plate tectonics & GTS Flashcards
what layers are the earth divided into from the surface?
crust, mantle, lithosphere, asthenosphere, core
crust
solid, low density, brittle, forms the continents adn ocean floor
mantle
consists of hot, dense, semi-solid rock, broken into layers
lithosphere
upper part of the mantle plus crust, is cooler and more solid than lower sections
asthenosphere
softer, mobile zone in the mantle that lithosphere floats on
core
outer - liquid
inner - solid
as the earth rotates, the liquid core spins, and does what?
creating the earth’s magnetic field
what are the driving force behind plate movement
convection currents
how are convection currents formed
as liquid part of the mantle heats from radioactive decay in core, and rises then cools and sinks
divergent plate boundaries
magma surging upward to the surface pushes two plates apart creating new crust as it cools and spreads
ex: ridges, volcanic activity, earthquakes
Mid Atlantic ridge, african rift valley
convergent plate boundaries
when two plates collide; trenches, volcanic arcs, earthquakes
ex: Mariana’s trench
subduction occurs when
one plate slides under another, which usually occurs when denser oceanic crust slides underneath a lighter continental plate underneath forming a trench.
The subducted crust heats to magma.
Magma may erupt as volcanoes near plate boundary
equal density
both oceanic or continental; mountain ranges
ex: Himalayas (2 conti) & Japan (2 ocean)
Transform
the boundary between two plates sliding past one another; earthquakes and faults
ex: San Andreas fault
topography
earth’s landforms
tectonics builds _____which creates ______ and that shapes _____ by ____,____,___
mountains, topography, climate, altering patterns of rain, wind, currents, heating, cooling, thereby affecting the locations of biomes, influencing where animals & plants live
what is the focus of an earthquake
point of rock fracture
where is the focus always
underground
what is the place on the surface directly above ground
epicenter
a tsunami occurs after an?
earthquake or volcano displaces a large volume of water
hot spots
stationary mantle plumes deep within asthenosphere is molten rock which rises and melts through the lithospheric plate forming a large volcanic mass at a hot spot
global dimming
a decrease in the amount of sunlight reaching the surface of the earth, believed to be caused by pollution in the atmosphere
what is an earthquake and how is it caused
sudden shaking of the ground and occurs when stress overcomes a locked fault, releasing stored energy.
