Concepts for lower to middle crustal magma ascent are mainly derived from crustal sections that show the time-integrated processes of magma storage, evolution, and transport through the crust, thus limiting our ability to track individual batches of ascending magma. However, understanding magma transport of single batches in the lower and middle crust and their linkage to the shallow plumbing system will not only help interpreting the exposed time-integrated crustal record, but also extend our ability to forecast volcanic behavior that is ultimately fed from mantle-derived magmas.

NSF-supported project: EAR1426820

Mantle signals in arcs: Transport models from geochemistry and seismicity

In a multidisciplinary approach that combines elemental diffusion modeling of zoned primitive phenocrysts, thermal modeling of dike propagation, and collaboration with colleagues in seismology, I am working towards quantifying how fast magma transits mature arc crust. I am comparing results from various arcs (Central America, Andes, Aleutians, Tonga) to identify the controls that permit fast (< 1 yr) ascent from the Moho to the surface.

E.g., at Irazú volcano in Costa Rica I have shown that despite interaction with an extensive shallow plumbing system some crystals maintain their primitive mantle-like character and provide access to the processes at Moho-depth (~35 km in the case of Irazú).

Relevant publication:

Ruprecht P., Plank T. (2013) Feeding andesitic eruptions with a high-speed connection from the mantle.  Nature 500: 68-72, doi:10.1038/nature12342.

Photos: Left, close up of a intra-crater tephra deposit from the 1963-65 eruption of Irazú volcano. Irazu volcano in Costa Rica had two historic eruptions, 1723 CE and 1963-65 CE. We use the well preserved tephra deposits and phenocrysts therein to study Moho to surface ascent time scale. Bottom, olivine phenocryst from the 1963-65 eruption storing the presence of distinct mantle melts in its zonation pattern and recording rapid Moho to surface transport.