Continents and Oceans. Did a lot of work research and looked for evidence but didn't have the drive to proof his theory. Therefore, continental drift is just a hypothesis.

Earth's strong, outer layer. Effectively detached from the asthenosphere because of the physical properties. The rigid outer layer of the Earth that contains the Curst and Upper Mantle.

A hotter, weaker region of the mantle under the lithosphere. The plastic layer below the lithosphere; composed of only Mantle.

The rigid outer layer of the Earth.

The more plastic layer of rock below the Earth's crust.

The lithosphere is broken into approximately two dozen smaller sections. These plates are in constant motion.

Most interactions among individual plates occur along their boundaries. First established by occurrence of volcanoes and earthquakes. Three types of plate boundaries: divergent, convergent, and transform.

(Constructive margins) plates move apart from each other.

(destructive margins) plates move together toward each other.

(conservative margins) Plates grind past each other without the production or destruction of lithosphere (also called transform fault) Example: San Andreas Fault

Along the crest of the ridge is a canyon-like feature

The mechanism that operates along the ridge to create new ocean floor

An elongated depression, will develop within the region of the divergence.

The leading edge of one plate is bent downward, as it slides beneath the other.

The surface manifestations produced at subduction zones.

Occurs when water from the subducting plate mixes with the hot rocks of the asthenosphere, generating magma.

The resulting volcanic mountain chain.

If the volcanoes emerge as islands

Most join two segments of an oceanic ridge system along breaks in the oceanic crust

a cylindrically shaped upwelling of hot rock

The surface expression of a mantle plume, is an area of volcanism.

As a plate moves over a hot spot, a chain of volcanoes is built.

When the basalt cools below ______ point, about 585C, the magnetite aligns toward the position of the north pole.

The magnetite is then "frozen" in position and indicates the position of the north pole at the time of rock solidification.

Earth's magnetic field periodically reveres polarity - the north pole becomes the south pole, and vice versa

Rocks that exhibit the same magnetism as the present magnetic field

Rocks that exhibit the opposite magnetism

The sequence of shifts in the polarity of Earth's magnetic field, determined from lava flows.

The subduction of cold oceanic lithosphere

Elevated lithosphere on an oceanic ridge will slide down due to gravity.

Located in the mantle, where warm, buoyant rocks rise and cool, dense rocks sink, is the underlying driving force of plate tectonics.

Because geologic evidence supported the existence of tropical swamps in the Northern Hemisphere.

Wave erosion and coastal deposition have changed the shape of the continents.

Most tectonic plates contain both oceanic and continental lithosphere.

Very few plate boundaries follow the edges of continents.

The single ocean that existed after the Pangaean supercontinent formed.

A piece of the Panthalassa Ocean that existed after the Pangaean supercontinent formed.

A supercontinent that began to break apart about 200 million years ago.

Laurasia and Gondwanaland

Gondwanaland

The collision of India with Asia.

Wegener proposed that gravitational forces from the Sun and Moon could move continents.

The Philippine plate

The outermost portion of the mantle.

Faulting Earthquakes Volcanoes Mountain building

Due to tectonic activity, rocks on the ocean floor are continually recycled.

A convergent plate boundary

180 million years

Crust is being destroyed

Crust is being created

Warmer material near the ridge is less dense, so floats higher on the mantle.

East African Rift Valley

True

Younger and warmer plates will have a shadow angle of descent.

Subduction Zone

Deep-ocean trench

True

On the ocean floor offsetting segments of oceanic ridge

True

Distance from the rift and age of seafloor sample

Slab Pull

The jigsaw fit of the continent Mesosaurus fossils found on South American and Africa Matching geologic units in the Appalachian and Caledonian Mountains Major coal fields found in the eastern United States