Vocabulary #12 (Moving Plates)

Definitions:

1. crust: Earth's solid, rocky surface containing the continents and ocean floor
2. original horizontally: the idea that many kinds of rock form in flat, horizontal layers
3. continental drift: the idea that a supercontinent split apart into pieces, the continents, wich drifted in time into their actual location
4. sea-floor spreading: the idea that new crust is forming at ridges in the sea floor, spreading apart the crust on either sides of the ridges
5. magma: hot, molten rock below Earth's surface
6. plate tectonics: the idea that Earth's surface is broken into plates that move
7. mantle: Earth's layer beneath the crust
8. subduction: where plates collide, the sliding of a denser ocean plate under another plate

Sentences and illustration:

1. During a suden motion of the crust an eathquake or volcanic eruption occurs.

2. The twist or tilted of the rock are signs of original horizontally.

3. Alfred Wegener reasoned the continental drift idea.

4. The sea-floor spreading model was suggested in early 1960's.

5. Magma flows up through the cracks, cools, and hardens into new solid material along the ridges.

6. In late 1960's scientists develop the tectonic plates model.

7. Paltes move around on the lower potion of the mantle.

8. Subduction is part of a cycle.