Collaborative Research: Neotectonics and Structural Development of the Northern Walker Lane

合作研究：沃克巷北部的新构造学和构造发展

• 批准号: 1419724
• 负责人: Steven Wesnousky
• 金额: $ 45.56万
• 依托单位: Board of Regents, NSHE, obo University of Nevada, Reno
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1419724&HistoricalAwards=false
• 关键词: Collaborative; Research; Neotectonics; Structural; Development

The Walker Lane is a major element of the North American-Pacific plate boundary. This northwest trending zone of discontinuous active faults and disrupted topography that sits between the Sierra Nevada on the west and the north-northeast trending faults and ranges of the Great Basin to the east is associated with a well-defined zone of northwest-directed right-lateral shear based on GPS data. The Walker Lane has been suggested to mark the future site of the primary plate boundary thus research on the zone is fundamental to gaining an understanding of how a transform fault initiates and eventually becomes organized into a through-going plate boundary. This project focuses on a portion of northern Walker Lane in western Nevada where geologic evidence of this right-lateral shear is not evident and there is a discrepancy between geologic and GPS measurements of slip rate. LiDAR, geochronologic, and paleomagnetic data collected in this study are used to resolve this mismatch, detect unrecognized faults, and test if rotation of crustal blocks accommodates shear zone motion. The societal and scientific impact of the research will be enhanced by inclusion of both high school and undergraduate science students in the proposed research. The results will aid in assessment of seismic hazards in the Reno-Carson City corridor.This project focuses on the portion of the Walker Lane in Nevada that encompasses the Lake Tahoe, Carson, Smith, Mason, Antelope, Bridgeport and Walker Lake basins and Carson and Wabuska structural lineaments. Here, geodetic data indicate ongoing northwest directed right-lateral shear strain is accumulating at about 5 to 6 mm/year and cumulative shear displacement of 20-30 km has enigmatically resulted in the development of a set of roughly en echelon normal fault-bounded basins in the absence of any major northwest-directed strike-slip faults. This project will collect and analyze LiDAR for evidence of strike-slip along the major structures of the region, apply cosmogenic, optically stimulated luminescence, and radiocarbon dating to identified offset surfaces to better quantify the rate at which faults are slipping, and utilize gravity and paleomagnetism to clarify the long-term structural development of the basins. The project will test the hypothesis that the displacement field across the region is taken up by a combination of vertical-axis rotations, southeastward translation of crustal blocks approximately parallel to the Walker Lane, and opening of the en-echelon set of basins. The goals of the research are to: (1) locally clarify whether or not the mismatch in geodetic rates is real, (2) assess whether or not the blocks bounding the basins record rotation and, if so, related to observed basin asymmetry, (3) compare the collected observations in the framework of prior hypotheses concerning the structural development of this portion of the Walker Lane, and (4) and integrate the mode of deformation observed here to elsewhere in the Walker Lane and the San Andreas fault system with an aim toward understanding the processes associated with the structural initiation of a continental strike-slip fault system.

Walker Lane是北美太平洋板块边界的主要元素。西北趋势是不连续的主动断层和破坏的地形，位于西部塞拉山脉的内华达山脉与东北的偏向趋势断层和东方大盆地的范围与基于GPS数据的Northwest指导的右侧右侧剪切型与良好定义的右侧右侧剪切范围有关。建议沃克巷（Walker Lane）标记主要板界边界的未来位点，因此该区域的研究是了解转换断层如何启动并最终被组织到贯穿板块边界的基础。该项目的重点是内华达州西部北部沃克巷的一部分，那里的地质证据不明显，并且地质速率和GPS的测量值之间存在差异。本研究收集的LIDAR，测量学和古磁数据用于解决此不匹配，检测未识别的断层，并测试地壳块的旋转是否适合剪切区运动。这项研究的社会和科学影响将通过将高中和本科科学专业的学生纳入拟议的研究中来增强。结果将有助于评估雷诺 - 卡森城走廊中的地震危害。该项目重点介绍了内华达州沃克巷的一部分，其中包括托恩塔霍湖，卡森，史密斯，梅森，梅森，安芒，布里奇波特，布里奇波特和沃克湖盆地和卡森和卡森和瓦布斯卡的结构线。在这里，大地数据表明，西北持续的右侧剪切应变的累积约为5至6毫米/年，累积剪切位移为20-30 km，导致在缺乏任何重大的Northwest Northwest Disecred Disecred Disecred Disecred降低的情况下，发展了一组粗大的Echelon正常断层盆地。该项目将收集和分析LIDAR，以证明沿该地区的主要结构的滑移证据，应用宇宙生成，光学刺激的发光，并将放射性碳追溯到确定的偏移表面，以更好地量化故障的速率，并利用重力和古磁性，以阐明基础的长期结构发展。该项目将检验以下假设：跨区域的位移场是通过垂直轴旋转，与沃克巷平行的地壳块的东南转换以及盆地隔离集合的开口所占据的。该研究的目标是：（1）局部阐明地球速率的不匹配是真实的，（2）评估是否有界限盆地记录旋转的障碍物，以及与观察到的盆地不对称性有关的障碍，（3）比较了所收集的观察结果，比较了先前的假设框架的框架中的结构性开发模式，并建立了（4个步行者）的居住式（4 ane Lane and and of）（4到达Walker Lane和San Andreas断层系统中的其他地方，目的是了解与大陆滑道断层系统的结构启动相关的过程。