Welding of hot pyroclasts in volcanic environments

在该项目中，将在大加那里亚(西班牙)和潘特莱里亚(意大利)的典型实地考察地点进行实地考察，并可能在蛇河平原(美国)进行实地考察。这些遗址都有不同规模的喷发沉积的大量焊接的辉绿岩，覆盖了从流纹岩到声岩的成分范围。对这些点火砖进行详细的质地研究将允许学生提出关于焊接条件和自然界中的流变性的假设。接下来，学生将在达勒姆大学的热实验室中，使用一系列自制的岩浆成分，在剪切力、载荷和结晶窗口下进行焊接实验，复制这些纹理。最后，学生将精通比例模型开发和模型应用，以解释他们的结果，并概括/升级到岩浆条件。综上所述，这些问题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褐沸石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.