Which statement correctly summarizes Wegener’s theory of continental drift?
A. All seven continents have always been in the same locations on Earth as they are today.
B. When a meteorite crashed onto the planet, it broke the giant supercontinent Pangaea into smaller landmasses.
C. The seven continents on Earth drifted until they formed one giant supercontinent, which Wegener called Pangaea.
D. Over tens of millions of years, the giant supercontinent Pangaea began to slowly drift apart, forming the continents as they are known today.
The Correct Answer and Explanation is:
The correct answer is D. Over tens of millions of years, the giant supercontinent Pangaea began to slowly drift apart, forming the continents as they are known today.
Explanation:
Wegener’s theory of continental drift proposed that the continents were once part of a single supercontinent known as Pangaea. According to this theory, Pangaea existed during the late Paleozoic and early Mesozoic eras, around 300 million years ago. Over time, Pangaea began to break apart due to the movement of tectonic plates, and the pieces of this supercontinent drifted to their current positions over millions of years. This slow drifting process is what led to the formation of the separate continents as they are today.
Wegener’s theory was based on several key pieces of evidence:
- Fossil Evidence: Similar fossils of plants and animals were found on continents that are now widely separated by oceans, suggesting that these landmasses were once connected.
- Geological Evidence: Similar rock formations and mountain ranges were found on continents that are now distant, implying that these landmasses were once part of the same landmass.
- Paleoclimatic Evidence: Evidence of past climates, such as glacial deposits and coal beds, indicated that continents like South America and Antarctica were once located closer to the South Pole, supporting the idea of continental movement.
While Wegener’s idea was revolutionary, it was initially met with skepticism because he could not explain the mechanism behind the drifting continents. Later, the theory of plate tectonics, which describes the movement of Earth’s lithosphere on the more fluid asthenosphere beneath, provided the necessary mechanism to explain continental drift.
Thus, Wegener’s theory set the stage for our modern understanding of Earth’s dynamic surface, which continues to evolve due to the movement of tectonic plates.