 Boulder Boogie  A mystery in Death Valley:  What moved this rock across the desert floor?  Scientists call it the “dancing rocks”.  Visitors call the dry lake bed, the “Racetrack”.

 Boulder Boogie  A mystery in Death Valley:  What moved this rock across the desert floor?  Several times a year, powerful storms rip across the lake bed, bringing plenty of rain, wind & snow. The clay surface becomes slippery, and that’s when the rocks dance.

 Objectives 1. Describe two ways a rock can undergo metamorphism. 2. Explain how the mineral composition or rock changes as the rocks undergo metamorphism. 3. Explain how metamorphic rock structures are related to deformation.

 Contact Metamorphism- Heated by nearby magma.  Regional Metamorphism- When pressure builds up in rock that is buried deep below other rock formations or when large pieces of the Earth’s crust collide with each other.

Rocks were once sedimentary, igneous, or another metamorphic rock. These rocks are physically deformed & chemically changed due to different temperatures and pressures.

The original minerals in a rock change into new minerals that are more stable in new pressure & temperature conditions.

 Metamorphic rock structures are caused by deformation.  Deformation is a change in the shape of a rock caused by a force placed on it.  Ex. Sedimentary shale becomes foliated metamorphic rock slate.

 Foliated- The texture of metamorphic rock in which the mineral grains are arranged in planes or bands. Ex. Gneiss  Non-foliated- the texture of metamorphic rock in which the mineral grains are not arranged in planes or bands. Ex. Marble

 Objectives 1. Describe two ways a rock can undergo metamorphism. 2.Explain how the mineral composition or rock changes as the rocks undergo metamorphism. 3.Explain how metamorphic rock structures are related to deformation.