DYNAMIC EARTH NOTES- DAY 3 (Honors and Academic)
Sea-floor spreading
Harry Hess in _____________________ came up with a Hypothesis: Sea-Floor Spreading


New ocean floor forms along Earth’s _________________________________________,
Slowly moves outward across ______________________________ causing the spreading.
As the seafloor spreads, our planet is not getting larger so we have to make up for this with
______________________________.
Subduction:



When the ocean floor returns to the ___________________________ via the deep trenches.
The oldest rocks are being pushed into the trenches and eventually are re-melted back into magma.
Rate of seafloor spreading is about ______________________________
Evidence for sea-floor spreading



Paleomagnetism
Earthquake Patterns
Age of ocean-floor rocks
DYNAMIC EARTH NOTES- DAY 3 (Honors and Academic)
Sea-floor spreading
Harry Hess in _____________________ came up with a Hypothesis: Sea-Floor Spreading


New ocean floor forms along Earth’s _________________________________________,
Slowly moves outward across ______________________________ causing the spreading.
As the seafloor spreads, our planet is not getting larger so we have to make up for this with
______________________________.
Subduction:



When the ocean floor returns to the ___________________________ via the deep trenches.
The oldest rocks are being pushed into the trenches and eventually are re-melted back into
magma.
Rate of seafloor spreading is about ______________________________
Evidence for sea-floor spreading



Paleomagnetism
Earthquake Patterns
Age of ocean-floor rocks
DYNAMIC EARTH NOTES- DAY 3 (Honors and Academic)
Paleomagnetism: The study of changes in Earth’s magnetic field shown by patterns of magnetism in rocks
that have formed over time.



___________________________: Rocks show the same magnetism as the present magnetism field.
___________________________: When rocks show the opposite magnetisms as the present
magnetism field.
The discovery of strips of alternating polarity, which lie as mirror images across the ocean ridges, is
among the strongest evidence of seafloor spreading.
Earthquake Patterns: Scientists found a relationship between deep-focus earthquakes and
________________________________________________________________________________
Age of the ocean floor:


In 1968, the ship Glomar Challenger collected data from both sides of mid-ocean ridges from deep
sea drilling.
They found that younger rocks were closest to the _____________________ and old rocks were
near the _______________________________________________________________________
Paleomagnetism: The study of changes in Earth’s magnetic field shown by patterns of magnetism in rocks
that have formed over time.



___________________________: Rocks show the same magnetism as the present magnetism field.
___________________________: When rocks show the opposite magnetisms as the present
magnetism field.
The discovery of strips of alternating polarity, which lie as mirror images across the ocean ridges, is
among the strongest evidence of seafloor spreading.
Earthquake Patterns: Scientists found a relationship between deep-focus earthquakes and
________________________________________________________________________________
Age of the ocean floor:


In 1968, the ship Glomar Challenger collected data from both sides of mid-ocean ridges from deep
sea drilling.
They found that younger rocks were closest to the _____________________ and old rocks were
near the _______________________________________________________________________