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Laser micro-chemical mapping of volcanic crystals: new insights into eruption triggers

Event Type: 
Seminar
Event Date: 
28 Mar 2018
Venue: 
ASE 3D Viz Laboratory Room (N2-B1c-16c)
Speaker: 
Teresa Ubide
About the speaker: 

Teresa Ubide is a Lecturer in Igneous Petrology/Volcanology at the University of Queensland (Brisbane, Australia). She completed her BSc, MSc and PhD studies at the University of Zaragoza (Spain, 2013) and VU University Amsterdam (The Netherlands), and held a Research Fellowship at Trinity College Dublin (Ireland, 2014-2016) before moving to Australia in July 2016. She combines detailed petrological observations with state-of-the-art analytical techniques to investigate magmatic histories. She is particularly interested in constraining the processes that initiate volcanic eruptions on Earth and other planetary bodies.

About the event: 

Geochemical imaging with LA-ICP-MS (laser ablation inductively coupled mass spectrometry) has rapidly developed in the last few years as an in-situ, high resolution technique able to visualize the distribution of trace elements in geological materials. LA-ICP-MS trace element maps have the potential to reveal complexities in natural processes that are not apparent under the microscope or using microbeam spot analyses. Investigation of early crystals from Mt Etna volcano (Sicily) show that magmatic processes leading to eruption are recorded in the trace element zoning of clinopyroxene. Results link the increase of volcanic activity in the past decades to recharge of the plumbing system with new primitive magma. Thermobarometric and timescale constraints indicate ascent of magma from ca. 10 km to the surface in ca. 2 weeks. Improved constraints on the movement of magma preceding past eruptions could advise future volcano monitoring efforts in relation to the origin of seismic or deformation signals and the time available for hazard evaluation and emergency planning.

LA-ICP-MS chromium map of a clinopyroxene crystal from the 2001 eruption at Mt Etna, Sicily, which is the most active volcano in Europe. The colour scale reflects concentration in parts per million, with warmer colours representing higher concentrations. Note the increase in Cr concentrations close to the rim, recording the episode of mafic recharge that triggered the eruption. The photomicrograph on the left (transmitted light, crossed polarisers) provides context. Modified from Ubide and Kamber (2018, Nature Communications).