European Union of Geosciences

Arthur Holmes Medal

Charles Langmuir For fundamental contributions to the understanding of the geochemistry of mantle melting.

Charlie Langmuir has been an inspiration to a generation of petrologists, geochemists and people generally interested in how the mantle melts. He took the agenda out of the experimental presses and into the geochemistry lab. Together with a string of excellent graduate students, he has made seminal contributions to melting at mid-ocean ridges, island arcs and even the crystallisation of melts.

Charlie has made difficult things look easy. He turned phases diagrams into a few key binary plots. The global syntheses of MORB and arc lavas by his outstanding students Emily Klein and Terry Plank put awesome simplicity into the understanding of these primary regions of melt production. With Jennifer Reynolds he focussed on the changing length-scales on ridge segment variability to piece together a remarkable high resolution image of sub-ridge magmatic plumbing, and that ultimately provides key evidence for the nature of melt transport beneath ridges.

Together with Jeff Ryan he mapped out the basic systematics of B and Li in the magmatic environment, and with Dan Miller he was the first clearly to document the anomalous role of Pb during subduction (a key to understanding isotopic signatures of planetary evolution). Illustrating the beautiful coherence of trace element abundances in subducted sediments was the centre piece of Terry Plank's thesis which enabled Terry and Charlie to benchmark recycled sediment fluxes and develop the now largely accepted two component model for arc lava genesis.

Charlie has a treasure trove of unpublished data and ideas, that haven't quite yet made his grade for publication but sometimes glitteringly surface in discussion. Furthermore, he has made important practical contributions in the lab and at sea. He is an outstanding geochemist who has advanced global petrological problems with great practical nous but crucially with a remarkable intuition of how the periodic table behaves in the silicate Earth.