Pangea and Our Changing Atmosphere
Why does the formation and movement of land masses matter? These types of plate movements happen so slowly over such long time scales (relative to human existence) that it can seem like they are somewhat irrelevant to our modern lives. After all the Pacific plate, one of the fastest-moving plates globally, only moves about 3 to 4 inches each year!
There are two primary reasons that understanding plate movement and the associated land formation matters, however:
We will cover natural hazards in a later module, but here let's explore more in-depth the concept that plate movement produces atmospheric and climatic change.
First, Log in to BBLearn, go to Module 2, the Study Area, and Interactive Animations. Under Chapter 14, watch the animation "Assembly and Break-up of Pangea."
There are two primary reasons that understanding plate movement and the associated land formation matters, however:
- Plate tectonics is the driving force behind natural hazards such as volcanoes and earthquakes.
- Plate tectonics has produced considerable changes in Earth's atmosphere over the last 4.6 billion years.
We will cover natural hazards in a later module, but here let's explore more in-depth the concept that plate movement produces atmospheric and climatic change.
First, Log in to BBLearn, go to Module 2, the Study Area, and Interactive Animations. Under Chapter 14, watch the animation "Assembly and Break-up of Pangea."
Now, under Chapter 4, watch the Interactive Animation "Ocean Circulation Patterns."
Atmospheric and oceanic circulation patterns are key determinants of local, regional, and global climates. But these patterns themselves are determined by the location and size of land masses, and at times during Earth's past when continents were arranged in different patterns, ocean and atmospheric circulation patterns were also considerably different than today.
Go back to the Pangea animation again and try to guess how oceanic circulation might have looked 250 million years ago when the supercontinent formed. Pangea stretched from the North Pole to the South Pole across the entire range of Earth's latitude, and was a large landmass. This landmass would have successfully blocked the type of equatorial circulation and heat transfer away from the equator towards the poles that we see on Earth today.
Additionally, since the since was so large, there would have been considerable differences between the most inland regions and the edges of the continents near the oceans. This likely resulted in some impressive temperature and precipitation gradients!
While scientists are not 100% sure about what the climate of Pangea and the associated oceanic and atmospheric circulation looked like, they do know one thing for certain: the formation of Pangea coincided with the largest known mass extinction in Earth's history about 251 million years ago (the Permian-Triassic extinction). Unlike the extinction of the dinosaurs, which is widely believed to have been caused by a meteorite the size of Texas crashing into Earth, scientists hypothesize that the "Great Dying" is partially the product of the formation of Pangea. As the continents coalesced, circulation diminished and the global climate warmed, fundamentally altering ocean currents and causing the temperature of the oceans to rise and oxygen levels to lower. Every person who has ever had a fish tank at their house knows how important it is to keep the water oxygenated and cool, so imagine how badly the existing marine life fared when the exact opposite happened over a period of a few hundred thousand years.
Atmospheric and oceanic circulation patterns are key determinants of local, regional, and global climates. But these patterns themselves are determined by the location and size of land masses, and at times during Earth's past when continents were arranged in different patterns, ocean and atmospheric circulation patterns were also considerably different than today.
Go back to the Pangea animation again and try to guess how oceanic circulation might have looked 250 million years ago when the supercontinent formed. Pangea stretched from the North Pole to the South Pole across the entire range of Earth's latitude, and was a large landmass. This landmass would have successfully blocked the type of equatorial circulation and heat transfer away from the equator towards the poles that we see on Earth today.
Additionally, since the since was so large, there would have been considerable differences between the most inland regions and the edges of the continents near the oceans. This likely resulted in some impressive temperature and precipitation gradients!
While scientists are not 100% sure about what the climate of Pangea and the associated oceanic and atmospheric circulation looked like, they do know one thing for certain: the formation of Pangea coincided with the largest known mass extinction in Earth's history about 251 million years ago (the Permian-Triassic extinction). Unlike the extinction of the dinosaurs, which is widely believed to have been caused by a meteorite the size of Texas crashing into Earth, scientists hypothesize that the "Great Dying" is partially the product of the formation of Pangea. As the continents coalesced, circulation diminished and the global climate warmed, fundamentally altering ocean currents and causing the temperature of the oceans to rise and oxygen levels to lower. Every person who has ever had a fish tank at their house knows how important it is to keep the water oxygenated and cool, so imagine how badly the existing marine life fared when the exact opposite happened over a period of a few hundred thousand years.