Oreo Plate Tectonics

• Simulating plate boundaries with Oreo cookies. The upper cookie is the lithosphere, the creamy filling the asthenosphere, and the lower cookie the lower mantle. Carefully remove the upper cookie with a “twisting” motion.

• Divergent plate boundary, push down on the two broken cookie halves and slide them apart. Notice that the creamy filling between the two broken “plates” may tend to flow upward, similar to the rising and decompression of the hot asthenosphere at mid-ocean ridges and continental rift zones. (Ex: Iceland)

• Convergent plate boundary, push one cookie piece beneath the other. The very largest earthquakes are at subduction zones where two plates get stuck together for centuries, then suddenly let go. (Ex: Western Oregon)

• Transform plate boundary, slide the two cookie pieces laterally past one another, over the creamy filling. You can feel and hear that the “plates” do not slide smoothly past one another. (Ex: San Andreas Fault in California)