Unit 2: Rocks Types and Their Formation Class Notes: Mrs. Cirillo

Rocks: General All rocks are classified on the basis of formation There are three categories: Igneous, Sedimentary, and Metamorphic Minerals make up rocks All rock info can be found in the ESRT p6,7

Igneous Rocks Are classified on basis of environment of formation and mineral composition Form by melting and solidification or crystallization of molten rock or magma/lava Make up Earth’s crust- oceanic-basalt Continental-granite

2 main categories: intrusive/extrusive Plutonic (underground) 2 main categories: intrusive/extrusive Cooling rate determines crystal size-short cooling time= long cooling time= see ESRT page 6 Volcanic (above ground) Small or fine grained Large or coarse grained

B A

How to use: Which minerals are found along this line (A) Is the rock mafic or felsic?_____________ Light or dark?________ High or low density?___ Copy the percents on an index card, and measure each one List the % of each mineral: Potassium feldspar, quartz, plagioclase feldspar, biotite, amphibole felsic light low

Potassium feldspar_________ Quartz___________ Biotite__________ Plagioclase feldspar___________ Amphibole_______________ 20% 40% 7% 15% 5% The percents should add up to 100%

Now repeat on other side as demonstrated... If the rock is non-vesicular, coarse grained, name the rock?______________ If the rock is vesicular, noncrystalline, name the rock?_______________ Now repeat on other side as demonstrated... granite pumice

List the % for each mineral: plagioclase feldspar_________ Line B List the % for each mineral: plagioclase feldspar_________ biotite____________ pyroxene__________ amphibole_________ olivine__________

Name the rock-fine grained, extrusive (using line B)_____________ A rock is plutonic, coarse grained, and non-vesicular containing 75% olivine_____________ A rock is volcanic, fine grained, and contains 15% potassium feldspar, 42% quartz, and 30% plagioclase feldspar___________ Basalt, vesicular basalt or diabase peridotite Vesicular rhyolite or rhyolite

http://www.classzone.com/books/earth_science/terc/content/investigations/es0603/es0603page01.cfm

Sedimentary Rocks Classified upon basis of formation Composed of WEATHERED remains of other rocks Form by compression and compaction of sediments (lithification) http://www.classzone.com/books/earth_science/terc/content/visualizations/es0604/es0604page01.cfm?chapter_no=06

Groups- Fragmental or clastic: Organic: Chemically(evaporites): Made from pieces of broken or weathered rock Fragmental or clastic: Organic: Chemically(evaporites): Made from the remains of plants Or animals Made from the Evaporation of sea Water, or as chemical Precipitates in Sea water http://www.classzone.com/books/earth_science/terc/content/visualizations/es0605/es0605page01.cfm?chapter_no=06

Will find fossils remains in these rocks!!!

See page 6 ESRT: Relationship of transported Particle Size to Water Velocity…. How is this table used in conjunction with the sedimentary rock table???

See page 7 ESRT: Scheme for Sedimentary Rock ID Classify Shale: Classify Limestone: Inorganic land derived sedimentary Rock consisting of clay particles Chemically or organically formed Crystalline or bioclastic rock consisting Of calcite

Name the rock: a clastic, fine grained (0.006cm) rock____________ Name the rock: a bioclastic, coarse grained rock that reacts with HCL___________________________ siltstone limestone

18. What type of relationship is shown on the graph? 16. How fast does a stream have to be traveling to transport a sediment 0.2cm, and what type of sediment is this? 17. How fast does a stream have to be traveling to transport a 27cm boulder? 18. What type of relationship is shown on the graph? 19. What process is this? 20. Can you infer how this may relate to producing various types of rock? 10cm/s 200cm/s Direct EROSION As the stream deposits sediments the different sedimentary rocks form

What is the map symbol for rock salt? Why do you think they choose that symbol? Because Halite has cubic shaped crystals

Metamorphic Rocks Igneous Form when sedimentary or igneous rocks undergo intense heat and/or pressure Have undergone significant changes deep within the earth Forms directly from another rock!!! Never melts (if melts what type of rock would it be?_________________) Igneous

Classified on the basis of formation Types of metamorphism: Regional: Contact: Form by heat and/or pressure During mountain building processes Or continental collisions Form by direct contact with molten rock (lava or magma)

Alignment or segregation of minerals In metamorphic rock, producing a Layered appearance Foliation: Banding: Distortion: Type of layering or foliation found in Some metamorphic rocks that is Caused by movement or growth Of minerals into homogenous layers Warping or bending of some Types of metamorphic rocks That occurs with intense pressure

Would you find fossils in this rock type? NO

Lets start with shale…. Shale slate Rhyolite schist Granite gneiss

Let’s look at the diagram below: Relate the depth to heat and pressure and the ESRT

Using page 7, Scheme for Metamorphic Rock ID answer… Non foliated fine to coarse Regionally formed Metamorphism of sandstone Classify Quartzite: 2. Classify Marble: 3. Which rock is the result of intense metamorphism? 4. Give an example of a fine grained foliated rock? Metamorphism of limestone Non foliated, contains calcite GNEISS slate