Types of Igneous Plutons Volcano Dikes Laccolith Sills p.140-141d Volcanic Pipe Original artwork by Gary Hincks Dikes Batholith Fig 6.08b Stephen Marshak Types of Igneous Plutons Volcano Dikes Laccolith Sills p.140-141d Volcanic Pipe Original artwork by Gary Hincks Dikes Batholith Fig 6.10 W W Norton Fig 6.11a Stephen Marshak Fig 6.11de Paul Hoffmann Fig 6.18 W W Norton Plate Tectonic Setting as a Context For Magma Generation 1) Mantle plumes & hot-spots 3) Divergent 4) Melting of 2) Convergent margins:Melting lithosphere & margins: of lithosphere crust beneath Subduction of along ocean continental rift slabs of spreading zones lithosphere centers Fig 6.14ab W W Norton Ways To Melt Rock: Fig Lower pressure 6.04a in the mantle (e.g along W W Norton divergent margins) Fig 6.03 W W Norton “Decompression melting” Rock moving from point A to point B in the mantle sees a decrease in pressure Ways To Melt Rock Fig 6.04a Raise the temperature of the surrounding rock W W to melting temperature Norton Ways To Melt Rocks Fig 6.04c Add water! W W Norton Fig 6.04b W W Norton Making Silica-rich Magmas Fig 6.05a W W Norton 1) Partial melting of mafic, or ultramafic rocks Making Silica-rich Magmas: 2) Assimilation of siliceous “country rocks” Fig 6.09ab W W Norton Making Silica-rich Magmas Fig 6.05c W W Norton 3) Fractional crystallization & gravity settling of early formedmafic minerals [...]... Raise the temperature of the surrounding rock W W to melting temperature Norton Ways To Melt Rocks Fig 6.04c Add water! W W Norton Fig 6.04b W W Norton Making Silica-rich Magmas Fig 6.05a W W Norton 1) Partial melting of mafic, or ultramafic rocks Making Silica-rich Magmas: 2) Assimilation of siliceous “country rocks Fig 6.09ab W W Norton Making Silica-rich Magmas Fig 6.05c W W Norton 3) Fractional