tectonic stuff Flashcards
asthenosphere
region of extremely high pressure beneath lithosphere. Rocks are deformed by enormous stresses. lies depth 100-350km
compression
form of stress produced by action of equal and opposite forces. effect- reduce length of material
continental drift
theory- earth’s continents once different then are today- landmasses were once all joined and then seperated to present locations
convergence
tectonic process where plates move toward each other -associated with subduction, convergence typically occurs in ocean, creating oceanic trench- one of three ways plates interact
core
centre of earth- 16% of volume- 23% of mass- made primarily iron and another lighter element- solid inner core radius 760 miles- liquid outer core 1,750 miles
crust
uppermost division of solid earth- representing less than 1% volume + depth 5-60km- mantle is below
divergence
tectonic process plates move away from each other- results in seperation of plates- associated with seafloor spreading or formation of rift valleys- one of three ways plates interact
epeirogenesis
one of two principal forms of tectonism (other is orogenesis)- epeirogenesis takes form of either uplift of subsidence
fault
an area fracturing between rocks resulting from stress
fold
an area of rock that has been bent by stress
geophysics
branch of earth sciences- combines aspects of geology and physics- addresses planet’s processes as well as its gravitational, magnetic, and electric properties, and means by which energy is transmitted through its interior.
historical geology
study of earth’s physical history- one of two principal branches of geology- other being transmitted through its interior.
Lithosphere
upper layer of Earth’s interior- including crust and brittle portion at top of mantle
MA
abbreviation- means million years- e.g 160 Ma=160 million years
mantle
thick dense layer of rock 2,300 km thick between earth’s crust and core
