geology 4 Flashcards
what is the inner core made of
solid nickel and iron
what is the outer core made of
liquid, iron
what is the mantle made of
iron-rich rock
semi-solid
top of mantle called the asthenosphere
what is the evidence that there was once a super continent
fit of continents
mountain chains and rock types
volcanoes and earthquake locations
glacial evidence
what are the two plate types
oceanic plates-made of basalt, dense
continental plates-made of granite, less dense
how do plates move
convection currents in the mantle
move very slowly
are constantly in motion
what are the 4 types of plate motions
converge-compression of plates
diverge-tension(pull apart)
transform-slide past eachother
subduction-ocean plate is pushed under crust
what is a hot spot
volcanoes that occur in the middle of a plate
no plate boundaries
plate moves-hot spots don’t
what is an earthquake
ground motion caused by a geological event
energy is transferred through the earths crust
what are the three types of earthquake waves and their characteristics
p-waves- primary waves,compression waves, move very fast
s-waves-secondary, shear waves, move slower than p-waves, do not travel through liquids
l-waves-slowest waves, most damaging, rolling motion, side to side motion
what is the epicenter and focus
epicenter-place on earths surface directly above the focus
focus-where the actual break occurs
what are the energy and ground displacement
energy released increases 32x(5 magnitude is 32x more energy than a 4)
ground displacement increases 10x (5 moves the ground 10x more than a 4)
what are the three ways to measure earthquake magnitude
richter scale-older system, not accurate for earthquakes far away from seismograph station
moment magnitude scale-more accurate at long distances
mercalli scale-measured by observation
what are primary effects of earthquakes
ground shaking
ground rupture
liquefaction
what are secondary effects of earthquakes
structure collapse
fires
flooding
starvation and disease
what is relative and absolute time
relative-compares rocks or fossils to one another based on logical rules
absolute-actual age of rock or fossil in years ago
what is instability and 3 examples of elements becoming stable
radioactive elements are unstable
uranium-238->lead-206
carbon-14->nitrogen-14
potassium-40-> argon-40
three forms of radioactive decay and what each changes
alpha decay-atomic number -2 and mass-4
beta decay-atomic number +1
electron capture- atomic number -1
what is a half life
amount of time it takes for half of the radioactive element or parent element to decay into stable daughter products
what are the 6 geologic principles
uniformitarianism-present is the key to the past
superposition-the oldest rocks are at the bottom, youngest at top
cross-cutting relationships-object being cut is older than the object doing the cutting
original horizontality-rocks are deposited flat
inclusions-older than surrounding rock
uncomformities-erosion, folding and erosion, different rock types
what is sea level rise
fine upward, fine/coarse
what is sea level fall
coarsen upward, coarse/fine
what is correlation
matches rocks across distances
use age/fossil data
uses stacks of rocks
