Which statement identifies a major reason for the subduction that helps to form volcanoes?(1 point)
Responses
the release of hot ash and steam in a pyroclastic flow
the release of hot ash and steam in a pyroclastic flow
the upwelling of magma between diverging plates
the upwelling of magma between diverging plates
the difference in density of oceanic and continental plates
the difference in density of oceanic and continental plates
the unusually high temperature at hotspots
the difference in density of oceanic and continental plates
Geologists observed signs of widespread ancient glaciers from the same time period in areas across South America, Africa, Antarctica, India, and Australia. What theory did this observation support?(1 point)
Responses
Earth was much farther than the sun than it is today.
Earth was much farther than the sun than it is today.
Glaciers were once more common than they are today.
Glaciers were once more common than they are today.
Those continents were once together as one supercontinent.
Those continents were once together as one supercontinent.
Most of Earth was once covered in a vast ice sheet.
Those continents were once together as one supercontinent.
To determine which statement identifies a major reason for subduction that helps to form volcanoes, we can evaluate each option and understand the process involved.
1. "The release of hot ash and steam in a pyroclastic flow": This statement describes the result of volcanic activity, specifically the explosive release of ash and steam. However, it does not explain the reason for subduction.
2. "The upwelling of magma between diverging plates": While this statement describes a process related to plate tectonics, it does not specifically address subduction, which refers to the sinking of one tectonic plate beneath another.
3. "The difference in density of oceanic and continental plates": This statement correctly identifies a major reason for subduction. Oceanic plates tend to be denser than continental plates, and when they collide, the denser oceanic plate sinks beneath the less dense continental plate, leading to subduction.
4. "The unusually high temperature at hotspots": This statement describes a different mechanism for the formation of volcanoes, known as hotspot volcanism. Hotspots are areas of exceptionally high temperature in the mantle, where magma can rise through the tectonic plates, creating volcanic activity. While this process can form volcanoes, it does not directly involve subduction.
Based on the explanations, the correct statement that identifies a major reason for subduction is "the difference in density of oceanic and continental plates."