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Author Question: Briefly explain how magnetic reversals in oceanic crust and fossils in ocean sediments are used to ... (Read 89 times)

jhjkgdfhk

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Briefly explain how magnetic reversals in oceanic crust and fossils in ocean sediments are used to
  construct a magnetic time scale. What will be an ideal response?



Question 2

How does seafloor spreading explain the movement of the continents? What will be an ideal response?



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yahahah24021

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Answer to Question 1

A terrestrial sequence of magnetic reversal in volcanic deposits was dated radiometrically. These dates
were extrapolated to regions which were not dated, but showed the same pattern of normal and
reversed magnetic polarities. Ages of ocean-floor basalts lying within a zone of normal or reversed
polarity are dated by the ages of the fossils found in the sediments that directly overlie the basaltic
crust. These fossils have already been incorporated within a biostratigraphic zone.



Answer to Question 2

With seafloor spreading, the continents and oceanic crust move together as part of large plates. The
plate is pushed by the formation of new ocean crust and pulled by the subduction of old ocean crust.
New crust forms due to seafloor spreading.






 

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