Ten Years of icy Data Show the Flow of Heat from the Arctic Seafloor
Arthur T Knackerbracket has found the following story:
Scientists have taken the temperature of a huge expanse of seafloor in the Arctic Ocean in new research by the U.S. Geological Survey and the Geological Survey of Canada. The study, published in the Journal of Geophysical Research, is accompanied by the release of a large marine heat flow dataset collected by the USGS from an ice island drifting in the Arctic Ocean between 1963 and 1973. These never-before-published data greatly expand the number of marine heat flow measurements in the high Arctic Ocean.
Marine heat flow data use temperatures in near-seafloor sediments as an indication of how hot Earth's outer layer is. These data can be used to test plate tectonic theories, provide information on oil and gas reservoirs, determine the structure of rock layers and infer fluid circulation patterns through fractures in those rock layers.
Starting in 1963, now-retired USGS scientist Arthur Lachenbruch and his team of researchers conducted 356 marine heat flow measurements and acquired more than 500 seafloor sediment samples while working from a hut installed on Fletcher's Ice Island, a 30-square-mile ice floe also known as T-3. These Arctic Ocean heat flow measurements taken by the USGS over the course of 10 years represent far more than the number available for the U.S. Atlantic margin.
[...] In the Journal of Geophysical Research paper describing these measurements, USGS geophysicist Carolyn Ruppel and co-authors combine the legacy T-3 heat flow data with modern seismic images. These Arctic Ocean seismic data are acquired by icebreakers taking images hundreds to thousands of meters (up to many miles) below the seafloor to reveal sediment and rock structures, faults, and other features.
[...] The new paper analyzes the variability in the T-3 heat flow dataset and shows that the temperatures of the seafloor and upper levels of the crust are not dependent on bathymetry or sediment thickness. The analysis also shows that high heat flow variability on Alpha Ridge, which was formed when a mantle hotspot triggered the creation of the High Arctic Large Igneous Province, is consistent with thin sediment cover over fractured basement rock permeated by circulating fluids.
The new study also confirms results obtained in the 1960s by Lachenbruch and USGS colleague B. Vaughn Marshall. They had postulated that differences between the make-up of the rock layers between Canada Basin and Alpha Ridge could account for a heat flow anomaly at the boundary between these provinces.
C. D. Ruppel, A. H. Lachenbruch, D. R. Hutchinson, R. J. Munroe, D. C. Mosher. Heat Flow in the Western Arctic Ocean (Amerasian Basin). Journal of Geophysical Research: Solid Earth, 2019; DOI: 10.1029/2019JB017587
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