Jökull - 01.12.2007, Síða 83

A hot water drill with built-in sterilization
Engelhardt, H., W.D. Harrison and B. Kamb 1978. Basal sliding
and conditions at the glacier bed as revealed by bore-hole
photography. J. Glaciology 20(84), 469–508.
Fard, A.M. 2002. Subglacial lakes: A planetary perspective.
Global and Planetary Change, Special Issue 35, 169–299.
Gaidos, E., B. Lanoil, Th. Thorsteinsson, A. Graham, M. Skid-
more, S-K. Han, T. Rust and B. Popp 2004. A viable micro-
bial community in a subglacial volcanic crater lake, Iceland.
Astrobiology 4(3), 327–244.
Hubbard, B. and N. Glasser 2005. Field Techniques in Glaciology
and Glacial Geomorphology. John Wiley & Sons, 400 pp.
Iken, A., K. Echelmeyer and W.D. Harrison 1989. A light-weight
hot water drill for large depth: Experiences with drilling
on Jakobshavn glacier, Greenland. In: Ice Core Drilling.
Proceedings of the Third International Conference on Ice
Drilling Technology, LGGE, Grenoble, France, 123–136.
Jonsson, J. 2006. NASA Jet Propulsion Laboratory Hydrothermal
Vent Bio-sampler. MSc. Thesis, Luleå University of Technol-
ogy, CIV 178, 74 pp.
Lane, A.L., P.G. Conrad, A. Behar, F. Carsey and L. French 2005.
A concept for an extremely sensitive in-situ instrument for
detecting biosignatures in deep ice and deep ocean environ-
ments. JPL Poster No. 05-145, Jet Propulsion Laboratory,
Pasadena, USA.
Pohjola, V. 1993. TV-video observations of bed and basal sliding
on Storglaciären, Sweden. J. Glaciology 39(131), 111–118.
Priscu, J. and B. Christner 2004. Earth’s icy biosphere. In: Alan
T. Bull (ed.). Microbial Diversity and Bioprospecting. ASM
Press, Washington DC., 130–145.
Siegert, M.A., J.C. Ellis-Evans, M. Tranter, C. Mayer, J.-R. Petit,
A. Salamatin and J.C. Priscu 2001. Physical, chemical and
biological processes in Lake Vostok and other Antarctic sub-
glacial lakes. Nature 414, 603–609.
Siegert, M.J., S. Carter, I. Tabacco, S. Popov and D. Blanken-
ship 2005. A revised inventory of Antarctic subglacial lakes.
Antarctic Science 17 (3), 453–460.
Taylor, P.L. 1984. A hot water drill for temperate ice. CRREL Spe-
cial Report 84-34, 105–117.
APPENDIX
To calculate the curves in Figures 4 and 5, we use for-
mulas (10) and (11) derived below. The following pa-
rameters are used in the calculations, see also Figure
6 for explanations.
Figure 6. Schematic drawing of the borehole, hose
and drill tip, indicating some of the parameters used
in the calculations. – Skýringarmynd er sýnir nokkra
hluta borsins sem notaðir eru í reikningum í viðauka.
T0 = initial temperature of drilling water in the hose
at surface
T = temperature of drilling water at the drill tip
Tf = pressure melting point of ice, assumed to be =
0!C over the pressure range considered
t = time (s)
mw/t = mass flow rate through the drill tip
mice/t = rate of ice melting at the bottom of the bore-
hole
lice = latent heat of fusion of ice = 334 kJkg"1
cpw = heat capacity of water at constant pressure =
4190 Jkg"1K"1
!ice = density of the ice = 900 kgm"3 (appropriate
value for bubbly, temperate ice)
Vice = volume of borehole drilled in time t
S = mean cross sectional area of borehole drilled in
time t
JÖKULL No. 57 81