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

合作研究：阿拉斯加麦金利山德纳里断层沿新生代抑制弯曲起始和演化的记录

• 批准号: 1249885
• 负责人: Jeff Benowitz
• 金额: $ 19.4万
• 依托单位: University of Alaska Fairbanks Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-06-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1249885&HistoricalAwards=false
• 关键词: Collaborative; Research; Late; Cenozoic; Record

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.

该项目以阿拉斯加德纳里断层的麦金利山约束弯曲为目标，以研究构造滑移率和区域折返率之间的联系，以及约束弯曲如何在应变分区压压系统中形成和演化。北美最高的山峰麦金利山 (6,196 m) 位于德纳利断层地图上 17 度弯曲的内侧。德纳利断层以北，在该弯曲处的外侧，最高峰是彼得圆顶 (3,221 m)，海拔从德纳里断层开始迅速下降，直至以北不到 15 公里处的一个沉积盆地。这种地形不对称表明对局部折返模式的强烈结构控制，并且这种限制性弯曲一直是数百万年来区域造山运动发展的主要控制因素。该研究将应用多温度计方法来约束沿麦金利山限制弯曲的折返速率和时间，并结合断层模式和滑动速率的新构造/结构分析。研究人员将采用放射性碳、光激发光和原位陆地宇宙成因核素表面暴露测年技术，为本研究区域的主要变形地貌提供年龄控制。此外，本研究的见解将与其他走滑断层沿线的复杂断层几何形状的演化以及地质记录中短暂和持续的隆起/折返现象的识别进行比较。世界各地主要的陆内走滑断层表现出突然的变化在相对较短距离的断层几何形状中，通常以断层段之间的弯曲或跨步区域的形式出现。这些具有复杂断层几何形状的区域通常与断层附近的显着隆起或沉降有关。了解这些复杂断层带中更广泛的走滑系统的水平位移如何划分为水平和垂直分量是构造学研究的持续焦点。特别是，由于沿走滑断层的断层几何形状变化而产生的收缩区（即限制弯曲）需要在断层附近发生显着变形，以便地壳继续沿着长期水平运动的路径。因此，这些区域似乎将演化为直断层段：但限制性弯曲仍然存在。开发德纳利断层和邻近断层的新滑动率数据将为了解现代构造框架提供重要见解，并限制拟议地壳块的潜在边界。此外，这项研究的见解将：1）可以与其他走滑断层（例如圣安德烈亚斯断层和阿尔卑斯断层）沿线的结构复杂性进行比较； 2) 帮助进一步了解地壳块如何在大陆地壳的广泛变形区内相互作用 3) 帮助识别地质记录中短暂和持续的隆起/折返现象。研究团队将与阿拉斯加费尔班克斯分水岭学校的教育工作者密切合作，制定教育计划和材料，通过就地教育培养学生对科学的兴趣。通过与德纳利国家公园和自然保护区工作人员的密切合作，将促进该项目所取得的科学进步的交流。由于该地震活跃地区存在许多以前未知的断层，这项研究的结果将对区域地震危险性评估做出重大贡献。

项目成果

Corrigendum: Stereovision Combined with Particle Tracking Velocimetry Reveals Advection and Uplift Within a Restraining Bend Simulating the Denali Fault

勘误表：立体视觉与粒子跟踪测速相结合揭示了模拟德纳利断层的约束弯曲内的平流和隆升

• DOI: 10.3389/feart.2019.00253
• 发表时间: 2018-10
• 期刊: Frontiers
• 影响因子: 1.2
• 作者: Toeneboehn, K.;Cooke, M.;Bemis, S.;Benowitz, J.
• 通讯作者: Benowitz, J.

Long distance plutonic relationships demonstrate 33 million years of strain partitioning along the Denali fault

长距离深成关系证明了德纳里断层沿线 3300 万年的应变分配

• DOI: 10.1111/ter.12555
• 发表时间: 2021-08-24
• 期刊: Terra Nova
• 影响因子: 2.4
• 作者: S. Regan;J. Benowitz;T. Waldien;M. Holl;S. Roeske;P. O’Sullivan;P. Layer
• 通讯作者: P. Layer

A plutonic brother from another magma mother: disproving the Eocene Foraker‐McGonagall pluton piercing point and implications for long‐term slip on the Denali Fault

来自另一个岩浆母体的深成体兄弟：反驳始新世福勒克麦格教授的深成体穿透点及其对德纳里断层长期滑移的影响

• DOI: 10.1111/ter.12437
• 发表时间: 2019-10
• 期刊: Terra Nova
• 影响因子: 2.4
• 作者: Regan, Sean P.;Benowitz, Jeff A.;Holland, Mark E.
• 通讯作者: Holland, Mark E.

Cretaceous to Miocene magmatism, sedimentation, and exhumation within the Alaska Range suture zone: A polyphase reactivated terrane boundary

阿拉斯加山脉缝合带内的白垩纪至中新世岩浆作用、沉积和折返：多相重新激活的地体边界

• DOI: 10.1130/ges02014.1
• 发表时间: 2019-06
• 期刊: Geosphere
• 影响因子: 2.5
• 作者: Trop, J.;Benowitz, J.
• 通讯作者: Benowitz, J.

Why is Denali (6,194 m) so big? Caught inside the tectonic wake of a migrating restraining bend

为什么麦金利峰（6,194 米）这么大？

• DOI: 10.1111/ter.12571
• 发表时间: 2021-11-15
• 期刊: Terra Nova
• 影响因子: 2.4
• 作者: Jeff A. Benowitz;M. Cooke;Patrick Terhune;S. Herreid;Sean P. Bemis;K. Toeneboehn;T. Waldien;P. O’Sullivan
• 通讯作者: P. O’Sullivan