Plate Tectonics - Modern Evidence for Plate boundaries
It took another half-century, but Wegener's theory was finally proved true in the latter 20th century as Earth scientists accumulated evidence and observations addressing the two concenrs they had initially had about Wegener's theory. In developing a working theory of plate tectonics (or plate movement), scientists around the world accumulated four major pieces of evidence that initially were used to support a hypothesis about sea-floor spreading. What were these four pieces of evidence?
HINTS:
1. What does the following map show? How were the data acquired by scientists to create this map? How does it support the theory of plate tectonics?
HINTS:
1. What does the following map show? How were the data acquired by scientists to create this map? How does it support the theory of plate tectonics?
2. What does the following map show? How does this map support the theory of plate tectonics?
3. The map below shows the magnetic polarity Juan de Fuca plate just off the Washington coastline. How do reversals in polarity support plate tectonic theory?
4. The map below shows sediment thickness in the oceans (meaning the thickness of accumulated soil, sand, and rocks on top of the basalt ocean floor).
- Where are the thickest sediments found?
- Where are the thinnest sediments found?
- How does this map support the theory of plate tectonics?
- What other factors (besides the age of the underlying rock) do you think influence sediment thickness? (HINT: how did the sediments get there? Where did they originate?)
There are one other piece of evidence supporting plate tectonic theory that is not described in the book, but it played a key role in identifying what happens at plate margins, particularly spreading centers, and provided indisputable evidence that there were incredible geologic forces at work at the bottom of the ocean. This was the discovery of black smokers at spreading centers, and required advanced technology including vehicles that could dive all the way to the ocean floor and record video. Black smokers are vents at spreading centers (essentially mini-underwater volcanos).
Log in to BBLearn, click on Module 2, and go to the Study Area. In Videos, under Chapter 13, watch the short video called "Black Smokers."
When you have watched the video, go to Mastering Assignments in BBLearn and complete "Assignment 2.1: Plate Boundaries."
Log in to BBLearn, click on Module 2, and go to the Study Area. In Videos, under Chapter 13, watch the short video called "Black Smokers."
When you have watched the video, go to Mastering Assignments in BBLearn and complete "Assignment 2.1: Plate Boundaries."