Aim: How do metamorphic rock form? Do Now: 1) How many rock types are there? 2) What are the names of the different rock types?,,. 4) When we talk about intrusive and extrusive, we are talking about rocks. 5) When we are talking about clastic (inorganic), chemical, and organic, we are talking about rocks. 6) What rock is formed from seashells? 7) What rock is formed from plants in a swamp? 8) What rock is formed from sea water that has evaporated?
Homework: Rocks of the Reference table worksheet Vocab: Foliation Banding Contact Metamorphism Regional Metamorphism
Aim: What are Metamorphic Rocks? Metamorphic rocks: A rock that RECRYSTALLIZES due to HEAT and/or PRESSURE WITHOUT MELTING (solid state).
(Sedimentary) Shale Slate Phyllite Schist Gneiss
Aim: What are Metamorphic Rocks? Metamorphic rocks can be: Marble crystalline in appearance (with interlocking grains) foliated - apparent layering (but they're not really layered) Schist Gneiss
Foliation http://www.classzone.com/books/earth_science/terc/content/visualizations/es0607/es0607page 01.cfm?chapter_no=visualization
Aim: What are Metamorphic Rocks? Foliated rocks can have mineral alignment or banding. Mineral Alignment: Banding: Gneiss
Aim: What conditions form metamorphic rock? Types of Metamorphism 1. Regional Metamorphism 2. Contact Metamorphism
Aim: What conditions form metamorphic rock? Types of Metamorphic rocks Regional Metamorphism: A whole area is put under pressure. With depth there is an increase in temperature and pressure. This can happen at a convergent plate boundary Slate Phyllite Schist Gneiss http://www.ig.uit.no/~kaarek/geology_intro/metamorphism.swf Go to Regional Metamorphism Do Now Page
Aim: What conditions form metamorphic rock? Contact Metamorphism: Rocks that are in close contact with magma will metamorphose into a new rock. http://www.ig.uit.no/~kaarek/geology_intro/metamorphism.swf Go to Contact Metamorphism Contact Metamorphism happening the the Pallisades in NJ
Degree of Metamorphism: Amount of change that occurs. HIGH degree (grade) : MORE CHANGE or RECRYSTALLIZATION High T and P LOW degree (grade) : LESS CHANGE or RECRYSTALLIZATION Low T and P
Changes that occur on a rock during metamorphism: a) Hardness b) Coarseness (texture) c) Density AS HEAT and/or PRESSURE INCREASE, THE CHANGES INCREASE Softer Finer Less Dense More Metamorphosed and Recrystallized Heat and/or Pressure INCREASES HARDER COARSER DENSER
METAMORPHIC FEATURES: I) Distorted Layering II) Foliation (mineral alignment): Layering with 2 or more minerals Slate or Schist (slaty) III) Banding: Layers made by mineral density Layers are dark (dense) and light (less dense) in color. DARK, DENSE LIGHT, LESS DENSE DARK, DENSE (schistosity) Gneiss (gneissic) LIGHT, LESS DENSE IV) Non Foliation No Layering, Only one mineral
DISTORTED LAYERS FOLIATION SLATE SCHIST WITH FOLIATION FOLIATION SCHIST PHYLLITE
GNEISS BANDING DISTORTED LAYERS
NON FOLIATION QUARTZITE MARBLE
7. High Degree (grade) Low Degree (grade) More Recrystallized Harder Coarser Denser Less Recrystallized Softer Finer Less Dense
METAMORPHIC ACTIVITY 1. Draw a graph that best describes the relationship between the following variables and when heat and pressure increase during metamorphism. Hardness Heat and Pressure Coarseness Heat and Pressure Density Heat and Pressure Degree of Metamorphism Heat and Pressure Recrystallization Heat and Pressure 2. Based on the five graphs above, describe what happens to a rock during metamorphism as the heat and pressure increase. 3. A metamorphic rock has a different appearance when the degree of metamorphism and recrystallization increases are decreases. Below is a list of terms representing the different characteristics a rock can possess during metamorphism. Read each term and decide if that characteristic represents a metamorphic rock has been HIGHLY (more) or LESS metamorphosed and place it in the appropriate column. Less Dense, Coarse, Very Dense, Less Recrystallized, Soft, Finer, Harder, Highly recrystallized High Metamorphosed Less Metamorphosed Less Dense