TeCtonICS & Internal Earth Processes Flashcards
What is the Crust composed of? How deep does it go?
Basalt and granite. … 0-35km
what is the Mohorovicic discontinuity?
Moho is 30-70km below continental crust, 6-8 km below oceanic crust, separates mantle and crust
What is the mantle composed of ?
peridotite and eclogite; 35- 2,890 km; 100-3,500 degrees C. Convention cycles this material
What is the core composed of? how deep?
2,890- 6,378km , liquid outer, solid inner. nickel and iron
What are the different sublayers of the planet?
lithosphere - 0-60km. cooling layer of the planet’s convection cycle solidifies over time. Continental = plates, oceanic = mafic basalt and is generally thicket
asthenosphere- 100-700km w/in mantle, uppermost later. heat and pressure keep it soft and plastic like
mesosphere 900-2,800km, lower part of mantle to mantle-core boundary
What is ridge- push tectonic motion?
low density material from mantle rises up to oceanic ridges, causing higher elevation as plates slide downward and away due to force of gravity
slab-pull tectonics? how does trench suction friction work into this?
cold, heavy plates that have moved away from oceanic ridge slide underneath/ back into mantle, providing fuel for convection
trench suction pulls plates downward into subduction zones due to mantle convection currents
convergent plate boundaries are ___ and form __, __, and ____
destructive; mid-atlantic mountain ranges, oceanic trenches, or an oceanic trench and a coastal mountain
oceanic crust is ______ and therefore ________ more of the mantle.
continental crust is ______ and _______ and therefore ________ into mantle and _______ above earth’s surface
denser; displaces ; than continental crust of same thickness
less dense and thicker; extends deeper; higher
divergent boundaries causes ______ in oceanic crust and _____ in continental crust
sea floor spreading and ridges; rift valleys
earthquakes are caused when:
the San Andreas Fault is an example of a ____ transform plate boundary:
friction occurs during transform plate movement. one plate gets “stuck” and when it is released, the potential energy that was stored up is released as seismic waves.
strike-slip
Define the three types of geologic faults:
normal: Hanging wall moves downward relative to footwall
reverse: footwall moves downward relative to hanging wall
strike slip: virtually no vertical movement
what is orogenesis?
mountain creation
what are the four types of orogenesis?
folded mountains: occur at convergent plate boundaries and form as long chains due to long term deformation and metamorphosis of igneous and sedimentary rock j
fault block- occur at normal or reverse faults where a large portion of crust is displaced
oceanic ridges: occur at divergent plate boundaries
volcanic: occur singly due to volcanic formation over time
what are the 3 main types of rocks in the rock cycle and how do they transform into one another?
sedimentary: erosion and weathering causing compact sections to break into sediments which over time compact into solid sections. HEAT and PRESSURE will turn these into….
Metamorphic rock: erosion/ weathering will also turn this into sediments. melting will turn these into magma , which after cooling forms
IGNEOUS ROCK: heat and pressure will revert this back to metamorphic, while erosion/ weathering turns this into sediments. melting turns it back into magma
