Plate Tectonics and the Ocean Floor

These flashcards cover key vocabulary and concepts related to plate tectonics and ocean floor geology for exam preparation.

Plate tectonics

A theory explaining the structure of the Earth's lithosphere, where tectonic plates move and cause geological phenomena.

Continental drift

The theory that continents have moved over geological time and were once joined as a supercontinent.

Pangea

The name of the supercontinent that existed around 335 million years ago, before breaking apart into the current continents.

Glossopteris

A fossil fern with large seeds used as evidence for continental drift, found across southern hemisphere landmasses.

Paleomagnetism

The study of the record of the Earth's magnetic field in rocks, used to support the theory of plate tectonics.

Divergent boundary

A tectonic plate boundary where plates move away from each other, leading to the formation of new crust.

Convergent boundary

A tectonic plate boundary where plates collide, leading to subduction or mountain formation.

Transform boundary

A tectonic plate boundary where plates slide past one another horizontally, causing earthquakes.

Slab pull

A force driving the movement of tectonic plates where the denser oceanic plate sinks into the mantle during subduction.

Active margin

A coastal area where tectonic plates meet, characterized by high seismic activity and volcanism.

Passive margin

A coastal area that is not a plate boundary, characterized by thick sediment deposits and minimal tectonic activity.

Asthenosphere

The semi-fluid layer beneath the lithosphere that allows tectonic plates to move.

Sea floor spreading

The process by which new oceanic crust is created at mid-ocean ridges as tectonic plates pull apart.

Benioff zone

A plane of earthquakes that occur in a subduction zone, identified by the dipping pattern of the earthquakes.

Fossil evidence

Remains or traces of ancient plants and animals used to infer past geological conditions and support continental drift.

Continental crust

The layer of igneous, sedimentary, and metamorphic rocks that forms the continents, generally less dense than oceanic crust.