1 / 9

Igneous Rocks

Igneous Rocks. Pg. 19. Igneous rocks. Formed from the crystallization of magma Comes from L atin word ‘ ignis ’ meaning fire Lava- magma that flows onto Earth’s surface. Types of Igneous Rocks. Extrusive- fine-grained rocks that cool quickly on Earth’s surface

yair
Download Presentation

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 Pg. 19

  2. Igneous rocks • Formed from the crystallization of magma • Comes from Latin word ‘ignis’ meaning fire • Lava- magma that flows onto Earth’s surface

  3. Types of Igneous Rocks • Extrusive- fine-grained rocks that cool quickly on Earth’s surface • Intrusive- course-grained rocks that cool slowly beneath Earth’s surface (ex. Granite)

  4. Composition of Magma • Mix of molten rock, gas, and mineral crystals • Silica (SiO2) is the most abundant component of magma and has the greatest effect on its characteristics • 3 types of magma: • Rhyolitic • Andesitic • Basaltic

  5. Melting Rocks • Partial melting- the process in which some parts of a rock melt while others don’t due to the mineral compositions • Fractional crystallization- the process where different minerals form at different temperatures

  6. Classifying Igneous Rocks • There are 3 main groups of igneous rocks • Felsic: light-colored, high silica content, contain quartz • Mafic: dark- colored, low silica content, rich in iron and magnesium • Ultramafic: very low silica content and very high iron and magnesium content • Can have intermediate rocks

  7. Grain Size • Quick cooling lava leads to smaller grain size • Slower cooling lava leads to larger grain size

  8. Texture • Geologists cut thin slices of the rocks and study them under microscopes to determine texture • Porphyritic texture- characterized by large well formed crystals surrounded by finer-grained crystals

  9. Resources • Useful as building materials because of interlocking grain textures • Ex. Granite • Ores can be found in igneous rocks • Sometimes valuable elements are found in the veins of igneous rocls • Veins of large grained minerals- pegmatites • Diamonds are formed from kimberlites

More Related