Earthquakes, metamorphism, and melting: understanding the behaviour and evolution of mountain ranges

尽管是地球上最壮观的地质特征之一，但围绕着控制山脉的行为、大小、形状和随时间演变的过程，争论仍然很激烈。具体问题涉及地壳和上地幔的物质特性，它们如何随时间变化，以及它们如何受到变质作用和熔融作用的影响。这些材料的特性反过来又控制着山脉的大规模行为和变形，从而控制着它们的大小、形状和随时间的演变。通常，以前的研究使用单独的方法来解决这些问题。相比之下，该项目将通过整合地震研究（使用地震学、大地测量学和实地考察）、变质作用（使用实地考察、岩石学和相平衡建模）、融化（使用火山岩地球化学）和动态建模来获得新的见解。因此，将有可能对控制造山过程和演变的因素以及它们之间的联系取得连贯的全面了解。该项目将研究至少两个山脉，从东欧、中东和亚洲的一系列令人兴奋的潜在目标中选择（可以通过联系主管进行更详细的讨论）。现今的变形将利用地震地震学、卫星大地测量学和活动断层的实地研究来确定。变质岩和火成岩岩石学将用于探索造山的历史，以及深度的热结构（从变质岩的压力-温度-时间历史和火成岩的化学和年龄）。然后，这些观测结果将通过使用动态模型来综合研究构造、变质作用和融化之间的相互作用，以便了解控制山脉行为和演化的因素。学生将首先进行实地考察，收集火成岩和变质岩样品，并对保存在地貌中的活动断层进行实地观察。这些样品将用于岩石学分析，以及变质相平衡和火成岩成分的建模（例如Weller et al， 2013）。同时，学生将使用地震地震学和卫星大地测量学对目标区域的当前变形做出新的见解（例如Copley等人，2015年）。然后，学生将构建机械和热模型，将这些不同的新观察结果结合起来，全面了解该范围的材料特性、变形和热结构（例如Copley等人，2011）。因此，改变这些模型的参数，并研究与所有可用观察结果一致的因素，将揭示控制材料特性和范围行为的可能因素的相对重要性（例如温度，变质相变化，熔化，断层强度和再激活）。

Despite being some of the most spectacular geological features on Earth, debate still rages surrounding the processes that control the behaviour, sizes, shapes, and evolution through time of mountain ranges. Specific questions concern the material properties of the crust and upper mantle, how they vary through time, and how they are affected by metamorphism and melting. These material properties in turn control the large-scale behaviour and deformation of mountain ranges, and therefore control their sizes, shapes, and evolution through time. Typically, previous studies have used individual methods in isolation to address these questions. In contrast, this project will make new insights by integrating research into earthquakes (using seismology, geodesy, and fieldwork), metamorphism (using fieldwork, petrology, and phase equilibria modelling), melting (using the geochemistry of volcanic rocks), and dynamic modelling. It will therefore be possible to attain a coherent overall understanding of the factors that control the processes and evolution of mountain building, and how they are linked.The project will study at least two mountain ranges, chosen from a list of exciting potential targets in Eastern Europe, the Middle East, and Asia (which can be discussed in more detail by contacting the supervisors). The present-day deformation will be established using earthquake seismology, satellite geodesy, and fieldwork studies of active faulting. Metamorphic and igneous petrology will be used to probe the history of mountain-building, and the thermal structure at depth (from pressure-temperature-time histories of metamorphic rocks and the chemistry and ages of igneous rocks). These observations will then be synthesised by using dynamic models to investigate the interplay between tectonics, metamorphism, and melting, in order to understand the factors that control the behaviour and evolution of mountain ranges.The student will begin by conducting fieldwork to collect igneous and metamorphic samples, and make field observations of active faulting preserved in the geomorphology. The samples will be used for petrological analysis, and the modelling of metamorphic phase equilibria and igneous compositions (e.g. Weller et al, 2013). In tandem, the student will use earthquake seismology and satellite geodesy to make new insights into the present-day deformation of the target regions (e.g. Copley et al, 2015). The student will then construct mechanical and thermal models to combine these diverse new observations into an overall understanding of the material properties, deformation, and thermal structure of the ranges (e.g. Copley et al, 2011). Varying the parameters of these models, and investigating which are consistent with the full range of available observations, will therefore reveal the relative importance of the possible factors that control the material properties and behaviour of the ranges (e.g. temperature, metamorphic phase changes, melting, fault strength and reactivation).