J-9 Drill Hole Temperatures

The Ross Ice Shelf Project (RISP) began in 1973, and lasted six field seasons. One of the primary goals for RISP was to drill a hole through the Ross Ice Shelf in order to study the ice, the ocean, and the ocean floor beneath the ice shelf. In late November 1974, during the second field season, the camp at J-9 (82.375S, 168.626W) was established, and this site was chosen for future deep core drilling.

Drilling at J-9 began on November 27, 1974 and a depth of 100 meters was reached on November 30. The U.S. Army Cold Regions Research and Engineering Laboratory's (CRREL) shallow drill was used to drill the first ice core at J-9. Although a continuous ice core was unable to be retrieved, a temperature profile was obtained at J-9 during the 1974-1975 field season.

During the 1976-1977 field season the proposed drilling was to consist of four holes: the water well hole, the Bern hole, the core hole, and the access hole. Drilling of the Bern hole occured between November 5-20. A core of 103 meters was drilled before technical problems with the wireline core drill caused the crew to terminate core recovery attempts. The open hole (no core being retrieved) was drilled from 103 to 147 meters with the wireline drill. After switching to the CRREL thermal drill the Bern hole was advanced to a depth of 152 meters, and then became stuck. The drill was not recovered and it was decided that attempting to drill the core hole would be postponed until next field season. Before drilling of the access hole could start a hole 60 meters deep was made to pump sea water out of the access hole. Drilling of the access hole began on November 26. On December 13, 1976 the wireline rotary drill got stuck at 330.3 meters, and after failed recovery attempts, it was decided to leave the drill in place until next season. Temperature measurements were taken at the bottom of the hole as it was being drilled.

The Browning flame-jet drill was used during the 1977-1978 RISP season. Two access holes were made, the first hole was frozen before any scientific measurements could be made. The second hole successfully reached the base of the ice shelf at 420 meters on December 14. The hole had to be redrilled every 3 - 4 days due to refreezing, and was used until January 2.

During the final RISP season in 1978-1979 one major project achievement was the acquisition of ice core through the lower portion of the ice shelf by Dr. Igor A. Zotikov of the Institute of Geography in Moscow. A lightweight electrothermal drill was used, and rather than removing the melt water from the hole, antifreeze was added. The theory behind this was that the freezing point of this mixture would be near the temperature of the ice at each depth in order to maintian equilibrium without freezing the fluid in the hole. With this drill an ice core the entire thickness of the ice shelf (416 meters) was obtained and sub-shelf temperature measurements up to 230 meters below the bottom of the ice shelf were taken.


View Ice Temperature Profile for 1974.
View Table of data for 1974.


View Ice Temperature Profile for 1977.
View Table of data for 1977.


View sub-shelf Temperature Profile for 1978.
View Table of data for 1978.