CEE 437 Rocks! Thomas Doe Outline     Igneous Rocks Sedimentary Rocks Metamorphic Rocks Rock Identification Lab Rock Cycle Crystallization at depth or extrusion at surface Igneous Rocks Sediments Lithification Magma Burial, metamorphism, recrystallization Weathering, Erosion Melting Metamorphic Rocks Burial, metamorphism, recrystallization Sedimentary Rocks Northwest Igneous and Metamorphic Rocks Cascade Volcanoes (recent) Cascade Batholiths (Felsic, CretMiocene) Columbia River Basalts (miocene) Recent Basaltic Volcanism (Newberry Crater) Snake River Basalts (pliocene) Yellowstone Region Acidic Volcanics (Pleistocene to recent) Geologic Settings for Igneous Rocks  Oceanic  Hi Fe, Mg, Ca, low Si  basalt, gabbro  Continental  Hi Si, Na, K  granite, rhyolite, andesite Igneous Origins  Intrusive  Batholithic or plutonic: phaneritic  Dikes or sills that chill rapidly: aphanitic  Extrusive  deposition as melt (lava)  pyroclastic tuff  tephra  pyroclastic flows  Identifying Igneous Rocks  Chemistry  Acidic: Basic (more Si, less Si)  Texture  Aphanitic: crystals not visible  Phaneritic: made of visible crystal components  Porphyritic: Larger crustals in aphanitic or phaneritic ground mass Igneous Rock Classification Acidic, Felsic Basic, Mafic Ultramafic SERPENTINITE Magma Generation on Continental Margins Basic Metamorphic Types    Quartz Sandstone → Quartzite Limestone, Dolomite → Marble Shale →  Slate — cleavage, no visible xl’s  Phyllite — foliation, mica sheen but xl’s not visible  Schist — clear foliation, visible mica  Gneiss — like granite but with foliation/gneissosity  Basalt → greenschist, amphibolite Non-foliated Metamorphic Rocks    Sandstone —> Quartzite Limestone —> Marble Dolomite —> Dolomitic Marble Foliated Metamorphic Rocks      Shale/Mudstone Slate Phyllite (Greek for leaves e.g phyllo dough) Schist Gneiss Origin of Foliation (gneissosity, schistosity) Engineering Properties   Anisotropy of strength and elastic properties Preferred failure on foliation Slate Phyllite Schist Chlorite Schist Gneiss Banded Gneiss Metamorphic Grade Subduction-Zone Metamorphism Metamorphism at Continental Collisions Contact Metamorphism