Collaborative Research: A Late Cenozoic Record of Restraining Bend Initiation and Evolution along the Denali Fault at Mount McKinley, Alaska

该项目的目标麦金利山约束弯曲的德纳里断层在阿拉斯加，以研究之间的联系，构造滑动率和区域折返率和约束弯曲如何形成和演变的应变分区的转换压力系统。北美最高的山峰麦金利山（6，196米）位于德纳里断层的17度弯曲的内侧。德纳里断层以北，在这个弯曲的外侧，最高峰是彼得圆顶（3，221米），海拔迅速下降，远离德纳里断层，向北不到15公里的加积盆地。这种地形的不对称性表明，强烈的结构控制当地折返模式，这种抑制弯曲一直是区域造山发展的几百万年的主要控制。该研究将采用多热时计方法，结合对断层模式和滑动速率的新构造/结构分析，限制沿着麦金利山限制弯曲的剥露速率和时间。研究人员将采用放射性碳、光释光和原位陆地宇宙成因核素表面暴露测年技术，为该研究区域的主要变形地貌提供年龄控制。此外，从这项研究的见解将比较复杂的断层几何形状的演变沿着其他走滑断层和认识的短暂和持续的隆起/折返现象在地质record.Major陆内走滑断层在世界各地的断层几何形状在相对较短的距离内表现出突变，往往发生在断层段之间的弯曲或跨越区。这些复杂断层几何形状的区域通常与断层附近的显著隆起或沉降有关。在这些复杂的断层带中，理解水平位移如何沿更广泛的走滑系统沿着划分为水平和垂直分量是构造学研究的一个持续的焦点。特别地，收缩区（即，约束弯曲），其由断层几何形状沿着走滑断层的变化引起，需要邻近断层的显著变形，以使地壳继续沿着沿着长期水平运动的路径。因此，这些区域似乎会朝着一个笔直的断层段发展：然而，限制性弯曲仍然存在。为德纳里断层和邻近断层开发新的滑动速率数据将为现代构造框架提供关键见解，并限制拟议地壳块体的潜在边界。此外，从这项研究的见解将：1）允许比较的结构复杂性沿着其他走滑断层，如圣安德烈亚斯和阿尔卑斯山断层; 2）有助于进一步了解地壳块体如何在大陆地壳广泛的变形带内相互作用; 3）帮助认识地质记录中的短暂和持续的隆升/折返现象。研究小组将与阿拉斯加州费尔班克斯的分水岭学校的教育工作者密切合作，制定教育计划和材料，通过基于地方的教育培养学生对科学的兴趣。通过与德纳利国家公园和保护区工作人员的密切合作，将促进通过该项目取得的科学进展的交流。由于许多以前未知的断层发生在这个地震活跃区，这项研究的结果将有助于显着的区域地震危险性评估。

This project targets the Mount McKinley restraining bend of the Denali fault in Alaska in order to examine the linkages between structural slip rates and regional exhumation rates and how restraining bends can form and evolve in a strain-partitioned transpressional system. The highest mountain in North America, Mount McKinley (6,196 m), is situated on the inside of a 17 degree bend in the mapped trace of the Denali fault. North of the Denali fault, on the outside of this bend, the highest peak is Peter's Dome (3,221 m) with elevations rapidly decreasing away from the Denali fault to an aggradational basin less than 15 km to the north. This topographic asymmetry suggests a strong structural control on local exhumation patterns and that this restraining bend has been a primary control on regional orogenic development for several million years. The study will apply a multi-thermochronometer approach to constraining exhumation rates and timing along the Mount McKinley restraining bend in conjunction with a neotectonic/structural analysis of fault patterns and slip rates. The researchers will employ radiocarbon, optically stimulated luminescence, and in-situ terrestrial cosmogenic nuclide surface exposure dating techniques to provide age control for the major deformed landforms in this study area. Furthermore, insights from this study will be compared to the evolution of complex fault geometries along other strike-slip faults and the recognition of transient and persistent uplift/exhumation phenomena in the geologic record.Major intracontinental strike-slip faults around the world exhibit abrupt changes in the fault geometry over relatively short distances, often occurring as bends or step-over zones between fault segments. These zones of complex fault geometry are often associated with significant uplift or subsidence adjacent to the fault. Understanding how the horizontal displacement along the broader strike-slip system is partitioned into horizontal and vertical components in these complex fault zones is an ongoing focus of research in tectonics. In particular, contractional zones (i.e., restraining bends) that result from a change in fault geometry along a strike-slip fault require significant deformation adjacent to the fault for the crust to continue along the path of long-term horizontal motion. Therefore, it would seem that these zones would evolve toward a straight fault segment: yet restraining bends persist. Developing new slip rate data for the Denali fault and adjacent faults will provide key insights into the modern tectonic framework and constrain potential boundaries of proposed crustal blocks. Furthermore, insights from this study will: 1) allow comparison to the structural complexities along other strike-slip faults such as the San Andreas and Alpine faults; 2) help further understanding of how crustal blocks interact within broad deforming zones of continental crust 3) aid the recognition of transient and persistent uplift/exhumation phenomena in the geologic record. The research team will work closely with educators at the Watershed School in Fairbanks, Alaska, to develop educational plans and materials to foster student interest in science through place-based education. The communication of the scientific advances made through this project will be promoted through close collaboration with Denali National Park and Preserve staff. With numerous previously unknown faults occurring in this seismically-active region, results from this study will contribute significantly to regional seismic hazard assessments.