Rocks, Rocks and More Rocks! Igneous Sedimentary Metamorphic
Igneous Rocks • Notes: Extrusive Igneous Rocks Rock formed from lava that erupted onto Earth’s surface. Basalt – most common extrusive rock on Earth. It forms most of Earth’s ocean floor.
Igneous Rocks • Earth's Most Abundant Bedrock Basalt underlies more of Earth's surface than any other rock type. Most areas within Earth's ocean basins are underlain by basalt. Although basalt is much less common on continents, lava flows and flood basalts underlie several percent of Earth's land surface. Basalt is a very important rock.
Igneous Rocks • Notes: • Intrusive Igneous Rocks Rock formed from magma that has hardened beneath Earth’s surface. Granite – the most abundant intrusive rock on Earth’s continents. Forms the core of many mountain ranges.
How igneous rocks form Extrusive Intrusive
Granite is also well-known by its many world-famous natural exposures. These include: Stone Mountain, Georgia
Igneous Rocks Granite is the best-known igneous rock. Many people recognize granite because it is the most common igneous rock found at Earth's surface and because granite is used to make many objects that we encounter in daily life. These include counter tops, floor tiles, paving stone, curbing, stair treads, building veneer and cemetery monuments. Granite is used all around us - especially if you live in a city. Facts about granite:
Igneous Rocks • Granite
Igneous Rocks • Notes for Texture: • Fine grained Rapidly cooling lava forms a fine-grained rock with small crystals. Example: Basalt - glassy texture, crystals too small to be seen without a microscope. Example: Obsidian –smooth, shiny texture like thick glass & cooled without forming crystals.
Igneous Rocks • Obsidian Obsidian on the side of a volcano
Igneous Rocks • Notes for Texture: • Coarse-grained Slowly cooling magma forms coarse-grained with large crystals Example: Granite and Porphyry which looks like gelatin with chopped fruit
Mineral Composition • Notes: When rocks are high in silica they form light-colored rocks like Granite.
Uses of Igneous Rock • Notes: All made from Granite • Statues • Bridges • Buildings • Paving streets • Curbstones • Floors • Countertops
Uses of Igneous Rock • Gravel for construction – Basalt • Cleaning and polishing – Pumice • Sharp tools for cutting – Obsidian • Fertilizer – Perlite, which is formed from heating Obsidian
Uses of Igneous Rock • Statues, Public Buildings - Granite
Uses of Igneous Rocks • Cobblestone streets, kitchen countertops