Rock Cycle - Rocks (6A)
Pre Lab 

  • Discovering how rocks are formed through plate tectonics.
  • Comparing the formation of rocks.
  • igneous
  • metamorphic
  • plate tectonics
  • rock cycle
  • sedimentary
  • none

Students use a worksheet to determine the environments where rocks are formed.


Minerals make up rocks. Rocks formed in igneous, metamorphic, and sedimentary environments. The minerals found within each rock help to identify and name the rock, but the rock textures, such grain size, are also used in naming and identification.

Igneous rocks are formed when rocks are melted and then cool. Magma can cool slowly inside the crust and upper mantle of the Earth, forming rocks like granite. Granite has large minerals that can be seen with the naked eye. These are called plutonic rocks. Quick cooling magmas are generally erupted onto the Earth’s surface, called volcanic rocks. Igneous rocks are found where plates diverge, as lava rises and fills the gap between the plates. Igneous rocks also form where plates converge. The subducting plate melts as it sinks into the crust of the Earth, and the melt rises into the overriding plate forming volcanoes.

Metamorphic rocks are formed mainly in the lithosphere, wherever there is high pressure and high temperature. If the pressure and temperature are too high, metamorphic rock will melt and become magma. Metamorphic rocks are most abundant at convergent plate boundaries, but can occur in other areas where there are increased pressures and/or temperatures.

Sedimentary rocks form only on the surface of the Earth. Sedimentary rocks form in two main ways: (1) from clastic material (pieces of other rocks or fragments of skeletons) become cemented together, and (2) by chemical mechanisms including precipitation and evaporation. There are many environments associated with sedimentary rock formation, including oceans, lakes, deserts, rivers, beaches, and glaciers. They may form at all types of plate boundaries, but the thickest sedimentary rock accumulations occur at convergent plate boundaries. Fossils are associated with sedimentary rocks.


  1. Review rocks and rock forming environments. Use the illustration in the electronic presentation or draw the following diagram on the board and have the students predict where each type of rock formed.


  1. Remind the students that without the Plate Tectonic Cycle there would not be a rock cycle. Explain that the diagram only illustrates where the rocks formed, not where the rocks may be located now. As the plates move, they transport rocks away from where they formed.
  2. Have students complete the worksheet.

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