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

沃克巷是北美-太平洋板块边界的主要组成部分。这个位于西面内华达山脉和东面北东向断裂和大盆地山脉之间的不连续活动断裂和被破坏的地形的西北走向带，与基于GPS数据的明确的西北向右旋剪切带有关。沃克巷被建议用来标记主要板块边界的未来位置，因此对该带的研究对于了解转换断层如何开始并最终组织成贯通的板块边界是基本的。该项目集中在内华达州西部沃克巷北部的一部分，那里的地质证据不明显，这种右旋剪切的地质证据不明显，而且地质测量和GPS测量的滑动速率之间存在差异。在这项研究中收集的激光雷达、地质年代学和古地磁数据被用来解决这种不匹配问题，探测未识别的断层，并测试地壳块体的旋转是否适应剪切带运动。通过将高中和本科生纳入拟议的研究，这项研究的社会和科学影响将得到加强。研究结果将有助于评估雷诺-卡森市走廊的地震危险性。该项目的重点是内华达州沃克巷的一部分，包括太浩湖、卡森、史密斯、梅森、羚羊、布里奇波特和沃克湖盆地以及卡森和瓦布斯卡构造线条。在这里，大地测量数据表明，持续的北西向右旋剪切应变以每年约5-6 mm的速度累积，20-30公里的累积剪切位移神秘地导致了一组在没有任何主要的北西向走滑断裂的情况下发育的大致梯形的正断层盆地。该项目将收集和分析LiDAR以寻找沿该地区主要构造的走滑证据，将宇宙成因、光激发发光和放射性碳测年应用于已识别的偏移面，以更好地量化断层滑动的速度，并利用重力和古地磁来阐明盆地的长期构造发展。该项目将检验这样一种假设，即整个区域的位移场是由垂直轴旋转、大致平行于Walker Lane的地壳块体向东南平移以及梯形盆地组的打开共同占据的。这项研究的目的是：(1)局部澄清大地速率失配是否真实存在，(2)评估环绕盆地的地块是否记录了旋转，如果是，是否与观测到的盆地不对称有关，(3)在先前关于Walker Lane这一部分结构发展的假设框架内比较收集到的观测数据，以及(4)将此处观测到的形变模式与Walker Lane和San Andreas断裂系统中的其他地方进行整合，以期了解与大陆走滑断裂系统的构造启动相关的过程。

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.