Skip to main content Accessibility help
×
Home

Sub-sea permafrost regime at Prudhoe Bay, Alaska, U.S.A

  • T. E. Osterkamp (a1) and W. D. Harrison (a1)

Abstract

A sub-sea permafrost drilling program was conducted near Prudhoe Bay, Alaska. Sub-sea permafrost was found at all offshore drill sites and was characterized as being ice bonded or unbonded. The unbonded sub-sea permafrost occurred in a thin layer at the sea bed; the near-shore thickness of this layer appears to be controlled by the bathymetry. The mean annual sea-bed temperatures were about —3.4°C at 203 m offshore, — 1.1°C at 481 m offshore and —0.7°C at 3370 m offshore. The thermal diffusivity was about 21 m2 a-1 for unbonded sandy gravel with silt. The sub-sea permafrost soils were sandy gravel with some silt overlain by a thin layer of silty sand which increased in thickness from a few meters near shore to about 14 m at 3370 m offshore. A few small ice lenses were found in a hole 195 m offshore but no massive ice was observed. Pore-water salt concentrations at the sea bed were 3-4 times that of normal sea-water where ice was frozen to the sea bed and 1–2 times that of normal sea-water otherwise. Preliminary laboratory experiments showed that the saturated hydraulic conductivity of the unbonded sub-sea permafrost was about 10–6–10–7 m s–1. The permeability of the subterranean permafrost was zero.

Résumé

Régilm de permafrost sous-marin á Prudhoe Bay, Alaska, U.S.A. Un programme de forage dans le permafrost sous-marin á été exécuté près de Prudhoe Bay en Alaska. Des permafrosts sous-marin ont été trouvé á tous les sites de forages au large et on les caractérisait comme étant Iiaisonnés ou non liaisonnés par de la glace. Le permafrost sous-marin non liaisonné se produisait en une mince couche au niveau du fond de la mer; l'épaisseur, près des côtes, de ce niveau semble contrôlé par la bathymétrie. Les températures moy ennes annuelles du fond de la mer étaient d'environ — 3,4°C à 203 m du rivage, —1,1 °C à 481 m du rivage et —0,7°C à 370 m vers le large. La diffusivité thermique était d'environ 21 m2 a–1 pour un gravier sablonneux non liaisonné avec du limon. Les sols de permafrost sous-marin étaient en gravier sablonneux avec un peu de limon surmonté par un mince niveau de sable limoneux qui croît en épaisseur depuis quelques mètres près de la côte jusqu'à environ 14 m à 3 370 m au large. Quelques petites lentilles de glace ont été trouvées dans un forage de 195 m de la côte, mais on n'a pas trouvé de glace en quantité massive sous la mer. Les concentrations en sel des pores dans le fond de la mer étaient 3 ou 4 fois plus élevées que celles de l’eau de mer normale où la glace était fixée sur le fond de la mer et une à deux fois celle de l'eau de mer normale ailleurs. Des expériences préliminaires de laboratoire ont montré que la conductivité hydraulique saturée du permafrost sous-marin non liaisonné était d'environ 10–6 à 10–7m s–1. La perméabilité du permafrost souterrain était nulle.

Zusammenfassung

Hallshalt des Permafrostes am Meeresboden der Prudhoe Bay, Alaska, U.S.A. Nahe der Prudhoe Bay in Alaska wurde ein Bohrprogramm für unterseeisehe Permafrost durchgeführt. Untersceischer Permafrost wurde an alien Bohrstellen vor der Küste gefunden; er liess sich als gefunden order nicht gebunden an Eis charakterisieren. Der ungebundene Permafrost unter wasser trat als dünne Schicht am Meeresboden auf; die Dicke dieser Schicht nahe der Küste scheint von der Tiefenlage abzuhängen. Die mittleren Jahrestemperaturen des Meeresbodens betrugen etwa — 3,4°C bei 203 m Küstenabstand, — 1,1°C bei 481 m Küstenabstand und –0,7°C bei 3 370 m Küstenabstand. Die thermische Diffusion war für ungebun-denen sandigcn Kies mit Schlamm etwa 21 m2 pro Jahr. Die Permafrostböden unter Wasscr bestanden aus sandigem Kies mit einigem Schlamm, Überlagert von einer dünnen Schicht schlammigen Sandes, deren Dieke von wenigen Metern in Küstennahe auf etwa 14 m in 3 370 m Küstenabstand zunahm. In einem Loch bei 195 m Küstenabstand wurden einige kleine Eislinsen gefunden, doch fand sich weiter draussen kein zusammcnhängendes Eis. Die Salzkonzentration im Porenwasser am Meeresgrund war 3- bis 4-mal grösser als sonst in normalem Meerwasser. Vorläufige Laborversuche ergaben, dass die gesättigte hydraulische Leitfähigkeit des ungebundenen unterseeischen Permafrostes ungefähr 10–6 bis 10–7ms–1 beträgt. Die Durchlässigkeit des unterirdisehen Permafrostes war Null.

  • View HTML
    • Send article to Kindle

      To send this article to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

      Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

      Find out more about the Kindle Personal Document Service.

      Sub-sea permafrost regime at Prudhoe Bay, Alaska, U.S.A
      Available formats
      ×

      Send article to Dropbox

      To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

      Sub-sea permafrost regime at Prudhoe Bay, Alaska, U.S.A
      Available formats
      ×

      Send article to Google Drive

      To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

      Sub-sea permafrost regime at Prudhoe Bay, Alaska, U.S.A
      Available formats
      ×

Copyright

References

Hide All
Alexander, V., and others. 1975. Environmental studies of an Arctic estuarine system, ky V. Alexander 1and others]. Corvallis, Oregon, U.S. Environmental Protection Agency. (Final report. Grant R0811 24-03, ROAP/T ask 21 ARY/002, Program element IBA022.)
Gold, L. W., and Lachenbruch, A. H. 1973. Thermal conditions in perma frost-a review of North American literature. Permafrost. Second International Conference. 1328 July 1973, Yakutsk, U.S.S. R. North American contributioll. Washington, D. C., National Academy of Sciences, p. 3-25.
Harrison, W. D. 1972. Temperature of a temperate glacier. Journal of Glaciology, Vol. 11, No. 61, p. 1529.
Harrison, W. D., and Osterkamp, T. E. 1976 [a]. A coupled heat and salt transport model for subsea permafrost. Fairbanks, Alaska, Geophysical Institute, University of Alaska. (Report UAG R-247, Sea Grant Report 76-1 5.)
Harrison, W. D., and Osterkamp, T. E. 1976[b]. Theoretical models for sub-sea permafrost. (I/I Proceedings rifthe third International Conference on Port and Ocean Engineering under Arctic Conditions held in Fairbanks, Alaska, University of Alaska, 11-f 5 August 1975. Vol. 2. Fairbanks, Alaska, Institute of Marine Science, University of Alaska, p. (1011-24)
Lewellen, R.I. 1973. The occurrence and characteristics of nearshore permafrost, northern Alaska. Permafrost. Second International Conference. 1328 July 1973, raklltsk, V.S.S. R. North American contribution. Washington, D.C., Nationa l Academy of Sciences, p. 131-36.
Muller, S. W., comp. 1947. Permafrost, or permanently frozen ground, and related engineerillg problems. Ann Arbor, Mich., J. W. Edwards, Inc.
Muller-Beck, H. 1966. Paleohunters in America: origins and diffusion. Science, Vol. 152, No. 3726, p. 1191.
Osterkamp, T. E. 1975. A conceptual model of offshore permafrost. Fairbanks, Alaska, Geophysical Institute, University of Alaska. (Report UAG R-2 34.)
Osterkamp, T. E., and Harrison, W. D. 1976. Subsea permafrost at Prudhoe Bay, Alaska : drilling report and data analysis. Fairbanks, Alaska, Geophysical Institute, University of Alaska. (Report UAG R-245, Sea Grant Report 76-5.)
Osterkamp, T. E., and Harrison, W. D. In press. Subsea permafrost and its implications for offshore resource development. Northern Engineer.
Park, K. 1964. Partial equivalent conductance of electrolytes in sea water. Dee/J Sea Research, Vol. 11, No. 5, p. 729-36.
Reimnitz, E., and Barnes, P. W. 1974. Sea ice as a geologic agent on the Beaufort Sea shelf of Alaska. (In Reed, J. C., and Sater, J. E., ed. The coast and shelf of the Beaufort Sea. Proceedings of a symposium Oil Bea/Jort Sea coast and slzelfresearch. Arlington, Virginia, Arctic Institute of North America, p. 30 1-53.)
Rogers, J. C., and Sackinger, W. M. Unpublished. Investigations of Arctic offshore permafrost near Prudhoe Bay. Written 1976.

Sub-sea permafrost regime at Prudhoe Bay, Alaska, U.S.A

  • T. E. Osterkamp (a1) and W. D. Harrison (a1)

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed