CAS ES 105 Lecture Notes - Lecture 4: Igneous Rock, Batholith, Volcanism

• School: Boston University
• Department: Earth Sciences
• Course: CAS ES 105
• Professor: Lawford Anderson

Document Summary

The earth breathes out through its volcanoes and in through its oceans and plants. Key process of earth atmosphere and crust formation: all from the mantle. Magmatism on earth: the major plate boundaries and active volcanoes of the world; also intralplate hot spots (hawaii, fiji, yellowstone) Igneous extrusion (lava): volcanic rock (basalt) (reaches out the surface to cool) Igneous intrusion (magma): granite (cools inside the earth) The largest plutons (with exposed surface areas > 40 square miles) are called batholiths; plutons with a smaller surface are called stocks. Intrusive rocks can crosscut country rocks structures and strata and be termed discordant (dikes or batholith(large surface area)) Obsidian: glassy, volcanic, silic, and rapid quenching. Pyroclastic: violent breakage during explosive eruption, include both small (volcanic ash) and larger pieces (cinders) of the volcano blown apart during its eruptions. Phaneritic (visible crystals: plutonic, slow crystallization (slow cooling)