DIscussion 4-1
docx
keyboard_arrow_up
School
Southern New Hampshire University *
*We aren’t endorsed by this school
Course
PHY103
Subject
Geology
Date
Jan 9, 2024
Type
docx
Pages
3
Uploaded by CountWorld12585
As it stands Alfred Wegner’s hypothesis of continental drift is
invalid. However, Wegner does argue some compelling and
thought-provoking points that deserve further investigation.
He has presented the idea that the continents were all
connected and fit together at one point in time in the distant
past. The name given to this super continent is Pangaea. He
theorizes that it was in the southern hemisphere near
Antarctica. Due to its latitude much of the land was covered in
an ice sheet that there is evidence of in present day South
America, Africa, India, and Australia. If these continents have
remained in place, there is no explanation for how glacial ice
could have formed in sheets so near to the equator. Wegner
has also done research that has found rocks and geologic
features across continents form a continuous picture. One of
the pieces of evidence that is presented is the mountain chain
that spans from North to South on the eastern side of the
United States and into Canada can be matched with
mountains also found in the British Isles and Scandinavia,
when placed together in the manner that Wegner has
proposed they match up to form a continuous belt. Another
suggestion brought up to support the idea of continental drift
is the matching fossils found across oceans. The fossils of an
ancient creature called Mesosaurus has been found in South
America as well as in Africa. Glossopteris has been found on
several continents: Australia, Antarctica, India, Africa, and
South America. How this came to be, has yet to be explained,
however other scientists have suggested that it is possible
that rafting, transoceanic land bridges, and island stepping
stones could have allowed for the transfer of the creatures
and plants. Wegner has suggested that the forces that
permitted for the continents to drift could be gravitational
forces, however Harold Jefferys has pointed out that if this was
the case then the rotation of our entire planet would have
stopped. Wegner has also presented the idea that it is possible
that the continents broke through the thin oceanic crust, but if
this was to be the case in this process the continents would be
thoroughly deformed, which does not fit with the theory that
the continents fit together like puzzle pieces. Until there is a
mechanism by which the continents can be moved, there is no
validity to the continental drift theory.
The similar theory of plate tectonics is very much a valid
theory and has the research and evidence necessary to
support it. If Alfred Wegner had the technology available to
him, I think his continental drift theory would have looked
extremely similar to the plate tectonics theory. After World
War II there was research conducted on the oceanic floors the
revitalized scientist’s interest in continental drift. This research
revealed a very long system of mid-ocean ridges. When the
oceanic crust was sampled, it revealed that it was much
younger than the continents surrounding it. The evidence that
validates the plate tectonics theory is discovery of how the
lithosphere and aesthenosphere relate to one another. The
lithosphere is the Earths outermost layer, Consisting of crust
and the upper part of the mantle. It is also known for being
rigid and when it deforms it bends or breaks. Underneath this
layer is the aesthenosphere. This part of the Earth is weaker
than the outer crust, yet is still solid rock, but instead of
breaking or bending under pressure, it flows. This allows the
two layer to act separately of each other. The lithospheric
plates themselves are many different sizes. Along the
boundaries of where they meet is the most major interactions
occur, leading to crustal deformation and other major geologic
events, such as earthquakes and volcanoes. The type of
boundary between the plates most often determines what
events will be seen. In a divergent boundary the plates are
moving away from each other, leading to upwelling and
creation of new seafloor. A convergent boundary is made up of
two plates colliding with each other, the oceanic or denser
plate will be subducted beneath the other. This often leads to
the creation of volcanoes and mountain ranges. The last
boundary is a transform boundary, where two plates are
sliding laterally past each other. Unlike with continental drift,
the evidence for plate tectonics is clearly supported by a
mechanism that is scientifically proven.
Source :
Lutgens, F. K., & Tarbuck, E. J. (2021).
Foundations of Earth Science
(Ninth Edition). Pearson
Education Inc.
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help