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2007 – 2008 US ITASE Field Report

Page 4

Science

US ITASE Phase Two traveled from Taylor Dome to South Pole (Fig. 4).  During the 2007-2008 season US ITASE traveled 1200 km from the 2006-2007 winter-over site  (06-4) to South Pole. For details of the traverse route coordinates see ITASEWaypointsScience.xls attached to this report.

US ITASE route map
Figure 4 US ITASE route in red and work sites (yellow triangles). Note also location of crevasses discovered on aerial reconnaissance. Original traverse route was changed slightly to avoid these crevasses. Click on figure for larger version.

Fig. 5 is a summary of science products resulting from this season. Details are provided in the following text.

science products summary
Figure 5 Science products as a function of traverse distance.

Crevasse radar: Conducted in parallel with all travel.

Shallow radar: Firn stratigraphy in the upper ~100 m of the ice sheet was imaged using a 200 MHz Ground Penetrating Radar (GPR) system.  The system operated continuously along the entire traverse route, and several local profiles were collected at each ice core site.

Deep radar: The 3 MHz (deep) radar collected data along all but 15 km of the traverse route, plus local profiles at each of the ice core sites for a total of more than 1300 km of data.  Ice thickness ranged from 1500 to 3100 m and internal stratigraphy was detected to depths up to 2750 m.  At least one subglacial lake was found along the traverse route just north of Titan Dome.

Ice coring: Ice coring was conducted using both the 2” Rongbuk and the 3” Eclipse drill. The Rongbuk drill was used for recovery of shallow cores (<25m) dedicated to studies described below under surface glaciology.  The Eclipse drill was used to recover cores up to 100m depth at four sites (Fig. 4). At all sites the cores represent at least 200 years and more probably several hundred to >1000 years of record at some sites.  Stratigraphy was conducted on all ice cores recovered this season.

Surface snow sampling: Surface snow sampling was conducted at 30 km intervals along the 2007–2008 traverse route and every 10k between site 07–4 and South Pole (Fig. 6). This sampling consists of IC/isotope and ICPMS sample collection at the surface, 0–5cm and 0–15m.  This data is part of a continent wide ITASE surface sampling scheme that has already demonstrated the spatial distribution of major ions and stable isotopes over Antarctica.

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