What type of rock are mid-ocean ridges made of?
basalt
What causes volcanoes to form along mid-ocean ridges?
In the ocean, volcanoes erupt along cracks that are opened in the ocean floor by the spreading of two plates called a mid-ocean ridge . Magma from Earth’s upper mantle rises up to fill these cracks. As the lava cools, it forms new crust on the edges of the cracks.
Are there earthquakes in the mid-ocean ridge?
Maps contrasting faulting on slow and fast spreading centers: (top) The Mid-Atlantic ridge has earthquakes both on the active transform and ridge segments. Strike-slip faulting on a near vertical plane parallel to the transform azimuth is characteristic.
Is there a relationship between the formation of volcanoes and the tectonic plates?
Most volcanoes form at the boundaries of Earth’s tectonic plates. At a divergent boundary, tectonic plates move apart from one another. They never really separate because magma continuously moves up from the mantle into this boundary, building new plate material on both sides of the plate boundary.
What are the three theories of plate tectonics?
Three-dimensional diagram showing crustal generation and destruction according to the theory of plate tectonics; included are the three kinds of plate boundaries—divergent, convergent (or collision), and strike-slip (or transform).
What are the two theories why tectonic plates move?
Why do plates move? One explanation for plate movements is slab pull. Plates are extremely heavy so gravity acts upon them, pulling them apart. Alternatively, as shown in the diagram, convection currents under the Earth’s crust transfer heat, which rises through the surface and cools back down in a circular motion.
Which statement best describes the main idea of continental drift?
Unit test
| Question | Answer |
|---|---|
| Which statement best describes the theory of continental drift in terms of evidence that the continents move and the mechanism driving their movement | The theory was supported by the evidence and included a mechanism |
Why was Wegener’s continental drift rejected?
The main reason that Wegener’s hypothesis was not accepted was because he suggested no mechanism for moving the continents. He thought the force of Earth’s spin was sufficient to cause continents to move, but geologists knew that rocks are too strong for this to be true.
What are the evidence that support continental drift theory?
In the early part of the 20th century, scientists began to put together evidence that the continents could move around on Earth’s surface. The evidence for continental drift included the fit of the continents; the distribution of ancient fossils, rocks, and mountain ranges; and the locations of ancient climatic zones.