Geo (6) PDF - Igneous Rock Textures

## Subject: Texture ### Factors of crystal size: - Amount of dissolved gases - Cooling rate ## Subject: Plutonic ### Pegmatite texture: - It's formed in the final stages of crystallization of magma which water vapor and gases - Very coarse ## Subject: Volcanic ### Fine grained texture: - Size is...

## Subject: Texture ### Factors of crystal size: - Amount of dissolved gases - Cooling rate ## Subject: Plutonic ### Pegmatite texture: - It's formed in the final stages of crystallization of magma which water vapor and gases - Very coarse ## Subject: Volcanic ### Fine grained texture: - Size is small - Ex: Bazalet rock ### Glassy texture: - No crystals - Very rapid cooling - Ex: Obsidian ### Vesicular texture: - Evaporation of gases from magma during crystallization - Ex: Pumic, Scoria ### Amygdaloidal texture: - Deposition of magma in voids - Ex: Amygdaloidal ## Subject: Hypabyssal ### Medium grained texture ### Porphyritic Volcanic - Cools above ground ## Subject: Chemical composition ### Acidic - Felsic / non-ferromagnesium silicate - Si 65-80 - Rich (K-Feldspar, Neplagi, Mica, Qtz) - High viscocity - Low density - Light color except 10% dark - Ex: Granite ### Basic - Mafic Rock Perro magnesiam silicate - Si 45-52 - Rich Olivine - Dark color - High density - Ex: Basalt - Pyroxene ## Subject: Intermediate rock - Si 52-65 - Color dark to light - Biotite - Pyroxene - Amphibole - Na plagi - Ex: Andesite ## Subject: Ultramafic rock - Si <45 - Rich (Olivine, Pyroxene) - Ex: Peridotite ## Subject: Mineralogical ### Felsic - Non-ferro-Mg - Quartz - Feldspar - SiO-K-Na - Ex: Granite ### Mafic - Perro-Mg - Olivine - Pyroxene - Amphibole - Biotite