Plate Tectonics and Scientific Method Flashcards
What are the four major layers of the Earth’s interior?
Crust, Mantle, Outer core, Inner core
What is the upper 2 layer of the mantle called?
Lithosphere, astenosphere
What is the upper 2 layer of the mantle called?
Lithospher, astenospher
What is the depth of the continental curst?
0-65 km
What is the depth of the oceanic crust?
0-10 km
What is the depth of the mantle
45-2900 km
What is the depth of the outer core?
2900-5300 km
What is the depth of the inner core?
3500-6300 km
What is the density of the continental crust?
2.67 g/cm3
What is the density of the oceanic crust?
3.0 g/cm3
What is the density of the mantle?
4.5 g/cm3
What is the density of the outer core?
11.5 g/cm3
What is the density of the inner core?
13.0 g/cm3
What is the temperature of continental crust?
What is the temperature of the oceanic crust
What is the temperature of the mantle?
1100-5000 C
What is the temperature of the outer core?
5000-6000 C
What is the trend of the density
As closer to the center you get the denser it is due tot he heavier elements
What is the trend of the density
As closer to the center you get the denser it is due tot he heavier elements
What is the upper 2 layer of the mantle called?
Lithospher, astenospher
What is the depth of the continental curst?
0-65 km
What is the depth of the oceanic crust?
0-10 km
What is the depth of the mantle
45-2900 km
What is the depth of the outer core?
2900-5300 km
What is the depth of the inner core?
3500-6300 km
What is the density of the continental crust?
2.67 g/cm3
What is the density of the oceanic crust?
3.0 g/cm3
What is the inner core made of?
made of iron and nickel
What is the density of the outer core?
11.5 g/cm3
What is the density of the inner core?
13.0 g/cm3
What is the temperature of continental crust?
What is the temperature of the oceanic crust
What is the temperature of the mantle?
1100-5000 C
What is the temperature of the outer core?
5000-6000 C
What is the temperature of the inner core?
6000-6600 C
What is the trend of the density
As closer to the center you get the denser it is due tot he heavier elements
What is the crust made of?
CC- magnesium and aluminum rich silicates
OC-magnesium and iron rich silicates
What phase is the crust?
Solid
What phase is the mantle
semi liquid/solid (plastic)
What is the mantle made of
magnesium and iron rich silicates
What is the upper layer of the mantle and how deep is it?
250 km and Asthenosphere
What is isostasy?
the change in elevation of sections of the crust to balance pressure in upper mantle
What do subduction/convergent zones create
Trenches
Often form volcanic mountain ranges (magma comes up through cracks)
What phase is the inner core?
solid
What is the outer core made of?
made of iron and nickel
What is the inner core made of?
made of iron and nickel
What does the composition of the inner core contribute
the magnetic field
Describe the relationship between seismic waves and density
increase in seismic waves with increasing density
S-waves travel through
solids, not liquids
P waves travel through
liquids and solids
P waves are
penetrating waves
S waves are
shallow/ short waves
What determines S and P waves
the depth and strength
How is it hypothesized that the Earth is composed of iron and nickel
looked at planetary bodies (meteorites, asteroids, space rubble)
The inner layers are (pressure and temperature)
very hot and high pressure (so high, rock can deform and flow)
how many major plates are there
7 major and multiple smaller ones
How long do plates last
for a very long time but they do change
What did Alfred Wegener do
proposed that continents were moving
How are/were major geological features formed
they were boundaries of earlier plates
What are subduction/convergent zone
Where ONE plate is forced under another when 2 plates come together
What do subduction/convergent zones create
Trenches
Often form volcanic mountain ranges (magma comes up through cracks)
How does Plate tectonic theory relate to sea floor spreading
refinement of that hypothesis
- crust is 7 rigid plates
- new curst at mid ocean ridges
- curst sinks at convergence zones
What are transform faults?
Where plates slide horizontally past each other
Hot spots create
islands chains which indicate movement direction of crust
How does movement of plates happens
can happen over short periods, quick burst
can happen over long periods of time
What does short burst of movement create
high seismic activity–> Earthquakes
How does the mantle move?
In convection currents, hotter parts by outer core move up (heat rises) and cooler parts near crust sink creating a convection current
How fast do plates move in a year
average 1-17 cm per year
What does ridge steepness tell about speed of crusts
The steeper the ridge the slower the spreading (such as the mid-atlantic ridge compared to the East Pacific ridge)
What is Observing
The gathering of data with out altering the system being explained
What is an experiment
manipulation or control of system observed
What is a null hypothesis
No effect
What is an alternative hypothesis
does affect
What is a Hypothesis
an explanation for what is observed
What did Sir Francis Bacon notice
continents fit together like puzzle peices
What did Alfred Wegener do
proposed that continents were moving
What is support for the theory of plate tectonics?
Puzzle pieces
Topographic and continental features match
Biological similarities and fossils
What is the continental drift theory
plates moving but did not explain how
What is Sea Floor Spreading
plates moving by motion of sea floor (convection of mantle)
How does Plate tectonic theory relate to sea floor spreading
refinement of that hypothesis
-crust is 7 ridgid plates
Evidence used to test plate tectonics
- Mirror image patterns of magnetization
- Orientation of magnetic minerals in rock
- sediment thickness increases from ridge crest
- radiometrically dated
- magnetics and age indicate 200 million year old crust
- seismic activity and vulcanism
Hot spots create
islands chains which indicate movement direction of crust
What are hydrothermal vents
hot sea water is emitted near the ridge crest
- convection of seawater through hot volcanic rock
- hot salt water dissolves metals creating the plumes
What are ophiolites
section of ocean crust and lithified ocean sediment that have been uplifted onto land
