Chapter 3: Physical Geography: landforms

mineral
a particular chemical combination that has a hardness, density, and definite crystal structure of its own
Igneous rocks
formed by the cooling and solidification of molten rock
Sedimentary rocks
composed of particles of gravel, sand, silt, and clay that were eroded from already existing rocks
Metamorphic rocks
formed from igneous and sedimentary rocks by earth forces that generate heat, pressure, or chemical reaction
continental drift
a theory that all landmasses were once united in one supercontinent and over many millions of years the continents broke away from each other, slowly drifting to their current positions
plate tectonics
asthenosphere
a partially molten layer above their earth’s interior
lithosphere
a strong solid shell of rocks
faults
fractures in rock along which there has been movement
subduction
when lithospheric plates collide, the denser, oceanic crust is usually forced beneath the lighter continental material
diastrophism
the great pressure acting on the plates that deforms them by folding, twisting, warping, breaking, or compressing rock.
warping
a result of the changing weight of a large region
fold
a bend or wrinkle in a rock resulting from compression and formed when the rock was in a plastic state
tsunami
sea waves generated when an earthquake, eruption, or underwater landslide abruptly moves the seabed, jolting the waters above
gradational processes
the processes of weathering gravity transfer, and erosion that are responsible for the reduction of the land surface
weathering
the mechanical and chemical processes that fragment and decompose rock materials
mechanical weathering
the physical disintegration of earth materials, commonly by frost action, root action, or the development of salt crystals
chemical weathering
the decomposition of earth materials because of chemical reactions that include oxidation, hydration, and carbonation
mass movement
the downslope movement of earth materials due to gravity
erosional agents
the forces of wind, moving water, glaciers, waves, and ocean currents that carve, wear away, and remove rock and soil particles
floodplains
a valley area bordering a stream that is subject to inundation by flooding
alluvium
the sediment carried by a stream and deposited in a floodplains or delta
water table
the upper limit of the saturated zone and therefore of groundwater; the top of the water within an aquifer
karst topography
a limestone region marked by sinkholes, caverns, and underground streams
glacier
a huge mass of slowly moving land ice
permafrost
permanently frozen subsoil
loess
a deposit of wind blown silt
Categories: Physical Geography