Prelim 1 Flashcards
When did Big Bang happen?
15 billion years ago
The elements in your body came from ____?
the center of stars
Inner planets are? Outer planets are?
rocky; gaseous
When was Earth formed?
4.6 billion years ago
What are the 5 oceans?
1) Pacific
2) Atlantic
3) Indian
4) Arctic
5) Southern
T/F There is an Antarctic Ocean
FALSE!! its the southern ocean
What is the average depth of the ocean?
4 km
Suppose you’re on a boat, 45 degrees north, 150 degrees west. What ocean are you in?
Pacific
Suppose you’re on a boat, 45 degrees north, 20 degrees west. What ocean are you in?
Atlantic
180 degrees west of the Prime Meridian in Greenwich England is where?
International Date Line in Japan
What is bathymetry?
topography of the bottom of the ocean
What are magnetic anomalies? How do they work?
proxy measure of geologic time; When new rock comes to surface (lava) magnetic minerals can orient to magnetic pole at that time; rock cools, minerals are locked in in one direction, others get locked in the opposite; positive and negative anomalies; seeing symmetry of those dates is really strong evidence that dead center has new rock, nailed this idea that axes are places of new rock formation
What are the driving mechanisms of plate tectonics?
convection in the mantle and slab pull
Define convection
Warm, buoyant magma like hot air balloon rises up and creates new oceanic material that moves ridges apart
Define Slab Pull
As you move away, you get older rock and colder and contracting, denser, to a point where you’re so dense that you’re heavier than the mantle, i.e. blankets hanging off bed and starts to pull whole rest of blanket behind it
Where does hot molten rock rise via convection?
divergent boundaries
Where does rock get pulled by gravity into the mantle?
subduction boundaries
Where do divergent boundaries occur? Only in mid-ocean ridges?
where plates are moving apart; most are mid-ocean ridges, less commonly continental rifts
Give an example where continental crust is colliding with oceanic crust
Andes Mountains, Cascade Mountains
Give an example where oceanic crust is colliding with oceanic crust
Japan
Where does sediment get its name?
from dominant material
What is a sediment accumulation rate?
1 cm/1000 years
How do you find proxy temperatures?
you can take isotopic ratios of Oxygen 18 and 16 in lab grown organisms to determine the proxy temperature of the ocean to find geologic past ocean temperature
What is wave dispersion?
B/c longer wavelength waves travel faster than short wavelength waves, the waves gradually sort out
If theres a storm off the coast of California, would you wanna go surfing? What if its way off the coastline?
no then yes b/c wave dispersion will have sorted out the waves
What is wave refraction?
wave comes in at an angle, one end of wave hits shallow water and slows down, deeper end stays fast, creates a bending of shallow-water wave fronts
What happens when a wave hits a headland?
underneath headland is ridge, center of wave crest is being slowed down b/c of shallower water, faster waters bend in on itself and focuses wave energy on point
What happens when a wave hits a bay?
bay has a low spot extending out perpendicular to beach that is shallower on either side, wave crest moves faster in middle, bends wave outward and defocuses energy, calm beach to swim in
Suppose u got up at 6, wanted to look during lowest tide. When could you wake up the next day? Why?
you could sleep in a little bit later; about 50 minutes later; b/c earth rotates on axis, moon is orbiting in same position, so earth has to move more to go back under the moon
Suppose you’re backpacking along washington state and you want to camp on the beach, want to get your tent close to the beach. Would full moon indicate being cautious?
YES! Exaggerated tide