Subsurface temperatures and geothermal gradients on the north slope of Alaska

Timothy S. Collett; Kenneth J. Bird; Leslie B. Magoon

doi:10.1016/0165-232x(93)90071-f

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USGS · 70018274

Subsurface temperatures and geothermal gradients on the north slope of Alaska

Timothy S. Collett·Kenneth J. Bird·Leslie B. Magoon

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Abstract

On the North Slope of Alaska, geothermal gradient data are available from high-resolution, equilibrated well-bore surveys and from estimates based on well-log identification of the base of ice-bearing permafrost. A total of 46 North Slope wells, considered to be in or near thermal equilibrium, have been surveyed with high-resolution temperatures devices and geothermal gradients can be interpreted directly from these recorded temperature profiles. To augment the limited North Slope temperature data base, a new method of evaluating local geothermal gradients has been developed. In this method, a series of well-log picks for the base of the ice-bearing permafrost from 102 wells have been used, along with regional temperature constants derived from the high-resolution stabilized well-bore temperature surveys, to project geothermal gradients. Geothermal gradients calculated from the high-resolution temperature surveys generally agree with those projected from known ice-bearing permafrost depths over most of the North Slope. Values in the ice-bearing permafrost range from ≈ 1.5° C 100 m "> ≈1.5°C100m in the Prudhoe Bay area to ≈ 4.5δ C 100 m "> ≈4.5 δ C100m in the east-central portion of the National Petroleum Reserve in Alaska. Geothermal gradients below the ice-bearing permafrost sequence range from ≈ 1.6° C 100 m "> ≈1.6°C100m to ≈ 5.2° C 100 m "> ≈5.2°C100m .

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Source-reported bounding extent: 65.87803877813585° to 71.69388395024325° latitude; -167.08712006649446° to -143.85405574285585° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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Timothy S. Collett, Kenneth J. Bird, Leslie B. Magoon. 1993. Subsurface temperatures and geothermal gradients on the north slope of Alaska. https://doi.org/10.1016/0165-232x(93)90071-f

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