Vertical-strain measurements in firn at Siple Dome, Antarctica

Authors: Hawley, Robert L.; Waddington, Edwin D.; Lamorey, Gregg W.; Taylor, Kendrick C.

Source: Journal of Glaciology, Volume 50, Number 170, June 2004 , pp. 447-452(6)

Publisher: International Glaciological Society

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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 the markers. We compare the merits 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 40 m away. The age of a visible ash layer at 97 m in the core is 665 ± 30 years, in agreement with a similar analysis conducted at Taylor Dome, Antarctica, where the same ash is also seen, providing an additional dated tie point between the two cores.

Document Type: Research article

DOI: 10.3189/172756504781829972

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