Results of Optical Dust Logger Operated in Siple Dome Borehole

Buford Price

FY01 season at Siple Dome

  1. Invention and operation of an optical dust logger: R. Bay, P. B. Price, G. D. Clow, A. J. Gow (2001). Climate logging with a new rapid optical technique at Siple Dome, GRL 28, 4635-4638.

  2. Logger detected LGM, a 65 kyr dust peak corresponding to dust peaks seen at Vostok Station and Dome Fuji, ~30 volcanic ash bands, a signal due to a 103-yr hiatus in accumulation at ~675 m, and other features.

  3. Collaboration with G. Zielinski and N. Dunbar on provenance and Ar-Ar age of deepest volcanic ash layer (950 m) at Siple Dome. No results yet.

FY02 season at Siple Dome

  1. Installed new electronics and horizontally beamed light sources in dust logger.

  2. Dust logger detected the ~30 volcanic ash bands + another ~10.

  3. Invented and operated a microbe logger; detected return signals in seven wavelength bands.

  4. The two loggers detected a strong 103-yr hiatus in accumulation at a depth of 900 m; an abrupt change in accumulation at 722 m; possible weak changes at a number of depths including 432 and 802 m; and a strong signal at ~995 m probably associated with silt and bedrock.

  5. Possible detection of annual layers in data at depths from ~90 m to ~600 m. Large variation in accumulation rates. Search for long-period modulation in progress.

Plans for modifications of dust logger and microbe logger

  1. To improve resolution of annual dust bands, use a horizontally directed laser.

  2. Redesign path of returned light to eliminate background of scattered light.