Rheological behaviour of the crust

不列颠哥伦比亚省西部是由海洋地壳的持续俯冲在边缘附近形成岩浆岩（类似于今天太平洋板块在西科迪勒拉山脉下的俯冲以及随之而来的北美边缘火山的聚集）和大块岩石碎片（“地体”）向边缘的增加而形成的。一般来说，当地面碰撞时，大部分位移被相对狭窄的高应变带所吸收——例如，考虑圣安德烈亚斯断层。该提案的目的有两个：(1)对这些狭窄区域的岩石变形机制进行限制，确定这些区域的寿命，并确定这些剪切带的范围和几何形状；(2)对不列颠哥伦比亚省中西部的碰撞机制进行更好的时间限制和理解。这项拟议的研究结合了在碰撞区域发现的变形岩石的现场测绘，从现场收集的岩石的微观结构分析，以及地质年代学（岩石定年），以更好地了解岩石在高应变区如何变形的机制。这个提议的一个较小的方面涉及实验岩石变形，以及我们如何使用从实验室收集的应力-应变数据来更好地理解地球上发生的过程。

Western British Columbia was constructed by continued subduction of oceanic crust creating magmatic rocks near the margin (similar to what is happening today with the subduction of the Pacific plate beneath the western Cordillera and the consequent build up of volcanoes on the north American margin) and by the accretion of large fragments of rock ('terranes') to the margin. Generally, when terranes collide much of the displacement is taken up by relatively narrow zones of very high strain - consider, for example, the San Andreas Fault.  The purpose of this proposal is twofold: (1) To place constraints on the mechanisms of how rocks deform in these narrow zones, to determine how long-lived these zones are, and to determine the extent and geometry of these shear zones, and  (2) to place better timing constraints and understand the mechanisms that accommodated collision in west central British Columbia. This proposed research combines field mapping of deformed rocks found in collisional regimes, with microstructural analysis of rocks collected from the field, with geochronology (dating the rocks) to better understand the mechanisms of how rocks deform in zones of high strain. A smaller aspect of this proposal deals with experimental rock deformation and how we can use stress-strain data collected from the lab to better understand processes that occur in the Earth.