Collaborative Research: Low Temperature Thermochronology in the San Andreas Fault Observatory at Depth (SAFOD) Pilot Hole

0207388博格曼 圣安德烈亚斯断层带深度观测台（SAFOD）试验孔将提供一个极好的机会，通过使用两种互补的热年代学方法研究不同深度的岩心样品，探索断层滑动与地壳热演化之间的关系。 位于加州帕克菲尔德的先导孔距离圣安德烈亚斯断层不到两公里，深度将达到2.1公里。 钻孔将在不到1 km的深度处与Salinian花岗岩岩石相交，并且类似的花岗岩岩石在导向孔的几公里范围内露出地表。 主要调查人员将分析100 - 200 m深度间隔的钻孔岩屑和地表露头的样本。 他们将使用磷灰石裂变径迹和U/Th-He热年代计确定样品的热历史。这项研究将通过对垂直剖面样品使用多个热年代学系统来探索隆起、侵蚀和热流之间复杂的相互作用。 这些数据将使PI能够将隆升的影响与地热梯度的变化分开，例如由圣安德烈亚斯断层沿着产生的长期摩擦热造成的影响。 由于帕克菲尔德的隆升历史在一定程度上受到圣安德烈亚斯断层沿着滑动的控制，他们的工作也将提供有关断层运动学的信息。

0207388Burgmann The San Andreas Fault zone Observatory at Depth (SAFOD) Pilot Hole will provide an excellent opportunity for exploring the relationship between fault slip and the thermal evolution of the crust by studying core samples from varying depths using two complementary thermochronologic methods. The Pilot Hole, located in Parkfield, CA less than two kilometers from the San Andreas fault will reach a depth of 2.1 km. The borehole will intersect Salinian granite rocks at a depth of less than 1 km and similar granitic rocks outcrop at the surface within a few kilometers of the Pilot Hole. The Principal Investigators will analyze samples from borehole cuttings at depth intervals of 100 - 200 m and from the surface outcrops. They will determine the thermal history of the samples using apatite fission track and U/Th-He thermochronometers.This study will explore the complex interplay between uplift, erosion, and heat flow by using multiple thermochronologic systems on samples from a vertical profile. These data will allow the PIs to separate the effects of uplift from changes in the geothermal gradient, such as those resulting from the long-term frictional heat generated along the San Andreas fault. Because the uplift history at Parkfield is controlled, in part, by slip along the San Andreas fault, their work will also provide information about the kinematics of the fault.***