Plate Tectonics Flashcards
Lithosphere
A lithosphere is the rigid, outermost shell of a terrestrial-type planet or natural satellite that is defined by its rigid mechanical properties
Asthenosphere
The asthenosphere is 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 below the surface
Mesosphere
the region of the earth’s atmosphere above the stratosphere and below the thermosphere, between about 30 and 50 miles (50 and 80 km) in altitude.
Inner Core
The Earth’s inner core is the Earth’s innermost part. It is primarily a solid ball with a radius of about 1,220 kilometres, which is about 70% of the Moon’s radius. It is composed of an iron–nickel alloy and some light elements
Outer Core
The outer core of the Earth is a fluid layer about 2,300 km (1,400 mi) thick and composed of mostly 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
Seismic waves are waves of energy that travel through the Earth’s layers, and are a result of earthquakes, volcanic eruptions, magma movement, large landslides and large man-made explosions that give out low-frequency acoustic energy
Oceanic Crust
The topmost layer, about 500 metres (1,650 feet) thick, includes lavas made of basalt (that is, rock material consisting largely of plagioclase [feldspar] and pyroxene). Oceanic crust differs from continental crust in several ways: it is thinner, denser, younger, and of different chemical composition.
Continental Crust
The continental crust is 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
The density, or more precisely, the volumetric mass density, of a substance is its mass per unit volume. The symbol most often used for density is ρ, although the Latin letter D can also be used.
Alfred Wegener
Alfred Lothar 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
Continental drift is 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, is a region of active deformation where two or more tectonic plates or fragments of the lithosphere are near the end of their life cycle.
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
Transform boundaries are places where plates slide sideways past each other. At transform boundaries lithosphere is neither created nor destroyed. Many transform boundaries are found on the sea floor, where they connect segments of diverging mid-ocean ridges. California’s San Andreas fault is a transform boundary.
Sea-floor Spreading
Seafloor spreading is 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.
