Life Cycles of Basaltic Magma Mushes: The Dynamic Controls on Unlocking and Mixing

University Of Washington, Seattle WA

Investigators

Abstract

The transport of heat and mass from the Earth's deep interior to the surface by magmatism (volcanism) creates the Earth's crust and strongly conditions the atmosphere and biosphere. However the processes are almost entirely unseen, and the dynamics must be inferred from sparse observations. These observations have converged on a picture for magma systems such that they exist in a mushy, or crystal-rich and quasi-static, state for much of their thermal lifetime. This has been documented in a variety of geological environments from ocean islands and large igneous provinces, to convergent margin volcanic chains, to mid-ocean ridge systems. Paradoxically, it has also been confirmed that these mushes can be rapidly mobilized and complexly mixed, sometimes just prior to eruption. And when the crystal mushes are preserved as large plutonic bodies, they display evidence of complex fluid and granular rheological regimes that co-existed simultaneously. Our aim is to identify the fundamental dynamic templates that produce these reoccurring processes in Nature. We will do this by employing the unification of crystal-chemical data and novel computational fluid dynamics modeling tools to reveal the templates which control of emergence of and character of distinct magmatic episodes. Our field area will be the 1868 lava flows of Mauna Loa, Hawaii, where we will identify distinct populations of magmatic products, and by utilizing the discrete element method computational fluid dynamics approach we can create synthetic populations and identify what the dynamic controls are on their occurance.