Rocks Poweroint
- 1. Rocks, Rocks, and more Rocks!!!! http://en.wikipedia.org/wiki/Stone_hedge
- 2. What is a rock? A solid mixture of crystals of one or more minerals.
- 3. What’s so great about rocks? Used to make tools & weapons Spears & arrow heads Obsidian scalpels used in delicate operations Used to make buildings (new & old) Some contain fossils which help scientists learn about the past.
- 4. The Rock Cycle (pg. 82) The process by which one rock type changes into another. The rock cycle takes millions of years.
- 5. 3 processes that change one rock type to another. Weathering & Erosion Heat & Pressure Melting & Cooling
- 6. 3 Types of Rocks Igneous Rock Sedimentary Rock Metamorphic Rock Rocks are classified based on how they were formed (weathering and erosion, heat and pressure, melting and cooling).
- 7. Subtypes Igneous, Sedimentary, & Metamorphic are divided into subtypes based on differences in how rocks are formed. Two criteria: 1. Composition 2. Texture
- 8. 1. Composition Composition is the minerals of which a rock is made of. Examples: (pg. 85) Limestone – 95% Calcite, 5% Aragonite Granite – 10% Mica, 35% Quartz, 55% Feldspar
- 9. 2. Texture Texture is the sizes, shapes, and positions of the grains of which a rock is made. a. Fine-grained – made of small grains Ex. Silt or clay particles b. Coarse-grained – made of large grains Ex. Pebbles c. Medium-grained – fine and medium texture Ex. Sand
- 10. Igneous Rock Igneous is Latin for “fire” Igneous rock forms from cooling lava and magma.
- 11. Igneous - Composition Felsic vs. Mafic Lighter in color Less dense Made up of elements such as: Silicon Aluminum Sodium Potassium Ex. Granite Darker color More dense Made up of elements such as: Iron Magnesium Calcium Ex. Basalt
- 12. Igneous – Texture Intrusive vs. Extrusive Magma cools beneath Earth’s surface. Cools very slowly Coarse-grained texture Large crystals Ex. Granite Lava cools on the Earth’s surface. Cools very quickly Fine-grained texture Small or no crystals Ex. Basalt
- 13. Sedimentary Rock Sediment = rock fragments caused by erosion Sediments are compacted and cemented together to form sedimentary rock. Strata – the layers seen in sedimentary rock
- 14. Sedimentary – Composition Clastic , Chemical , Organic Clastic – fragments of other rocks and minerals Size and shape of rock fragments influence the names of sedimentary rocks Look at pg. 92, Figure 17 for example. Ex. Conglomerate Chemical – forms from solutions of minerals and water Rainwater dissolves small pieces of rock and washes into the ocean where it eventually forms new minerals (Fig. 18) Ex. Limestone
- 15. Sedimentary – Composition Clastic , Chemical , Organic Organic – rock which forms from the remains of animals Ex. Bituminous coal (made of plant matter) What about fossils? They can be found in ALL types of sedimentary rock.
- 16. Sedimentary – Texture Stratification Stratification – layering, the layers differ depending on the kind, size, and color of the sediment. - Check out Fig. 21 & 22 on pg. 94 for examples.
- 17. Metamorphic Rock Meta means “changed” Morphos means “shape” The structure, texture, or composition of the rock has changed by pressure, heat, or the combination of both.
- 18. Origins of Metamorphic Rocks Contact Metamorphism – when rocks come into contact with magma, heat “cooks” the rock Change due to temperature Regional Metamorphism – when a lot of pressure causes large pieces of Earth’s crust to collide with one another Change due to pressure
- 19. Metamorphic - Composition Heat and pressure cause minerals in the original rock to change into other minerals.
- 20. Metamorphic – Texture Foliated vs. Nonfoliated Minerals are aligned by pressure Looks like pages in a book Ex. Slate,Phyllite No regular pattern One or only a few minerals Ex. Marble, Quartzite