The hypothesis that states that the continents once formed a single land mass, broke up, and drifted to their present locations
Continental Drift
The theory that explains how large pieces of the lithosphere, called plates, move and change shape
Plate Tectonics
A chain of volcanic islands
Island Arc
The solid, outer layer of Earth that consists of the crust and the rigid upper part of the mantle
Proposed that the valley at the center of the ridge crack, or in Earth's crust
The solid, plastic layer of the mantle, made of the mantle rock that flows very slowly, which allows tectonic plates to move on top of it
A long, undersea mountain chain that has a steep, narrow valley at its center, that forms as magma rises from the asthenosphere and that creates new oceanic lithosphere as tectonic plates move apart
Mid Ocean Ridge
The process by which new oceanic lithosphere forms as magma rises to Earth's surface and solidifies at a mid ocean ridge
Sea Floor Spreading
The study of the alignment of magnetic minerals in a rock
Dense, and is made of rock that is rich in iron and magnesium
Oceanic Crust
Low density and rich in silica
Continental Crust
A zone of active volcanoes that encircles the pacific ocean
Pacific Ring Of Fire
A vent or fissure in the Earth's surface through which magma and gases are expelled
When tectonic plates move, sudden shifts can occur along their boundaries
The boundary between tectonic plates that are moving away from each other
Divergent boundary
The boundary between tectonic plates that are colliding
Convergent Boundary
The region along a plate boundary where one plate moves under another plate
Subduction zone
The movement of heated material due to differences in density that are caused by differences in temperatures
A super continent
Wegner hypothesized that the continents once formed part of a single land mass.... This is called ....