Unit 4 Flashcards
Core
the innermost zone of Earth’s interior, composed mostly of iron and nickel; it includes a liquid outer layer and a solid inner layer
Mantle
the layer of Earth above the core, containing magma, the asthenosphere, and the solid upper mantle
Magma
molen rock
Asthenosphere
the layer of Earth located in the outer part of the mantle, composed of semi-molten rock
Lithosphere
the outermost layer of Earth, including the solid upper mantle and crust
Plate tectonics
the theory that the lithosphere of Earth is divided into plates, most of which are in constant motion
Earthquake
a sudden movement of Earth’s crust caused by a release of potential energy from the movement of tectonic plates
Hot spot
in geology, a place where molten material from Earth’s mantle reaches the lithosphere
Volcano
a vent in the surface of Earth that emits, ash, gasses or molten lava
Divergent
an area below the ocean where tectonic plates move away from each other
Seafloor spreading
caused by a divergent boundary, in which rising magma forms new oceanic crust on the seafloor at the boundaries between those plates
Convergent boundary
an area where one plate moves toward another plate and collides
Subduction
the process in which the edge of an oceanic plate moves downward beneath the continental plate and is pushed toward the center of earth
Island arc
a chain or islands formed by volcanoes as a result of two tectonic plates coming together and experiencing subduction
Collision zone
an area where two continental plates are pushed together and the colliding forces push up the crust to form a mountain range
Transform boundary
an area where tectonic plates move sideways past each other
Fault
a fracture in rock caused by a movement of Earth’s crust
Igneous rock
rock formed directly from magma
Sedimentary rock
rock that forms when sediments such as muds, sand, or gravels are compressed by overlying sediments
Metamorphic rock
rock that forms when sedimentary rock, igneous rock, or other metamorphic rock is subjected to high temperature and pressure
Rock cycle
the geologic cycle governing the constant formation, alteration, and destruction of rock material that results from tectonics, weather, and erosion, among other processes
Physical weathering
the mechanical breakdown of rocks and minerals
Chemical weathering
the breakdown of rocks and minerals by chemical reactions, the dissolving of chemical elements from rocks, or both these processes
Acid precipitation
precipitation high in sulfuric acid and nitric acid (acid rain)