Polar Seminar: Jeff Severinghaus - "The Rapid Access Ice Drill (RAID): Getting to bed in 2 days instead of 5 years"

05/18/2016 - 2:00pm
Revelle 4301
Event Description: 
Wednesday, May 18, 2:00PM
Location: Revelle 4301

Jeff Severinghaus
Professor, Scripps Institution of Oceanography, La Jolla, CA

The Rapid Access Ice Drill (RAID): Getting to bed in 2 days instead of 5 years
Ice cores have traditionally taken 5 years to complete, at a cost of upwards of $50M.
The reason for the slow pace is that cores are extracted a meter or two at a time,
along with the ice chips produced by drilling, in a version of the old “bucket full of
dirt” mining technique (chips are brought to the surface, along with the ice core
section, in a container and dumped out at the surface, which takes several hours).
As a consequence of this high cost in time and money, our knowledge of subglacial
conditions remains woefully inadequate.  Heat flow, bedrock geology, subglacial
till properties, lubrication mechanisms for ice flow, and many more topics, all remain
virtually unknown in this vast continent.  I will describe a new tool that has recently
been constructed, that drills to the bed in two days instead of five years, without
taking core but instead using a continuously circulating fluid system to carry the
chips to the surface, where they are screened out of the fluid so that the fluid may
be recycled and re-injected into the borehole.  Innovations such as borehole laser logging
of dust stratigraphy allows dating of the ice without taking ice cores, in just a few
hours, immediately after drilling.  Follow-up borehole temperature logging a year
later can establish heat flow with great precision, and borehole deformation studies
over the next 5 years can reveal the strain history.  Ice fabrics can now be remotely
sensed by borehole tools, and seismic experiments with borehole seismometers
can reveal new information.  We plan to drill 5 or 6 holes per season, from a sled-
mounted mobile platform that does not involve any camp that must be set up and
taken down (traverse mode).  Our first full-scale field test is at Minna Bluff near
McMurdo in December 2016.
For more information on this event, contact: 
Matthew Siegfried
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