30 September 2019 to 3 October 2019
The Royal Danish Academy of Sciences and Letters
Europe/Copenhagen timezone

Rapid intermediate depth ice sampling with electromechanical coring drill.

3 Oct 2019, 09:20
20m
The Royal Danish Academy of Sciences and Letters

The Royal Danish Academy of Sciences and Letters

The Royal Danish Academy of Sciences and Letters H.C. Andersens Boulevard 35 DK-1553 Copenhagen V Denmark
Oral Session 6

Speaker

Dr Victor Zagorodnov (Cryosphere Research Solutions LLC, Columbus, OH, USA)

Description

High production rate ice coring systems allow for fast ice sampling in intermediate depths. Several ice coring operations in Greenland and Antarctica ice sheets and in high altitude glaciers demonstrate ability of the dry hole electromechanical (EM) ice coring drills rich depth of a few hundred meters in a short time. The highest average production drilling rate (aPDR) of 4.79 m/h in 310 m deep borehole (BH) was achieved in Guliya glacier (Tibet, 2015). Depending on drilling conditions decent and acceptable quality ice cores were obtained down to 140-180 m depth. In Guliya BH at least one 0.1-0.3 m long section of the ice core was obtained down to 310 m. The rest of 0.8-1.1 m long samples was presented by irregular shape ice chunks. In polar glaciers below 100-140 m samples mainly composed of 3-10 mm thick disks.
Modification of drilling protocol of the BPRC EM drill allows reduction of surface time for 40%. Then aPDR at 300 m depth will be close to 7 m/h while in 600 m deep BH the aPDR is about 6.5 m/h. Ice sampling with EM coring drill down to 1000 m possible with hoist system modifications, 20 h/day operation in ice temperatures below -40C. The major limitation of the dry hole drilling is rheological BH closure. Estimates shows that at -55C ice temperature depth of 600 m can be reached in 93 h without BH reaming. Sampling down to 1000 m will require 2-3 reaming (total about 8 h) and total 170 h operation.

Primary author

Dr Victor Zagorodnov (Cryosphere Research Solutions LLC, Columbus, OH, USA)

Co-authors

Lonnie G. Thompson (Ohio State University, Columbus OH, USA) Vladimir Mikhalenko (nstitute of Geography Russian Academy of Sciences, Moscow, Russia) Stanislav Kutuzov (Institute of Geography Russian Academy of Sciences, Moscow, Russia)

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