Subduction zone - Geochemistry I - Lecture Slides, Slides of Geochemistry

Download Subduction zone - Geochemistry I - Lecture Slides and more Slides Geochemistry in PDF only on Docsity! Subduction zone magmatism Docsity.com  Activity along arcuate volcanic island chains along subduction zones  Distinctly different from the mainly basaltic provinces thus far  Composition more diverse and silicic  Basalt generally occurs in subordinate quantities  Also more explosive than the quiescent basalts  Strato-volcanoes are the most common volcanic landform Docsity.com Subduction Products  Characteristic igneous associations  Distinctive patterns of metamorphism  Orogeny and mountain belts Complexly Interrelated Docsity.com Island vs. Continental arc:  Continental arcs have  Thicker lithosphere (deeper melting?/melting of slightly different mantle?)  Thicker crust: possible interactions with preexisting crust/lithosphere  Island arcs are « simpler » as they allow to focus on the primary processes Docsity.com Structure of an Island Arc Figure 16-2. Schematic cross section through a typical island arc after Gill (1981), Orogenic Andesites and Plate Tectonics. Springer-Verlag. HFU= heat flow unit (4.2 x 10-6 joules/cm2/sec) Docsity.com