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Geothermal gradients in British lake sediments
Author(s) -
Pugh D. T.
Publication year - 1977
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1977.22.4.0581
Subject(s) - geothermal gradient , benthic zone , geology , bottom water , hydrology (agriculture) , intrusion , oceanography , heat flow , geothermal energy , environmental science , geochemistry , paleontology , geotechnical engineering , geography , meteorology , thermal
Temperatures have been measured in the water and sediments of Loch Ness and Windermere to investigate the possibility of determining the geothermal heat flow through the bottom of deep British lakes. The accuracy is limited by corrections for annual and long term variations in bottom water temperatures. In Loch Ness (max depth 232 m) the annual temperature variation of the deep water is normally <0.5°C. There is evidence of a benthic water layer overlying the sediments in the deepest parts of the loch in which the annual variations are probably not more than 0.2°C. When corrections are made, the mean of 13 measurements of heat flow in Loch Ness is 1.45 µ cal cm −2 s −1 . Values increase steadily from 1.03 µ cal cm −2 s −1 in the northeast to 1.74 in the southwest, with local high values near the Foyers granite intrusion. Annual variations in bottom water temperature in Windermere (max depth 65 m) are >2.5°C, though variations in the benthic layer are less than this. Reliable geothermal heat flow measurements were only possible because an extended series of measurements was available. The mean of three acceptable results was 1.69 µ cal cm −2 s −1 .