Plate Tectonics Flashcards

Flashcards on Plate Tectonics

Lithosphere

The rocky outer part of the Earth, including the crust and the uppermost part of the mantle.

Plates

Tectonic, or lithospheric, plates that each move independently of each other.

Alfred Wegener

Astronomer and meteorologist who proposed the idea of Pangaea in 1912 and backed it up with evidence.

Pangaea

A single supercontinent meaning all Earth in Greek that existed approximately two twenty five to three hundred million years ago.

Continental Drift

The process by which Pangaea broke apart and eventually led to the landmass distribution we have now.

Bruce Heesen and Marie Tharp

Geologists who published the first physiographic map showing the physical features of the Atlantic Ocean floor in 1957.

Continuous echo sounder

A type of sonar device used to collect bathymetric soundings, which are different depth measurements.

Mid-Atlantic Ridge

A vast Mid-Atlantic mountain spine crisscrossed by huge fracture lines.

Deep Trenches

Deepest feature on the planet.

Harry Hess

A geologist who proposed that magma spills out from the fracture lines of the mid-oceanic ridges.

Seafloor as a Giant Conveyor Belt

New seafloor is formed on either side of the ridges as magma flowed out and pushed away the old seafloor.

Robert Dietz

Geologist and oceanographer who published a similar idea called the spreading seafloor theory in 1961.

Fred Vine and Drummond Mathews

Geologists and geophysicists who published evidence recorded in the seafloor itself in 1963, related to Earth's paleomagnetism.

Earth's Paleomagnetism

The Earth's magnetic field reverses periodically and this is recorded in rocks that contain iron.

Magnetic Barcode

A magnetic barcode of black and white stripes that mark where polarity changed, arranged symmetrically around the ridge.

Age of Basalt Rock

Determining the age of a basalt rock in the seafloor confirmed the matching patterns of magnetic histories.

Subduction

A process where a thick slab of Pacific Ocean floor is pushed under the edge of a different slab of Earth's crust and consumed into the mantle.

Subduction Zone

Because the oceanic crust has a greater density than the continental crust, the thinner, denser oceanic plate dives beneath the lighter, thicker, and more buoyant continental crust. This forms a subduction zone.

Pacific Ring Of Fire/Circum Pacific Belt

An area surrounding the basin of the Pacific Ocean where approximately 75% of all volcanoes are dotted around it, and 90% of earthquakes occur along its path.

East Pacific Rise

A divergent plate boundary, or place where plates are moving away from each other.

Divergent Plate Boundary

Place where plates are moving away from each other.

Peru-Chile Trench

The denser oceanic Nazca plate collides with and is pulled beneath the lighter continental South American plate, creating a convergent plate boundary.

Andes

Plates colliding along a convergent plate boundary and have many volcanoes.

San Andreas Fault

Where the North American plate moving roughly Southwest is sliding horizontally past the Pacific plate moving Northwest.

Transform Boundary

Where the plates touch they can get stuck and stress builds up as the rest of the plate continues to move. This stress causes the rocks to break, suddenly lurching the plates forward and causing earthquakes.

Continental Plates Convergence

The collision compresses the crust folding and pushing up huge mountain ranges.

Himalayas

Sit where the Indian plate is converging with the Eurasian plate.

Continents Growth

Continents grow from a nucleus of ancient and stable igneous and metamorphic rocks.

Continental Shield

Where these rocks are exposed at the surface.

Plate Motion Detection

Plate motion is detected by satellites which record changes in Earth's surface.