CH 25 and CH 26 Flashcards
a system of mountain ranges on the seafloor separated by valleys
mid-range ridge
a long narrow depression forms in between peaks along mid-range ocean ridge
rift valley
the boundary where two plates collide
convergent plate boundary
when a thick and boundary continental plate meets a thin and dense oceanic plate the denser plate dives beneath the continent in a process
subduction
the boundary between two plates that are moving apart
divergent plate boundary
this type of boundary where plates slide horizontally past each other in opposite directions
transform plate boundary
a sudden movement or vibration of the ground that occurs when rocks slip and slide along enormous cracks in Earths crust called faults
earthquake
a crack in Earths crust along which rock has moved
fault
this sudden release of strain energy as rock moves along a faults
elastic rebound
the point of origin of an earthquake
focus
the point on Earths surface directly above the focus
epicenter
who came up the Continental drift hypothesis
Alfredo Wegener
what are some evidence for the Continental drift hypothesis
- the continents matched up like a puzzle piece
- Mountain ranges with the same rock type
- found large animals fossils
what was the name of the super Continental
Pangaea pangaea
who came up with the seafloor spreading hypothesis
Harry Hess
how did Harry Hess discover the seafloor spreading
He used sonar
who discovered the MOR
Harry Hess
on the ocean floor where is the newer rock formed
closer to the MOR
what are the 3 plate boundaries
- Divergent plate boundary
- Convergent plate boundary
- Transform plate boundary
how do convergent plates move`
they collide together
subduction only happens with what type of plate boundary
convergent plate boundary
what types of crust do we have?
Continental crust and Oceanic crust
what type of crust has to be present for volcanic activity to occur
oceanic crust
if two Continental crust collide what will happen
a mountain will be made
if oceanic and continental crusts converge what two land forms will be created
deep sea trench and volcanoes
what can be created when two oceanic crusts converge
a oceanic island and maybe deep sea trench
what do hot spots create
volcanic islands
how do divergent boundaries move
they move away from each other
what is an example of a divergent plate boundary
MOR(only oceanic crust) and East African Rift(only continental)
how do transform plate boundaries move
they slide past each other
what is an example of a transform plate boundary
San Andres fault
what type of crusts are involved with transform plate boundaries
only continential
what is a convection current
- magma heats up,becomes less dense, and rises
2. magma cools, becomes more dense, and sinks
what is a fault
a crack in earth surface
which plate boundaries have shallow earthquakes
divergent and transform plate boundaries
which plate boundaries have deeper earthquake
convergent plate boundary
what are the four types of stress applied to rock
compression, tension, shear, and torsion stress
what are the two types of deformation
elastic and plastic deformation
what happens during elastic deformation
when the stress is removed it returns to its original state
what happens during plastic deformation
when stress is removed it remains in that new shape
how many type of seismic waves are there
3 types primary, secondary, and surface waves
what are the two types of body waves
primary and secondary waves
what type of wave is a primary wave
a compression wave
which body wave moves the fastest
primary wave
what type of materials do p waves travel through
solids and liquids
what type wave is a secondary wave
transverses
what type of material do secondary waves travel through
only solids
what type of waves do the most damage
surface waves
what are the two scales to measure earthquakes
Richter scale and the Mercalli scale
what does the Richter scale measure
the amount of energy released
what does the Mercalli scale measure
the amount of damage
a mineral is , , ,
natural occurring, inorganic solid, crystalline form
what are the 2 abundant elements that make up earths crust?
oxygen and silicon
what does inorganic mean?
materials that are non living
what does the arrangement of an atom and the bonds between them reflect about a mineral?
breaks,how hard it is, and kind of crystal shape
what are all the ways to identify minerals?
luster, streak, hardness, crystal shape, fracture, cleavage, atomic arrangement
what are the two types of luster?
metallic and nonmetallic
how does metallic luster reflect light?
very easily like a metal surface
how does nonmetallic luster reflect light?
glassy look doesn’t reflect easily
how do you perform a streak test?
rub a mineral on an unglazed porcelain tile
what are the two types of breakage that can happen to minerals?
cleavage and fracture
what is the name of the scale to measure the hardness of a mineral?
Mohs Scale of Hardness
what is the number range on Mohs scale of hardness?
1-10
how many different crystal shapes are there?
6
minerals grow from the_______
inside out
what are the three ways minerals can form?
hot water, molten rock and evaporation
what are the 2 mineral groups?
silicates and nonsilicates
which mineral group is the most abundant in Earths crust?
silicate minerals
what elements are silicates made of?
silicon and oxygen
Nonsilicates do not contain what element?
silicon
what mineral is used to make glass?
quarts
