scholarly journals Thermal electric ice-core drills: history and new design options for intermediate-depth drilling

2014 ◽  
Vol 55 (68) ◽  
pp. 322-330 ◽  
Author(s):  
V. Zagorodnov ◽  
L.G. Thompson
Keyword(s):  
Low Power ◽  
Water Solution ◽  
Drilling Fluid ◽  
Ice Core ◽  
Polar Ice ◽  
Pure Ethanol ◽  
Intermediate Depth ◽  
Ice Caps ◽  
Drilling System ◽  
Design Options

AbstractIce coring of temperate and polythermal glaciers demonstrates some limitations of most electromechanical (EM) and thermal electric (TE) drills. Most TE drills are heavy, require a heavy power system, work slowly and cannot operate in boreholes going through the cold–temperate ice transition. Antifreeze thermal electric drills (ATED) are capable of operating in polar ice caps, polythermal and temperate glaciers, in boreholes filled with water and/or hydrophilic fluids. Performance of the ATED drill can be improved by using an open-top core barrel and low-power and narrow-kerf coring head. ATED-type drills can be modified for an open-top core barrel equipped with low-power coring head and include a new scheme for drilling-fluid circulation using two pumps. A small metering pump releases pure ethanol above the top of the drill, and a second pump enables circulation of the borehole fluid, an ethanol–water solution (EWS), above the kerf. Use of a narrow-kerf coring head reduces power requirements and makes it possible to design a lightweight drilling system that includes the EM and TE drills for shallow and intermediate-depth drilling.

scholarly journals Intermediate-depth ice coring of high-altitude and polar glaciers with a lightweight drilling system

2005 ◽  
Vol 51 (174) ◽  
pp. 491-501 ◽  
Author(s):  
V. Zagorodnov ◽  
L.G. Thompson ◽  
P. Ginot ◽  
V. Mikhalenko
Keyword(s):  
High Altitude ◽  
Drilling Fluid ◽  
Ice Core ◽  
Ice Cores ◽  
Cutting Fluid ◽  
Intermediate Depth ◽  
Ice Cap ◽  
Dust Composition ◽  
Electric Drill ◽  
Drilling System

AbstractA total of 11 ice cores to a maximum depth of 460 m have been obtained over the past 3 years from high-altitude glaciers on the saddle of Mount Bona and Mount Churchill in Alaska (designated B–C), and on Quelccaya ice cap and Nevado Coropuna in Peru. Ice coring was conducted using an intermediate-depth drilling system. The system includes an electromechanical drill (EMD) and an ethanol thermal electric drill (ETED). The EMD permitted an average ice-core production rate (ICPR) of 7.0 m h−1 down to 150 m. An average ICPR of 2 m h−1 to 460 m depth was possible with the ETED. The quality of the B–C ice cores is better than that of cores previously drilled with an EMD and ETED system. A new cutter design, drilling with a lubricant/cutting fluid and a new anti-torque assembly were tested in the laboratory and in glacier boreholes. We examine the performance of the drills in cold and temperate ice and in clean and particle-laden ice. The influence of the ethanol drilling fluid on ice-core isotopic, ionic and dust composition is discussed.

scholarly journals RADIX: a minimal-resources rapid-access drilling system

2014 ◽  
Vol 55 (68) ◽  
pp. 34-38 ◽  
Author(s):  
J. Schwander ◽  
S. Marending ◽  
T.F. Stocker ◽  
H. Fischer
Keyword(s):  
Drilling Fluid ◽  
Ice Core ◽  
Ice Sheet ◽  
Minimum Size ◽  
Rapid Access ◽  
Drilling System ◽  
Low Costs ◽  
Drilling Site ◽  
Remote Sensing Methods

AbstractDetermining the expected age at a potential ice-core drilling site on a polar ice sheet generally depends on a combination of information from remote-sensing methods, estimates of current accumulation and modelling. This poses irreducible uncertainties in retrieving an undisturbed ice core of the desired age. Although recently perfected radar techniques will improve the picture of the ice sheet below future drilling sites, rapid prospective drillings could further increase the success of deep drilling projects. Here we design and explore a drilling system for a minimum-size rapid-access hole. The advantages of a small hole are the low demand for drilling fluid, low overall weight of the equipment, fast installing and de-installing and low costs. We show that, in theory, drilling of a 20 mm hole to a depth of 3000 m is possible in ∼4 days. First concepts have been realized and verified in the field. Both the drill cuttings and the hole itself can be used to characterize the properties of the ice sheet and its potential to provide a trustworthy palaeo-record. A candidate drilling site could be explored in ∼2 weeks, which would enable the characterization of several sites in one summer season.

scholarly journals The Influence On Atmospheric Composition of Volcanic Eruptions as Derived From Ice-Core Analysis

1985 ◽  
Vol 7 ◽  
pp. 125-129 ◽  
Author(s):  
C.U. Hammer
Keyword(s):  
Ice Core ◽  
Ice Sheets ◽  
Ice Cores ◽  
Volcanic Eruptions ◽  
Atmospheric Composition ◽  
Core Analysis ◽  
Polar Ice ◽  
Ice Caps ◽  
The Past ◽  
Polar Ice Sheets

Polar ice cores offer datable past snow deposits in the form of annual ice layers, which reflect the past atmospheric composition. Trace substances in the cores are related to the past mid-tropospheric impurity load, this being due to the vast extent of the polar ice sheets (or ice caps), their surface elevations and remoteness from most aerosol sources. Volcanic eruptions add to the rather low background impurity load via their eruptive products. This paper concentrates on the widespread influence on atmospheric impurity loads caused by the acid gas products from volcanic eruptions. In particular the following subjects are discussed: acid volcanic signals in ice cores, latitude of eruptions as derived by ice-core analysis, inter-hemispheric dating of the two polar ice sheets by equatorial eruptions, volcanic deposits in ice cores during the last glacial period and climatic implications.

scholarly journals The Influence On Atmospheric Composition of Volcanic Eruptions as Derived From Ice-Core Analysis

1985 ◽  
Vol 7 ◽  
pp. 125-129 ◽  
Author(s):  
C.U. Hammer
Keyword(s):  
Ice Core ◽  
Ice Sheets ◽  
Ice Cores ◽  
Volcanic Eruptions ◽  
Atmospheric Composition ◽  
Core Analysis ◽  
Polar Ice ◽  
Ice Caps ◽  
The Past ◽  
Polar Ice Sheets

Polar ice cores offer datable past snow deposits in the form of annual ice layers, which reflect the past atmospheric composition. Trace substances in the cores are related to the past mid-tropospheric impurity load, this being due to the vast extent of the polar ice sheets (or ice caps), their surface elevations and remoteness from most aerosol sources. Volcanic eruptions add to the rather low background impurity load via their eruptive products. This paper concentrates on the widespread influence on atmospheric impurity loads caused by the acid gas products from volcanic eruptions. In particular the following subjects are discussed: acid volcanic signals in ice cores, latitude of eruptions as derived by ice-core analysis, inter-hemispheric dating of the two polar ice sheets by equatorial eruptions, volcanic deposits in ice cores during the last glacial period and climatic implications.

scholarly journals Differentiating bubble-free layers from melt layers in ice cores using noble gases

2015 ◽  
Vol 61 (227) ◽  
pp. 585-594 ◽  
Author(s):  
Anais J. Orsi ◽  
Kenji Kawamura ◽  
John M. Fegyveresi ◽  
Melissa A. Headly ◽  
Richard B. Alley ◽  
...  
Keyword(s):  
Reliable Method ◽  
Gas Transport ◽  
Ice Core ◽  
Ice Cores ◽  
Gas Composition ◽  
Polar Ice ◽  
Clathrate Formation ◽  
Ice Caps ◽  
The Core ◽  
Visual Identification

AbstractMelt layers are clear indicators of extreme summer warmth on polar ice caps. The visual identification of refrozen meltwater as clear bubble-free layers cannot be used to study some past warm periods, because, in deeper ice, bubbles are lost to clathrate formation. We present here a reliable method to detect melt events, based on the analysis of Kr/Ar and Xe/Ar ratios in ice cores, and apply it to the detection of melt in clathrate ice from the Eemian at NEEM, Greenland. Additionally, melt layers in ice cores can compromise the integrity of the gas record by dissolving soluble gases, or by altering gas transport in the firn, which affects the gas chronology. We find that the easily visible 1 mm thick bubble-free layers in the WAIS Divide ice core do not contain sufficient melt to alter the gas composition in the core, and do not cause artifacts or discontinuities in the gas chronology. The presence of these layers during winter, and the absence of anomalies in soluble gases, suggests that these layers can be formed by processes other than refreezing of meltwater. Consequently, the absence of bubbles in thin crusts is not in itself proof of a melt event.

scholarly journals A new intermediate-depth ice-core drilling system

2014 ◽  
Vol 55 (68) ◽  
pp. 271-284 ◽  
Author(s):  
Simon G. Sheldon ◽  
Trevor J. Popp ◽  
Steffen B. Hansen ◽  
Thomas M. Hedegaard ◽  
Carsten Mortensen
Keyword(s):  
Future Development ◽  
Ice Core ◽  
Ice Cores ◽  
Snow Surface ◽  
High Quality ◽  
International Partnerships ◽  
Intermediate Depth ◽  
Ice Cap ◽  
Drilling System ◽  
Set Up

AbstractSeveral recent projects associated with the IPICS (International Partnerships in Ice Core Sciences) 2k array have demanded the recovery of ice core to depths in excess of several hundred metres (e.g. Flade Isblink, Greenland (2006), Aurora Basin, Antarctica (2008/09), NEEM, Greenland (2011), Aurora Basin North (2013/14) and Renland ice cap, Greenland (2015)). These projects require that the overall system weight is low, that the ability to set up and operate are within the limitations of a small-camp environment and that the overall logistical and transportation costs are kept to a minimum. Using these criteria, a new drilling system capable of drilling >400m depth was seen as a useful future development. Here we report on a new intermediate-depth drilling system designed to recover high-quality 98 mm diameter ice cores from close to surface down to depths of 1000 m by two or more operators in a small deep-field camp environment. The total weight of the system on the snow surface is ∼490 kg, of which the intermediate-depth winch is the single heaviest component at 305 kg with 1000 m of cable.

scholarly journals Nonequilibrium air clathrate hydrates in Antarctic ice: a paleopiezomdter for polar ice caps

1993 ◽  
Vol 90 (23) ◽  
pp. 11416-11418 ◽  
Author(s):  
H Craig ◽  
H Shoji ◽  
C C Langway
Keyword(s):  
Phase Boundary ◽  
Numerical Models ◽  
Equilibrium Phase ◽  
Vertical Displacement ◽  
Polar Ice ◽  
Ice Flow ◽  
Air Bubble ◽  
Ice Caps ◽  
General Parameter ◽  
Approximate Composition

"Craigite," the mixed-air clathrate hydrate found in polar ice caps below the depth of air-bubble stability, is a clathrate mixed crystal of approximate composition (N2O2).6H2O. Recent observations on the Byrd Station Antarctic core show that the air hydrate is present at a depth of 727 m, well above the predicted depth for the onset of hydrate stability. We propose that the air hydrate occurs some 100 m above the equilibrium phase boundary at Byrd Station because of "piezometry"--i.e., that the anomalous depth of hydrate occurrence is a relic of a previous greater equilibrium depth along the flow trajectory, followed by vertical advection of ice through the local phase-boundary depth. Flowline trajectories in the ice based on numerical models show that the required vertical displacement does indeed occur just upstream of Byrd Station. Air-hydrate piezometry can thus be used as a general parameter to study the details of ice flow in polar ice caps and the metastable persistence of the clathrate phase in regions of upwelling blue ice.

scholarly journals Stokes’s Theorem, Data, and the Polar Ice Caps

2018 ◽  
Vol 125 (9) ◽  
pp. 830-834
Author(s):  
Yuliy Baryshnikov ◽  
Robert Ghrist
Keyword(s):  
Polar Ice ◽  
Ice Caps

scholarly journals Concept and Testing of a Remotely Operated Vehicle-Mountable Inductive Electrothermal Polar Under-Ice Corer

2017 ◽  
Vol 51 (6) ◽  
pp. 33-43 ◽  
Author(s):  
Narayanaswamy Vedachalam ◽  
Arumugam Vadivelan ◽  
Arunachalam Umapathy ◽  
Munusamy Murugesan ◽  
Gopal Durai ◽  
...  
Keyword(s):  
Ice Core ◽  
Input Power ◽  
Design Development ◽  
Polar Ice ◽  
Remotely Operated Vehicle ◽  
Element Analysis ◽  
Ice Shelves ◽  
Core Samples ◽  
Inner Diameter ◽  
Aided Design

AbstractIce core samples from the polar ice shelves contain valuable paleo-climatic records and information for understanding the unique polar under-ice ecosystem. This paper describes the finite element analysis-aided design, development, and qualification of a 63-mm-inner diameter, 250-mm-long variable power underwater remotely operated vehicle-mountable inductive ice corer (IIC) for collecting ice core samples beneath the polar ice shelves. It is determined that, with the IIC operating with an input power of 1,000 W at 30 kHz, it is possible to have an ice penetration rate of 14 mm/min and obtain an ice core of 51 mm in diameter. The experimental results are found to comply with the numerical model with an accuracy of 95%.

Experimental Evaluation of Separation Methods for a Riser Dilution Approach to Dual Density Drilling

2009 ◽  
Author(s):  
John Shelton ◽  
John Rogers Smith ◽  
Anuj Gupta
Keyword(s):  
Emulsion Stability ◽  
Drilling Fluid ◽  
Feed Stream ◽  
Separation System ◽  
Qualitative Comparison ◽  
Deepwater Drilling ◽  
Drilling System ◽  
The Stability ◽  
Dual Gradient ◽  
Laboratory Centrifuge

A dual gradient, deepwater drilling system based on dilution of riser mud requires economically separating the riser mud into a low density dilution fluid and a higher density drilling fluid. This study investigated the practicality of accomplishing this separation using hydrocyclones and centrifuges and examined the possible benefits and efficiency of each. The separation experiments were conducted using a laboratory centrifuge and 2 inch hydrocyclones. The laboratory centrifuge was able to separate the riser mud into near ideal densities for dilution and drilling fluid. However, the dense slurry retained in the centrifuge had lower emulsion stability than the feed stream. The hydrocyclones achieved much less contrast in density between the low and high density discharges, but consistently resulted in a beneficial increase in the stability of the mud emulsion in all of the flow streams and had more desirable rheological properties. A qualitative comparison indicates that the hydrocyclone separation system may offer a feasible and desirable alternative to centrifuge separation system.

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