Wed 27th March@ noon, Rm 312.222

Abstract:

Modern views of igneous systems are moving increasingly away from the long-standing large magma chamber paradigm towards a more nuanced concept of transcrustal magmatic mushes, wherein the dominant mechanism of igneous differentiation is percolative reactive flow, rather than traditional crystal settling. The melts that populate these mushy systems have significantly higher dissolved volatile (H2O, CO2) contents than previously assumed, with important consequences for their transport properties and chemical evolution. In this talk I will review the evidence for mushy magmatic systems and outline recent numerical and petrological models of dynamic transcrustal magma systems. I will discuss the implications for volcanism, magma chemistry and hydrothermal ore formation with reference to a number of studies of active volcanic systems in the Altiplano (Bolivia), Cascades (USA) and Lesser Antilles.

Short bio:

Jon Blundy is an igneous petrologist, with interest in all things magmatic, from magma generation in the crust and mantle to trace element geochemistry, active volcanism and hydrothermal mineralisation. He approaches these topics through a combination of field observations, thermodynamics, microbeam analysis, and high pressure-temperature experiments. He is based at the University of Bristol (UK), where he has been since 1989. He has held visiting positions at the universities of Oregon and Nagoya (Japan), California Institute of Technology and, currently, UWA. He has received a number of awards for his research, including the Ted Ringwood Medal of the European Association of Geochemistry (2016), and the Bigsby (2005) and Murchison (2016) Medals of the Geological Society. He was elected Fellow of the Royal Society in 2008.