Presentation on theme: "Warm-Up: Describe the texture and composition of each igneous rock."— Presentation transcript:
1Warm-Up: Describe the texture and composition of each igneous rock.
2Rocks Rock! Definition of A Rock A naturally occurring, solid, mixture of one or more minerals or organic matterClassified into 3 groups based on how they are formed: igneous, sedimentary, and metamorphicTexture and composition give clues as to how rocks are formed, and are used to classify and identify rocksRocks are always changing form in a cycle called the Rock Cycle
3Rock ClassificationComposition – the type of minerals a rock contains (ex: Limestone is 95% Calcite and 5% Aragonite)Texture – the size, shape and arrangement of the minerals that make up a rock. Can be fine, medium, or coarse.
4The Rock CycleThe main idea of the rock cycle is that rocks are continually changing from one type to another and back againThe elements that make up a rock are never created or destroyed - instead, they are constantly being recycled.
7Igneous Rock Form when magma cools and hardens. Sometimes look shiny and glasslike if lava cools quicklySometimes have tiny holes and spaces if gas is trapped in the rock as it coolsTwo examples are: Basalt and Obsidian
8Igneous Rocks Extrusive rocks- formed by cooling lava Texture Can Be:glassyporousfine-grainedIntrusive rocks- formed by cooling magmaTexture Is Always:coarse-grained
16Sedimentary Rock Formed from particles called sediments Fairly soft and break easilyContain sand, pebbles, stones, and is the only rock to contain fossilsExamples are: Conglomerate and LimestoneForm at or near Earth’ssurfaceMost have layers or strata
17Sedimentary Rocks Formed by: Weathering (breaking down of rock) Erosion (movement of sediments)Deposition (collection of sediments)Compaction & Cementation (sediments bonding together)
18Two Types of Weathering 1. Mechanical WeatheringRoot ActionFrost ActionMoss
19Types of Weathering 2. Chemical Weathering: Oxidation (rust) – Oxygen in air reacts with metals in rocksAcidic rain water
38Sedimentary rocks according to texture: Fine-grainedMedium-grainedShaleSandstoneCoarse-grainedConglomerate
39Metamorphic RockFormed under the surface of the Earth due to extreme heat and pressureHave ribbon-like layers and may have shiny crystals formed by minerals cooling slowly over timeTwo examples are: Gneiss and Marble
40Metamorphic RocksFormed by tremendous heat & pressure, and chemical reactions inside the crust.Formed from all three rock types.