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. ***
