Collaborative Research: Probing the Thermal Evolution of the San Andreas Fault at Parkfield; Thermochronology in the San Andreas Fault Observatory at Depth (SAFOD)

从4公里深的圣安德烈亚斯断层带观测站（SAFOD）钻孔的岩石样品的分析提供了一个很好的机会，探讨断层力学的基本问题，有关断层的摩擦强度，同时扩大我们的知识，在帕克菲尔德，加州，地区的区域隆起历史。SAFOD将在最后与活跃的圣安德烈亚斯断层带相交之前，通过Salinian区块和圣安德烈亚斯断层系统至少一个废弃段附近提供样本。在先前对2002年采集的先导孔样品进行分析的基础上，使用低温热年代测定法（特别是磷灰石和锆石裂变径迹测年法、磷灰石和锆石晶体的（U-Th）/He测年法以及钾长石颗粒的39 Ar-40 Ar测年法）分析了深部Salinian样品以及废弃和活动断层段附近的样品。热年代学和补充建模研究的特点，长期的热演化的区域和探测故障本身的局部热扰动的证据。约束摩擦加热计时法提出了一个独立的方法，可以帮助建立摩擦性能的圣安德烈亚斯断层。

Analysis of rock samples from the 4-km-deep San Andreas Fault zone Observatory at Depth (SAFOD) drillhole provides an excellent opportunity to explore a fundamental question in fault mechanics regarding the frictional strength of faults, while simulataneously extending our knowledge of the regional uplift history in the Parkfield, California, area. SAFOD will provide samples through the Salinian block and from near at least one abandoned segment of the San Andreas fault system before finally intersecting the active San Andreas fault strand(s). Building on previous analysis of Pilot Hole samples collected in 2002, deep Salinian samples, as well as samples adjacent to the abandoned and active fault segments are analyzed using low temperature thermochronometry (specifically apatite and zircon fission-track dating, (U-Th)/He dating of apatite and zircon crystals, and 39Ar-40Ar dating of K-feldspar grains). The thermochronometry and complementary modeling studies characterize the long-term thermal evolution of the region and probe the faults themselves for evidence of localized thermal perturbations. Constraining frictional heating using thermochronometry presents an independent approach that can help establish the frictional properties of the San Andreas fault.