Plate Tectonics Flashcards
Lithosphere
the solid outer section of Earth, which includes Earth’s crust (the “skin” of rock on the outer layer of planet Earth), as well as the underlying cool, dense, and rigid upper part of the upper mantle. The lithosphere extends from the surface of Earth to a depth of about 44–62 mi (70–100 km).
Asthenosphere
the highly viscous, mechanically weak and ductilely deforming region of the upper mantle of the Earth. It lies below the lithosphere, at depths between approximately 80 and 200 km (50 and 120 miles) below the surface.
Inner Core
the Earth’s innermost part and according to seismological studies, it is primarily a solid ball with a radius of about 1220 kilometers, or 760 miles (about 70% of the Moon’s radius).
Outer Core
the Earth is a liquid layer about 2,300 km (1,400 mi) thick and composed of iron and nickel that lies above Earth’s solid inner core and below its mantle. Its outer boundary lies 2,890 km (1,800 mi) beneath Earth’s surface.
Seismic Waves
waves of energy that travel through the Earth’s layers, and are a result of an earthquake, explosion, or a volcano that gives out low-frequency acoustic energy. Many other natural and anthropogenic sources create low-amplitude waves commonly referred to as ambient vibrations.
Oceanic Crust
the relatively thin part of the earth’s crust that underlies the ocean basins. It is geologically young compared with the continental crust and consists of basaltic rock overlain by sediments.
Continental Crust
the layer of igneous, sedimentary, and metamorphic rocks that forms the continents and the areas of shallow seabed close to their shores, known as continental shelves.
Density
a characteristic property of a substance. The density of a substance is the relationship between the mass of the substance and how much space it takes up (volume). The mass of atoms, their size, and how they are arranged determine the density of a substance.
Wegener
was a German polar researcher, geophysicist and meteorologist. During his lifetime he was primarily known for his achievements in meteorology and as a pioneer of polar research
Continental Drift
the movement of the Earth’s continents relative to each other, thus appearing to “drift” across the ocean bed. The speculation that continents might have ‘drifted’ was first put forward by Abraham Ortelius in 1596.
Convergent Boundary
In plate tectonics, a convergent boundary, also known as a destructive plate boundary (because of subduction), is an actively deforming region where two (or more) tectonic plates or fragments of the lithosphere move toward one another and collide.
Divergent Boundary
In plate tectonics, a divergent boundary or divergent plate boundary (also known as a constructive boundary or an extensional boundary) is a linear feature that exists between two tectonic plates that are moving away from each other.
Transform Boundary
A transform fault or transform boundary, also known as conservative plate boundary since these faults neither create nor destroy lithosphere, is a type of fault whose relative motion is predominantly
Sea-floor Spreading
a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. Seafloor spreading helps explain continental drift in the theory of plate tectonics.
Pangaea
Pangaea or Pangea was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from earlier continental units approximately 300 million years ago, and it began to break apart about 175 million years ago
