Testing channel flow: Architecture of the Northern Monashee Mountains, SE Canadian Cordillera

该研究项目是麦吉尔大学、卡尔加里大学和商业资源公司地球科学家之间的合作，旨在详细了解加拿大东南部科迪勒拉山脉莫纳西山脉地壳的结构和构造演化。 这些山脉中的岩石形成了晚前寒武纪裂谷大陆边缘的一部分，在中生代和第三纪的碰撞事件中，大陆边缘因褶皱和逆冲作用而增厚。 它们当时位于中地壳，内部结构在接近熔化的温度下形成。 最近的模拟研究表明，在这些条件下，这些岩石可能会在通道中流入压力较低的地区。 这一直主张为Monashees，并支持整个地区的变质年龄的变化，但它似乎与现有的结构解释冲突。 我们建议在两个暴露良好的山谷最近空出的冰川，与后续的变质和年代学研究，旨在解决这一明显的冲突进行详细的结构研究。 Monashees含有丰富的碳酸岩岩床，是钽和铌的远景。可能由于变形，窗台的厚度沿其长度沿着变化很大。 我们计划中的研究将更好地了解厚度变化的原因，并将有助于勘探经济上可行的矿床。 这一研究对我们理解全球造山带深部地壳的演化具有重要意义，并对研究区域和其他地区的矿产勘探具有直接影响。

This research project, a collaboration between Earth scientists from McGill University, the University of Calgary and Commerce Resources Corporation, is designed to produce a detailed understanding of the structural and tectonic evolution of the crust in the Monashee Mountains of the SE Canadian Cordillera. The rocks in these mountains form part of a late-Precambrian rifted continental margin that was thickened by folding and thrusting during collisional events in the Mesozoic and Tertiary. They were in the middle crust at the time, and the structures within them formed at temperatures close to melting. Recent modelling studies have indicated that under these conditions such rocks may flow in channels into regions of lower pressure. This has been advocated for the Monashees and is supported by variations in metamorphic ages across the region, but it appears to conflict with existing structural interpretations. We propose a detailed structural study in two well-exposed valleys recently vacated by glaciers, with follow-up metamorphic and geochronological studies, aimed at resolving this apparent conflict. The Monashees contain abundant carbonatite sills, which are prospective for tantalum and niobium. The sills vary significantly in thickness along their lengths, probably due to the deformation. Our planned research will provide a better understanding of the causes of thickness variation and will aid the exploration for economically viable deposits. This study has implications for our understanding of the evolution of the deeper crust in orogens worldwide, and direct bearing on mineral exploration in the region of study and elsewhere.