Cordilleran tectonics

这项研究旨在阐明加拿大科迪勒拉山脉地带的一些形成过程。重点研究了加拿大南部和蒙大拿州北部科迪勒前陆冲断褶皱带的起源和演化，该带是在原始北美和其西缘俯冲带之间的汇聚过程中形成的。逆冲褶皱带由一片片的表壳岩层组成，这些表壳岩层被一种主要是海洋盆地的火山岩拼贴而成的俯冲构造拼贴体从俯冲的原始北美大陆及其西缘剥离出来，这种构造拼贴被称为“山间地体”。这项研究包括编制“恢复的”古地质构造剖面和地图，描绘在逆冲和褶皱之前存在的表壳岩石的位置和形态。三个深沉积盆地(Belt-Purcell、Windermel和Cordilleran miogeclue)将恢复它们之间的原始关系，以及与延伸到Cordillera之下的北美古元古代基底中的深地壳结构的关系。重建将主要基于地质图和平衡的深部结构切片。另外5张1：50,000比例尺地质图，附有构造剖面图和两张新的区域图。将根据现有的实地数据完成深层、平衡的结构部分，以弥合区域中心的关键信息差距。深部地震成像与来自变质岩和火成岩的重磁异常图、地质图、热计时和地质气压数据一起，将制约变形的区域和时间变化以及地壳和岩石圈的深部结构。初步分析表明，该带的累积位移为300公里。这项研究的结果有望阐明加拿大东南部科迪勒拉及其丰富的化石燃料和矿产资源是如何形成的，何时形成的，以及为什么形成的，也可以让许多人知道，他们对落基山脉的迷恋引起了他们对山脉的好奇。

This research aims to elucidate some of the processes involved in the formation of mountain belts as exemplified by the Canadian Cordillera. The focus is on the origin and evolution of the Cordilleran foreland thrust-and-fold belt in southern Canada and northern Montana, which formed during convergence between ancestral North America and subduction zones along its western margin. The thrust-and-fold belt consists of sheets and slices of supracrustal strata that have been scraped off the under-riding ancestral North American continent and its western margin by an over-riding tectonic collage of accreted, mainly ocean-basin, volcanic rocks called "Intermontane terrane". The research involves preparation of "restored" paleogeological structure sections and maps that portray the supracrustal rocks in the locations and configurations in which they existed prior to the thrusting and the folding. Three deep sedimentary basins from which most of the displaced rocks came (Belt-Purcell, Windermere, and Cordilleran miogeocline) will be restored to their original relationships with each other and with the deep crustal structures in the Paleoproterozoic basement of North America that extends under the Cordillera. The reconstructions will be based mainly on geological maps and balanced deep structure sections. Five additional 1:50,000-scale geologic maps, with structure sections and two new regional. deep, balanced structure sections will be completed from available field data to close a critical information gap in the centre of the region. Deep seismic imaging, together with gravity and magnetic anomaly maps, geological maps, and thermochronometric and geobarometric data from metamorphic and igneous rocks will provide constraints on regional and temporal variations in deformation and on the deep crustal and lithospheric structure. Preliminary analyses indicate that the cumulative displacement across the belt is >300 km. The results of this research can be expected to clarify how, when, and why the southeastern Canadian Cordillera and its rich fossil fuel and mineral resources formed, and also to inform the many people whose fascination with the Rockies arouses their curiousity about the mountains came to be.