First Exam Flashcards
Why is there no old mid Atlantic crust?
It’s dense then subducts
2 types of geologic change
Uniformitarianism (slow gradual- mountains) “present is the key to the past”
Catastrophism (sudden- earthquake)
Know three places on map and plate boundaries
Convergent- Himalayas
Divergent- Mid Atlantic range
Transform- San Andreas Fault
Hot spots/ Magma plumes?
Plume of magma rises from the mantle
Examples- Hawaii, yellow stone national park
3 types of rock (“rock cycle”)
Igneous “first rocks”
Sedimentary “fossils”
Metamorphic “never melting”
Igneous rock
“First rock”
Formed from cool magma
Sedimentary
“Fossils”- Are all sedimentary rocks
Sediment builds up, compacts, pressurized to become rock.
Metamorphic
“Never melting”
Starts off as different type of rock, changes.
Scientific method
Observation Hypothesis Prediction Experiment Theory- hypothesis with some evidence Law- theory backed by evidence becomes law
How old is the earth?
4.5 billion years old
How do we know the earth is that old?
Radiometric dating
Radiometric dating?
Measures isotopes and rate of decay
Rate of decay?
Isotopes decay at a certain rate/ function of rate of decay-half life
Carbon 14
Can be used to measure back 50,000 years (carbon dating)
Isotope found in every living thing. Used when measuring age of living things
Uranium 238
Isotope used to measure back 4.5 billion years. Used to measure the age of earth.
Other ways we use to find out earth is old?
Fossil strata (layers of earth)
Earth is made up of layers:
Core- middle of earth (very hot, molten iron)
Mantle- middle layer (magma)
Crust- tiny (surface we live on)
Convection cycles
Like lava lamps, magma rises to crust, cools down, cycles back down. Takes 450 million years, gradual non stop process.
3 types of plate movement
Convergent
Divergent
Transform
Convergence
Running into each other
Fault type- reverse
Example- Himalayas
Divergent
Pulling away
Fault type- normal
Example- mid Atlantic ridge
Transform
Slide past
Fault type- strike slip
Example- San Andreas fault
Faults
Cracks were movement happens around plate boundary
Subduction zone
Two plates run into each other, more dense goes under the other.
Two continental crust
Neither sink, upward movement (mountains)
Mid Atlantic ridge
Maintain range bottom of ocean of divergent motion, runs from south hemisphere to north. (Iceland)
Extremophytes
Life living near volcano on bottom of ocean (super high pressure between boiling and freezing)
Transform boundary
North American plate and pacific plate
2 sources of water on earth
Outgassing (inside earth-natural)
Comets (ball of ice-ET)
