html5-img
1 / 18

Igneous Rocks

Igneous Rocks. Igneous – “FIRE ROCKS”. From red-hot magma…. Extrusive Igneous Rocks. form when lava erupts from a volcano or “bubbles up” from tectonic plates moving apart - onto Earth’s surface. Ex: Basalt – the most common extrusive rock on Earth; forms most of Earth’s ocean floor.

kelvin
Télécharger la présentation

Igneous Rocks

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Igneous Rocks Igneous – “FIRE ROCKS” From red-hot magma…

  2. Extrusive Igneous Rocks form when lava erupts from a volcano or “bubbles up” from tectonic plates moving apart - onto Earth’s surface. Ex: Basalt – the most common extrusive rock on Earth; forms most of Earth’s ocean floor. Ex: Obsidian – black volcanic glass

  3. Igneous Rocks • Earth's Most Abundant Bedrock: Basalt Basalt forms more of Earth's surface than any other rock type. Most areas in ocean basins are basalt. May be on land from lava flows, too.

  4. Igneous Rock - Obsidian Obsidian was used to make knives, arrow heads, spear points, scrapers and many other weapons and tools

  5. How igneous rocks form… Extrusive When a volcano erupts or when magma bubbles to the surface Intrusive when magma cools slowly inside earth

  6. Intrusive Igneous Rocks • forms when magma hardens beneath Earth’s surface (INSIDE). Ex: Granite – the most abundantintrusive rock on Earth’s continents. Forms the core of many mountain ranges. Ex: Porphyry- looks like jello w/fruit inside it

  7. Intrusive Igneous Rocks • Granite is used to make many objects Granite is also well-known from its many world-famous natural exposures. These include: Stone Mountain, GA; Mount Rushmore, SD

  8. Intrusive Igneous Rock Porphyry—mixed texture (some large and some small grains)

  9. Igneous Rocks Texture – fine grained Rapidly cooling lava forms a fine-grained rock with small crystals. Ex: Basalt - crystals too small to be seen without a microscope. Ex: Obsidian –smooth, shiny texture like thick glass & cooled without forming crystals “Volcanic Glass”

  10. Igneous Rocks • Obsidian Obsidian on the side of a volcano

  11. Igneous Rocks Texture: coarse-grained Slowly cooling magma forms coarse-grained rock with large crystals • Ex: granite and porphyry

  12. Igneous Rocks – Mineral Composition Felsic: When magma is high in silica light-colored rocks form - like granite. Mafic: When lava is low in silica dark-colored rocks form - like basalt

  13. High Silica vs. Low Silica Felsic vs. Mafic

  14. Uses of Igneous Rock Granite – Statues, Bridges and old public buildings, Paving streets with cobblestone, floors, kitchen countertops (thin polished sheets of Granite)

  15. Uses of Igneous Rock Basalt - Gravel for construction Obsidian - Sharp tools for cutting and scraping (Native Am!), Starting vegetable gardens (fertilizer) – it’s called Perlite, which is formed from heating Obsidian

  16. Pumice is cool! It can float! • Pumice – used for cleaning and polishing

  17. Uses of Igneous Rock • Statues, Public Buildings - Granite

  18. Uses of Igneous Rocks • Cobblestone streets, kitchen countertops – Granite

More Related