plate tectonics Flashcards
the idea that the earth’s crust and upper mantle are broken into sections called plates that move around on the mantle
theory of plate tectonics
how are plates driven?
by gravity and by cooling of earth (convection)
tectonic plates are also called
lithospheric plates
how thicc are tectonic plates?
100km
the earth once had a single land mass called PANGAEA that broke apart into pieces that drifted away to become major continents
theory of continental drift
nejej
hdejeh
largest geological features on the planet that is resulted by an oceanic divergent plate boundary
mid ocean ridge
mostly underwater mountain range in the atlantic ocean
The Mid-Atlantic Ridge (MAR)
Continental Divergent plate boundary
rift valley
volcanic island arcs, trenches & earthquakes occur when older ocean plate subducts a younger ocean plate. Ex. Mariana Trench
ocean-ocean convergent boundary
Mountains, Volcanoes, and Earthquakes occur. The oceanic plate melts; less dense magma rises to form volcanoes Ex: Andes, Cascade Range, Sierra Nevada
Ocean-Continent Convergent boundary
Mountains form and earthquakes occur. Ex: Himalayas and Alps
Continent-Continent Convergent boundary
San Andreas Fault in California
Strike-Slip Fault or Transform Fault
bending, tilting, and breaking of the Earth’s crust. Its major cause is plate tectonics
deformation
force per unit area applied on the rock
stress
change in shape or volume of the rock that experienced stress
strain
Three kinds of strain
compressional ➡️⬅️, tensional⬅️➡️, shear⬆️⬇️
when a rock experiences stress and does not break
folding
a fold that is convex up and has its oldest beds at its core
anticline
a simple bend in the rock layers so that they are no longer horizontal
monocline
a concave fold with younger layers closer to the center of the structure
syncline
when the rock experiences stress and breaks
fault
the side that is above the fault plane
hanging wall ↘️
the block which would be under the feet of a person standing in a tunnel on the fault plane
↖️foot wall
when the hanging wall moves down ⬅️➡️
normal fault
when the hanging wall moves up ➡️⬅️
reverse fault
a low angle REVERSE fault is called a
thrust fault
where do earthquakes happen
at or near the boundaries between earth’s tectonic plates.
occurs when rock below the earth’s surface moves abruptly
earthquake
