Name Chapter 6 Rocks NOTES 6.2 Igneous Rocks Pgs. 121 - 126 1. Igneous Rock Formation Form from the __________________ of molten rock - _______________________ (volcanic)- form at or near the surface from lava - Intrusive (_______________) – form under the surface from magma Igneous rocks are classified by ____________________ composition (mafic or felsic) and __________________ Texture - ____________, shape and arrangement of grains (______________) - Grain or crystal ___________ depends on: o ________________ of cooling Fast = ______________ ________________ = large o ___________________ _____________ More = _______________ o Order of solidification 2. The Starting Material Magma is classified as Felsic, Mafic or Intermediate Felsic - _______________ colored - ___________ silica magma with abundance of quartz and feldspar. - _______________ slow flowing in molten state. - Most __________________ rocks. - Acidic Mafic - ________________ colored, - Low silica ferromagnesian magma - More __________________ than felsic magma. - Most ____________________ igneous rocks. 3. Underground Magma Magma can cool slow or fast depending on ____________ cooling occurs - Intrusive rocks cool very __________________ underground - Result of slow cooling o _______________ (large) grains 4. At the Surface Magma pouring onto the surface is called ____________ - Extrusive igneous rocks cool ________________ - _______________________ grains or none at all Porphyry - Rocks that cool ________ underground and at the _______________ - Results in _____________ and ____________ grains 5. Igneous Families Grouped according to ___________________ _____________________ _________________ is determined where it cools - intrusive or extrusive - Each family can have coarse grained, fine grained or glassy textures - Also can have ______________________ o Vesicles are ________ cavities within the rock Granite family - ______________ magma - ___________ colored - Quartz and Feldspar o Coarse ________________ o Fine ________________ o Glassy ________________ and __________________ Gabbro Family - Mafic magma - _______________ colored - Pyroxene and ________________ o Coarse ________________ o Fine ________________ o Vesicular ________________ Diorite family - Intermediate o Coarse Diorite o Fine Andesite 6. Igneous Intrusions ____________________– a rock mass that forms when magma cools under ground - Dikes - _________________ - _____________________ - Volcanic necks - _____________________ – largest of all plutons, form the cores of most mountains