What causes the movement of the tectonic plates?
(p.289) Tectonic plates move because of the pressure created at divergent plate boundaries, pushing the two plates away from one another. The plates also move because of convection currents in the asthenosphere, which pull the plates along with the magma current. 21. What model do scientists use to describe how rocks are created and changed? (p.247) Scientists use the rock cycle model to describe how rocks are created and changed back into sediment and into other kinds of rock. 22. Who first described the changes that rocks undergo? (p.249) In 1788, James Hutton first described the changes that are part of the rock cycle, and explained how geologic history can be explained by the arrangement of rock layers. 23. What are the three main kinds of rock? (p.247) Igneous, Sedimentary and Metamorphic. 24. Draw a flow map of the rock cycle. (p.247) The following is a flow map of the rock cycle: SHAPE \* MERGEFORMAT Magma Igneous Rock Metamorphic Rock Sediments Sedimentary Rock Compaction / Cem
