Alfred Wegener’s theory of continental drift was not widely accepted by the scientific community. Describe the weaknesses in his theory and discuss how the theory of plate tectonics offered a more complete explanation.
The main weakness was that Wegener could not explain how the continents
could plow through the seafloor, another problem he had was that he
couldn't find the mechanism that caused the continents to move across
the surface. So scientists rejected his hypothesis.
The theory of plate tectonics took evidence from the seafloor that
allowed the plates to move across the earth's surface. Scientists
noticed a long chain of volcanic mountains in the middle of the Atlantic
ocean and alternating parallel bands of rock with magnetic crystals of
differing polarity. Scientists were able to deduce that new oceanic
crust was being produced at the mid-ocean ridges (those volcanic
mountain ranges in the middle of oceans) and that magnetite crystals in
those rocks produced there were aligning themselves to the earth's
magnetic field at the time. And because of this they were able to deduce
that the new rock was pushing the older rock away from the mid-ocean
ridge, in turn moving the continents beyond the older seafloor
There is a mantle plume in the middle of the Pacific Ocean where magma
from deep within the earth's surface reaches the earth's surface. This
forms a volcano there. As the Pacific plate moves across the mantle
plume, new volcanoes form as old ones die because it is away from the
heat source. These volcanoes erode away, and as they do so the islands
formed by them slowly shrink until they are completely beneath the waves
Feb 9th, 2015
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