tectonics 1.1 Flashcards
tectonic theories and boundaries
what does the lithosphere consist of?
crust and uppermost mantle
what is the internal structure of the earth?
earth has a layered structure consisting of the core, mantle and crust
what is the asthenosphere?
mantle below lithosphere.
what happens in divergent plate boundaries
where plates move away from each other
What happens in convergent plate boundaries?
where plates move towards each other
transform plate boundary
where plates slide past each other
what does the plate tectonic theory state?
-earth has a three layered structure(cm2c)
-earth’s lithosphere is broken up into huge pieces called tectonic plates
-plate movements result in formation of land forms for examples oceanic trenches and mountain ranges and phenomena like earthquakes and tsunami.
where is the position of the core
inner most
where is the position of the mantle
between the core and crust
where is the position of mantle
outermost
what is the temperature range for core
4400-6000 degrees
temperature of mantle
1000-3700 degree
temperature of crust
lowest
thickness of core
thickest at 3300km
thickness of mantle
2900km
thickness of crust
thinnest, 3-70 km
what are the two forces responsible
convection current and slab pull force
process of convection current
-heat from earth’s core causes mantle to become less dense
-it then rises towards surface.
-rising convection current spreads he plates and drag them apart causing plate movement
-mantle material then loses heat and sinks towards core.
-material gets heated up again and process repeats.
process of slab pull force
-when 2 plates converge, the denser oceanic crust is pulled down by gravity as it subducts beneath less dense crust.
-denser oceanic crust sinks deeper into the mantle under its own weight, pulling the rest of the plate with it, contributing to further convergence.
6 major tectonic plates
african antartic eurasian, north american, south american. india australia
two types of crust and its characteristics
continental crust
-makes up land masses
-light granite rocks
-less dense
oceanic crust
-makes up sea floor
-heavy basaltic rocks
-more dense
major continental plates
south america
north america
australian
african
eurasian
major oceanic plates
pacific
philippine
nazca
