Welding of hot pyroclasts in volcanic environments

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In this project, fieldwork will be undertaken at type field-localities in Gran Canaria (Spain) and Pantelleria (Italy), and with possible extension fieldwork in the Snake River Plain (U.S.A.). These sites all host extensive welded ignimbrites of variable volume, deposited from eruptions of different magnitude, as well as covering the compositional range from rhyolite to phonolite. Detailed textural work on these ignimbrites will allow the student to pose hypotheses about the conditions of welding and rheomorphism in nature. Next, the student will replicate these textures using welding experiments under shear stresses, under load, and in the crystallisation window, using a range of homemade magma compositions in the hot-labs at Durham University. Finally, the student will become proficient with scaled model development and model application in order to interpret their results and to generalise/upscale to magmatic conditions. Taken together, these lines of enquiry will allow the student to make substantial steps forward in our understanding of pyroclast welding in volcanic environments and the deposition of welded ignimbrites from pyroclastic density currents.