How does the presence of mid-ocean ridges give evidence of continental drift? (1 point)
Responses
Mountains show that tectonic plates move toward each other.
Mountains show that tectonic plates move toward each other.
Magma from the mantle moves in a circular motion depending on temperature.
Magma from the mantle moves in a circular motion depending on temperature.
Magma erupts from volcanoes showing that the mantle is below the crust.
Magma erupts from volcanoes showing that the mantle is below the crust.
Seafloor spreading shows that tectonic plates move away from each other.
Seafloor spreading shows that tectonic plates move away from each other.
Seafloor spreading, which is closely tied to mid-ocean ridges, provides evidence for continental drift. Here's how it works:
1. Mid-ocean ridges are underwater mountain ranges that run through the center of many ocean basins. These ridges are constantly being created as new oceanic crust is formed at divergent plate boundaries, where tectonic plates move away from each other.
2. Along the mid-ocean ridges, magma from the mantle rises up and fills the gap left by the separating plates. This molten rock cools, solidifies, and forms new oceanic crust, pushing the existing crust away from the ridge. This process is called seafloor spreading.
3. As new oceanic crust forms and spreads away from the ridge, it gradually moves away from the mid-ocean ridge in both directions. This movement can be measured using various techniques, such as paleomagnetism and GPS. These measurements provide evidence of the pattern and rate of seafloor spreading.
4. The spreading of the oceanic crust on either side of the mid-ocean ridge creates a symmetrical pattern of older, more distant crust further away from the ridge, and younger, closer crust near the ridge. This pattern is observed through magnetic anomalies, where the magnetic field of the Earth's crust preserves the polarity of the time it was formed.
5. By comparing the ages of the oceanic crust on either side of the mid-ocean ridge, scientists found that the crust gets progressively older as they move away from the ridge. This observation supports the idea that new crust is continuously forming at the ridge and moving away from it, which is a key component of the theory of plate tectonics.
So, the presence of mid-ocean ridges and the process of seafloor spreading provide evidence that tectonic plates are moving away from each other, supporting the concept of continental drift.