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Questions | Answers

1. Theory of Plate Tectonics

2. Convection cells in the mantle bring magma to surface, which then spreads out, cools, becomes more sense, and sinks into the mantle creating slab pull and slab suction.Convection cells in the mantle.

3. Plate Boundaries

  • Divergent Plate Boundary: rifts, ridges, new oceanic crust.
  • Ocean-Continent Convergent Plate Boundary: volcanic mountain chains, trenches.
  • Ocean-Ocean Convergent Plate Boundary: volcanic island arcs, trenches.
  • Continent-Continent Convergent Plate Boundary: upfolded mountains.
  • Transform Plate Boundary: strike-slip faults

4. Hotspots are where a plume of magma comes up and breaks the surface, spewing out lava. The Hawaiian Island chain formed as the Pacific Plate moved over the top of the stationary hot spot, forming a chain of volcanoes.

5. Explosive volcanoes occur as a result of subduction when the light weight material melts in the mantle and comes back up explosively (occur at Ocean-Continent Convergent Plate Boundaries and Ocean-Ocean Convergent Plate Boundaries).
Blooping volcanoes occur when the regular, heavier mantle material is forced to the top by convection or in a mantle plume (occur at Divergent Plate Boundaries and Hotspots).

6. Oceans form when the regular mantle material is forced to the surface. This material is dark, heavy, and dense and sinks farther into the mantle so forms the low regions on Earth that fill with water, making the ocean basins.
Continents form from the light in color and light in weight materials of the Earth that float high in the mantle, thus stick up above the ocean basins.

7. Along plate boundaries and at hotspots.