Timing of Intracontinental Deformation across the Eastern Mono Basin, California and Nevada

加利福尼亚州和内华达州东部莫诺盆地的陆内变形时间

• 批准号: 1321763
• 负责人: Michael Petronis
• 金额: $ 15.44万
• 依托单位: New Mexico Highlands University
• 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: 2013-07-15 至 2017-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1321763&HistoricalAwards=false
• 关键词: Timing; Intracontinental; Deformation; across; Eastern

Modern deformation between the North American and Pacific plates is distributed across a wide zone of western North America from the San Andreas fault eastward into the western Basin and Range Province. The eastern Mojave Desert and the region between the Sierra Nevada and Great Basin form a zone of distributed deformation that accommodates about 25 percent of the relative motion between the Pacific and North American plates. Deformation to the south is localized within the Eastern California Shear Zone and to the north in the Walker Lane Belt, which today is characterized by northwest-trending faults with associated earthquake focal mechanisms and GPS velocities that are indicative of transtensional deformation. This project tests the hypothesis that deformation associated with the transtensional system during the early to mid-Miocene was located east of the Sierra Nevada front in the area of the Mono Basin prior to stepping east into the Mina Deflection in the late Miocene. To do so the research team is carrying out a detailed paleomagnetic study of the Oligocene to Pliocene mafic to intermediate lava flows, rhyolitic ignimbrites, sediments in the Mono Basin area (Huntoon Valley, Adobe Hills, Antelope Mountains, Cowtrack Mountains) to determine the spatial and temporal patterns of vertical axis rotation. Field structural studies coupled with 40Ar/39Ar geochronology of volcanic and intrusive rocks are used to constrain the fault geometry, kinematics, magnitude of fault slip, and the timing of deformation.The Eastern California Shear Zone and Walker Lane Belt, a zone that stretches from the Mojave Desert to northern California/northwestern Nevada, are important fault systems that accommodate a substantial portion of the motion of between the North American and Pacific plates, with most of the motion taken up by the San Andreas fault. However, the tectonic evolution of this complex fault zone remains poorly understood. This project aims to resolve an important part of the puzzle in that it would contribute to a better understanding of how deformation shifts through time. The project has a significant component of student involvement. Improving students' technological and basic science skill-sets will train and foster research endeavors for minority and underrepresented students.

北美和太平洋板块之间的现代变形分布在北美西部的广阔区域，从圣安德烈亚斯断层向东延伸到西部盆地和山脉省。莫哈韦沙漠东部以及内华达山脉和大盆地之间的区域形成了一个分布变形区，容纳了太平洋板块和北美板块之间约 25% 的相对运动。南部的变形位于东加州剪切带内，北部的变形位于沃克莱恩带内，该带如今的特点是西北走向的断层，以及相关的地震震源机制和表明张紧变形的 GPS 速度。该项目测试了这样的假设：中新世早期至中期与转张系统相关的变形位于内华达山脉前缘以东的莫诺盆地区域，然后向东进入中新世晚期的米纳偏转。为此，研究小组正在对莫诺盆地地区（Huntoon Valley、Adobe Hills、Antelope Mountains、Cowtrack Mountains）的渐新世至上新世镁铁质至中间熔岩流、流纹质熔结岩、沉积物进行详细的古地磁研究，以确定空间和垂直轴旋转的时间模式。现场结构研究与火山岩和侵入岩的 40Ar/39Ar 地质年代学相结合，用于约束断层几何形状、运动学、断层滑动幅度和变形时间。东加州剪切带和沃克巷带，该区域从从莫哈韦沙漠到加利福尼亚州北部/内华达州西北部，都是重要的断层系统，它们容纳了北美板块和太平洋板块之间的大部分运动，其中大部分运动由板块承担圣安地列斯断层。然而，人们对这个复杂断裂带的构造演化仍然知之甚少。该项目旨在解决这个难题的一个重要部分，因为它将有助于更好地理解变形如何随时间变化。该项目有学生参与的重要组成部分。提高学生的技术和基础科学技能将培训和促进少数族裔和代表性不足的学生的研究工作。