Vertical-strain measurements in firn at Siple Dome, Antarctica

• Main Authors: Robert L. Hawley, Edwin D. Waddington, Greggw Lamorey
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2005
• Subjects: Siple; Siple Dome; Antarc*; Antarctica
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.548.1480; http://earthweb.ess.washington.edu/~bo/papers/vstrain/hawley_et_al2004.pdf

ABSTRACT. We measured vertical strain in the firn at Siple Dome, Antarctica, using two systems, both of which measure relative displacements over time of metal markers placed in an air-filled borehole. One system uses a metal-detecting tuned coil, and the other uses a video camera to locate themarkers.We compare themerits of the two systems. We combine steady-state calculations and a measured density profile to estimate the true vertical-velocity profile.This allows us to calculate a depth^age scale for the firn at Siple Dome. Our steady-state depth^age scale has ages 10^15 % younger at any given depth when compared to depth^age scales derived by layer counting in a core 40m away. The age of a visible ash layer at 97m in the core is 66530 years, in agreement with a similar analysis conducted atTaylor Dome, Antarctica, where the same ash is also seen, providing an additional dated tie point between the two cores.