Vocabulary – Unit 8 – Plate Tectonics
1. magma – hot fluid or semi fluid material below or within the earth's crust
2. fossil - a remnant or trace of an organism from the past, such as a skeleton or leaf imprint,
embedded and preserved in the earth's crust
3. subduction – the sideways and downward movement of the edge of a plate of the earth's crust
into the mantle beneath another plate
4. Continental Drift Theory - a theory explaining the gradual movement of the continents across
the earth's surface through geological time
5. Alfred Wegener - a German scientist that proposed continental drift in 1912
6. mid-ocean ridge – underwater mountain ranges that can form at a divergent boundary
7. ocean trench - a long narrow trench when one plate goes under another at a convergent
boundary
8. rift valley – a gap at divergent boundaries where molten material rises to build new crust.
This can be at oceanic (mid-ocean ridges) and continental (volcanoes, lakes, rivers)
9. hot spot – heat from a plume (heated rising rocks in asthenosphere) melts some of the rock in
the tectonic plate above – can cause volcanoes to form
10. volcano – an opening in Earth’s crust through which molten rock, rock fragments, and hot
gasses erupt
11. plate boundaries – where the edges of two or more tectonic plates meet
12. convection – energy transfer by the movement of material – caused by differences in density
13. convection currents –continuous loop of sinking and rising of hot, soft rocks caused by
energy transfer in the asthenosphere (mantle) of Earth
14. fault - a crack in the earth's crust
15. Theory of Plate Tectonics – theory that stats that Earth’s lithosphere is made up of huge
plates that move over the surface of Earth