Welding of hot pyroclasts in volcanic environments

在这个项目中，实地工作将在大加那利岛（西班牙）和潘泰莱里亚（意大利）的典型实地地点进行，并可能在斯内克河平原（美国）扩展实地工作。这些地点都有大量不同体积的焊接烟灰岩，这些烟灰岩是由不同规模的火山喷发沉积而成，其成分范围从流纹岩到phonolite不等。对这些烧灰进行详细的纹理研究，将使学生对焊接和自然流变的条件提出假设。接下来，学生将在杜伦大学的热实验室中使用一系列自制岩浆成分，在剪切应力、负载和结晶窗口下进行焊接实验，复制这些纹理。最后，学生将精通缩放模型开发和模型应用，以便解释他们的结果并概括/升级到岩浆条件。综上所述，这些研究路线将使学生在理解火山环境中的火山碎屑焊接和火山碎屑密度流中焊接的火成岩沉积方面取得实质性进展。

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.