12.4

• Magma is the molten rocks inside the volcano.
• Lava is the molten rocks ejected into the surface of the volcano and is the primary product of eruption.
• Quenching is the process when lava freezes.
• Viscosity of lava depends on silica content.
• Basaltic is silica-depleted, very hot, low viscosity when erupted, fast movement on steep slopes.
• Pahoehoe - ropy.
• Aa lava - spiny.
• Pillow - blob.
• Columnar jointing - well formed hexagonal columns perpendicular to the flow.
• Andesitic has intermediate viscosity, cannot flow easily, do not move further than 10km.
• Rhyolitic are silica-enriched and lowest temp they form lava domes.
• Volcaniclastic deposits are large quantities of fragmental igneous debris, include fragments of frozen ejected lava, pre existing volcanic rock blasted apart by an explosive eruption and debris from flank.
• Pyroclastic debris is any volcanic fragments produced directly by eruptions.
• Cinders lapilli are lava fragments with 2-64mm pea to plum suze.
• Bombs are larger fragments.
• Pele's hair are glass filaments which froze from droplets of thin lava.
• Pele's tears are glass droplets of thin lava.
• Erupting lava fountains eject blobs of spatter which can accumulate into spatter cones and spatter ramparts.
• Eruption columns or vertical plumes produce airbone materials that fall down are called our fall deposit.
• Blocks are large fragments.
• Ash tuff are layers of ash formation.
• Extremely large eruptions produce a fluidized cloud of incandescent fragments and gasses called nuée ardente.
• Tephra are unconsolidated volcanic fragments.
• Lahar is a slurry mixture of tephra and water.
• Volcanic volatiles are dissolved fluids released as gasses during eruption (9% magma).
• Degassing are the decrease of pressure that allows vitatiles to come out of solution as magma comes approaches the surface.
• Vesicles are gas bubbles trapped by high viscosity magma.