A new 122 mm electromechanical drill for deep ice-sheet coring (DISC): 5. Experience during Greenland field testing

Johnson, Jay A.; Mason, William P.; Shturmakov, Alexander J.; Haman, Scott T.; Sendelbach, Paul J.; Mortensen, Nicolai B.; Augustin, Laurent; Dahnert, Kristina R.

doi:10.3189/172756407786857730

Cited by 14 publications

(13 citation statements)

References 4 publications

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“…At the completion of each drill run, the DISC drill’s tower and sonde were tilted horizontally to allow for the removal of the core barrel and servicing of the sonde (Shturmakov and others, 2007). After the core barrel was disconnected from the rest of the sonde, it was lifted and rotated 180° using an 1814kg (2 ton) gantry crane fitted with a barrel-lifting and -rotating fixture (Johnson and others, 2007). The core barrel was then lowered onto a stainless-steel ‘Core Transfer Truss’ that abutted the wall common to the core-handling arch.…”

Section: Core Handling and Logging At Wais Dividementioning

confidence: 99%

Core handling and processing for the WAIS Divide ice-core project

Souney¹,

Twickler²,

Hargreaves

et al. 2014

Ann. Glaciol.

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ABSTRACT. On 1 December 2011 the West Antarctic Ice Sheet (WAIS) Divide ice-core project reached its final depth of 3405 m. The WAIS Divide ice core is not only the longest US ice core to date, but is also the highest-quality deep ice core, including ice from the brittle ice zone, that the US has ever recovered. The methods used at WAIS Divide to handle and log the drilled ice, the procedures used to safely retrograde the ice back to the US National Ice Core Laboratory (NICL) and the methods used to process and sample the ice at the NICL are described and discussed.

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Section: Core Handling and Logging At Wais Dividementioning

confidence: 99%

Core handling and processing for the WAIS Divide ice-core project

Souney¹,

Twickler²,

Hargreaves

et al. 2014

Ann. Glaciol.

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“…The ice sticks were obtained from the National Science Foundation National Ice Core Laboratory (Lakewood, Colorado) and were a by-product of the initial tests of the US Deep Ice Sheet Coring Drill performed in Greenland in 2006 (Johnson et al, 2007). The same drill was deployed in West Antarctica to obtain the WAIS Divide ice core, which we discuss in Sect.…”

Section: Greenland Test Icementioning

confidence: 99%

Improved methodologies for continuous-flow analysis of stable water isotopes in ice cores

et al. 2017

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Abstract. Water isotopes in ice cores are used as a climate proxy for local temperature and regional atmospheric circulation as well as evaporative conditions in moisture source regions. Traditional measurements of water isotopes have been achieved using magnetic sector isotope ratio mass spectrometry (IRMS). However, a number of recent studies have shown that laser absorption spectrometry (LAS) performs as well or better than IRMS. The new LAS technology has been combined with continuous-flow analysis (CFA) to improve data density and sample throughput in numerous prior ice coring projects. Here, we present a comparable semiautomated LAS-CFA system for measuring high-resolution water isotopes of ice cores. We outline new methods for partitioning both system precision and mixing length into liquid and vapor components -useful measures for defining and improving the overall performance of the system. Critically, these methods take into account the uncertainty of depth registration that is not present in IRMS nor fully accounted for in other CFA studies. These analyses are achieved using samples from a South Pole firn core, a Greenland ice core, and the West Antarctic Ice Sheet (WAIS) Divide ice core. The measurement system utilizes a 16-position carousel contained in a freezer to consecutively deliver ∼ 1 m × 1.3 cm 2 ice sticks to a temperature-controlled melt head, where the ice is converted to a continuous liquid stream and eventually vaporized using a concentric nebulizer for isotopic analysis. An integrated delivery system for water isotope standards is used for calibration to the Vienna Standard Mean Ocean Water (VSMOW) scale, and depth registration is achieved using a precise overhead laser distance device with an uncertainty of ±0.2 mm. As an added check on the system, we perform inter-lab LAS comparisons using WAIS Divide ice samples, a corroboratory step not taken in prior CFA studies. The overall results are important for substantiating data obtained from LAS-CFA systems, including optimizing liquid and vapor mixing lengths, determining melt rates for ice cores with different accumulation and thinning histories, and removing system-wide mixing effects that are convolved with the natural diffusional signal that results primarily from water molecule diffusion in the firn column.

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“…Successful operation of the DISC drill was enhanced and aided by several key auxiliary systems. Layout of the drill system was very similar to that used during the 2006 field test in Greenland (Johnson and others, 2007), with a few improvements made to increase efficiency of operations. A sliding window was implemented in the drill control room next to the operator’s desk and allowed for communication with personnel out on the drill floor as well as an improved view of the drill tower, cable and sonde as it entered the borehole.…”

Section: Auxiliary Systemsmentioning

confidence: 99%

Production drilling at WAIS Divide

Slawny¹,

Johnson²,

Mortensen³

et al. 2014

Ann. Glaciol.

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ABSTRACT. The deep ice-sheet coring (DISC) drill was used for production ice-core drilling at WAIS Divide in Antarctica for six field seasons between 2007 and 2013. Continuous ice-core samples were obtained between the snow surface and 3405 m depth. During the 2012/13 austral summer, the DISC drill's newly designed replicate ice-coring system was utilized to collect nearly 285 m of additional high-quality core samples at depths of high scientific interest. Annual progress graphs are described, as well as milestones achieved over the course of the project. Drilling operations, challenges encountered, drill fluid usage, drilling results, and the drill crew's experiences with the DISC drill and replicate coring system during production drilling are described and discussed in detail. Core-processing operations are described briefly, as well as the logistical undertaking of the DISC drill's deployment to Antarctica.

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A new 122 mm electromechanical drill for deep ice-sheet coring (DISC): 5. Experience during Greenland field testing

Cited by 14 publications

References 4 publications

Core handling and processing for the WAIS Divide ice-core project

Core handling and processing for the WAIS Divide ice-core project

Improved methodologies for continuous-flow analysis of stable water isotopes in ice cores

Production drilling at WAIS Divide

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