Overview: The Subduction Factory Mini-lessons
Chris Kincaid, Bob Stern, Sarah Penniston-Dorland, Ben Edwards
- The relationship of magma output and composition to forcing functions such as convergence rate, plate age, and sedimentary input.
- The cycling of volatiles from the slab to the mantle wedge and ultimately to either the crust and surface reservoir or back into the deep mantle.
- The production rate of arc crust.
The Central American and Izu-Bonin-Mariana magmatic arcs were chosen during open meetings by the geoscientific community to be the foci for a wide range of geochemical and geophysical studies because they represent two different types of factories: one whose input is old oceanic crust (IZB) and the other young oceanic crust (CAVA).
To help integrate important results from SubFac into geoscience curricula, we have developed three mini-lessons intended to guide student exploration of heat and mass inputs and outputs of the Subduction Factory:
Subfac: Slab temperatures control melting in subduction zones, what controls slab temperature? - this module is a hands-on demonstration of advection and diffusion of heat in subduction zones that uses analog models to investigate their controls on slab thermal evolution and relationships to melting and Metamorphism.
Subfac: Subduction zone metamorphism - this module introduces students to subduction zone metamorphism by examining what happens to basalts during subduction, calculating P-T-t paths, and comparing the paths to thermal model predictions. This module also provides an opportunity for instructors to obtain teaching samples of fresh Mid-Ocean Ridge Basalt, greenstone, blueschist, and eclogite.
Subfac: Central American arc volcanoes, petrology, and geochemistry - this module uses basic concepts in igneous petrology, from hand specimen identification of lavas to major element geochemistry, to teach students how to investigate processes that lead to the production of petrologic diversity in subduction zones using two Central American arc volcanoes as examples.