Tectonic Evolution of the Virgin-Beaverdam Extensional Breakaway Zone, Nevada, Arizona and Utah

岩石圈变形的物理学主要是一个通过流变性将应力和应变联系在一起的连续介质问题。在理解物理过程方面的进展包括直接测量地球材料流变性的实验室实验，以及通过良好的岩石圈变形自然实验。该项目旨在确定岩石圈在伸展环境中对极端构造卸载的响应。一个潜在的研究区位于维尔京山脉科罗拉多高原西缘，在那里，中中新世大规模的伸展构造作用沿着自下向西的正断层将原本毗邻高原的地壳碎片向西输送了50-100公里。在这些被运送的碎片之后，高原边缘的伸展“分离带”经历了至少5公里的抬升，甚至可能多达20公里。这项提案将通过构造制图和实验室流体包裹体研究，详细研究金巴特区块，以确定内部破坏的程度以及旋转区块的差异抬升和侵蚀程度。结果将直接关系到该地区是否适合确定均衡隆升在大陆伸展中的作用，以及总体上岩石圈的伸展响应。

The physics of lithospheric deformation is primarily a continuum problem relating stress and strain through rheological properties. Progress towards understanding physical processes involves laboratory experiments that directly measure rheological properties in earth materials, and through well-posed natural experiments of lithospheric deformation. This project is aimed at determining the response of the lithosphere to extreme tectonic unloading in an extensional environment. A potential study area is located along the western margin of the Colorado Plateau in the Virgin Mountains, where large-scale mid-Miocene extensional tectonism along down-to-the-west normal faults has transported crustal fragments originally adjacent to the plateau 50-100 km to the west. In the wake of these transported fragments the extensional "breakaway zone" at the edge of the plateau experienced at least 5 and possibly as much as 20 km of uplift. This proposal will examine the Gold Butte block in detail, by structural mapping and laboratory fluid inclusion studies, to determine the degree of internal disruption and the amount of differential uplift and erosion across the rotated block. Results will bear directly on the appropriateness of this area determining the role of isostatic uplift in continental extension, and also on extensional response of the lithosphere generally.