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.