1. Metamorphic Rocks

2. A. Vocabulary 1. Parent rock: Preexisting rock 2. Recrystallization: A process in which rocks undergo change without truly melting

3. B. Key Ideas: HEAT AND/OR PRESSURE 1. Formed when existing rocks (igneous, sedimentary or metamorphic) are changed by HEAT AND/OR PRESSURE 2. The new rocks may resemble the “parent” rock in their mineral composition/color CANNOT MELT 3. IMPORTANT- THE ORIGINAL ROCK CANNOT MELT WHEN IT BECOMES METAMORPHIC! (If it melts and solidifies, it’s igneous !)

4. Activity- Listen closely to directions! 1. Send one group member to the front to pick up the playdough 2. Carefully stack playdough slabs on top of each other without blending them in any way. A. Of the rock types we have talked about already, which type forms like this? 3. Now, fold the playdough layers in half and push down 4. What are some observations?

5. Animation of Metamorphism Metamorphism

6. C. The 2 Types of Metamorphism 1. REGIONAL: 1. REGIONAL: Large areas of rock are changed by HEAT & PRESSURE

7. Metamorphic mountains formed from regional metamorphism

8. 2. CONTACT: 2. CONTACT: Magma touches layers of rock and the HEAT causes the rock layers to change a. Little to no pressure is involved with contact metamorphism (Contact Touch) “Liquid hot magma!”

9. Alaska’s Copper Mountain – contact metamorphism

10. D. the bells & whistles for metamorphic rock identification 1. BANDING different colored minerals due to sorting by density 1. BANDING – alternating layers of different colored minerals due to sorting by density a. These bands are usually distorted from the heat & pressure b. not to be confused with sedimentary layers (stratification)!!!

11. Stratification vs. Banding

12. Stratification (sed) vs. Banding (metamorphic)

13. FOLIATION 2. FOLIATIONmineral alignment 2. FOLIATION – mineral alignment – the minerals in the rock are layered, which causes breakages to often occur along flat surfaces- look for “scratches” in the rocks

14. Foliation – note the “scratches” in the rock – this is mineral alignment! More foliation – slate & phyllite Banding – mica schist Excellent example of banding & distortion – this is GNEISS Excellent example of banding & distortion – this is GNEISS

15. More GNEISS More GNEISS GNEISS

16. E. Difference Between Marble and Quartzite a. Both are white in color b. Marble reacts with HCl (hydrochloric acid) and quartzite does not because marble is composed of recrystallized Calcite

19. Remember… MORPHING is all about CHANGE! Animoto Video

21. When I was young, liquid granite I was diagnosed schizophrenic Neither feldspar, nor mica, nor quartz But the sum of the three Bonded igneously That means melted together for life Well, I was hot and dejected Oh, I was injected Under layers and layers of dirt But, it was there that I changed All my crystals rearranged Into G-N-E-I-S-S, gneiss So, take a look, and you'll see That I'm not what I used to be I've been touched metamorphically All the heat and the pressure Have changed me forever So don't take me for granite, I'm gneiss Well, I wasn't to been seen Until time changed the scene Exposing my face to the sun But, now its here that I sit Being worn down bit by bit Oh, erosion is wearing me down Refrain So, be aware, have a look Underground or underfoot For that beautiful pinky-gray face The Canadian shield Holds a magnamous yield Of the rock that was changed into gneiss Refrain The GNEISS SONG

22. Okay… Let’s sum up!

23. There are 3 classifications of ROCKS IgneousIgneous – formed by the cooling of magma (melted rock) SedimentarySedimentary – formed by compaction & cementation of rock fragments MetamorphicMetamorphic – formed by heat & pressure changing existing rocks

24. Remember the “bells & whistles” when identifying rocks! Igneous – obvious crystals of different mineralsIgneous – obvious crystals of different minerals Sedimentary – stratification, fragments, fossilsSedimentary – stratification, fragments, fossils Metamorphic – foliation, bandingMetamorphic – foliation, banding