Thermal properties of sediments in the East Siberian Arctic Seas: A case study in the Buor-Khaya Bay. (January 2021)

• Record Type: Journal Article
• Authors: Chuvilin, Evgeny; Bukhanov, Boris; Grebenkin, Sergey; Tumskoy, Vladimir; Shakhova, Natalia; Dudarev, Oleg; Semiletov, Igor; Spasennykh, Mikhail
• Is Part Of: Marine and petroleum geology. Volume 123(2021)
• Publication Date: 2021-01
• Subjects: Shelf permafrost -- Sediments -- Thermal conductivity -- Heat capacity -- Temperature -- Particle size distribution -- Salinity -- Unfrozen water; Submarine geology -- Periodicals; Petroleum -- Geology -- Periodicals; Géologie sous-marine -- Périodiques; Pétrole -- Géologie -- Périodiques; Petroleum -- Geology; Submarine geology; Periodicals; Electronic journals; 551.468
• DOI: 10.1016/j.marpetgeo.2020.104672
• Languages: English
• ISSNs: 0264-8172

Abstract

Abstract: The temperature and thermal properties of shelf sediments from the East Siberian, Laptev, and Kara Seas were determined from field investigations. The sediments were in an unfrozen cryotic state (ice-free) and showed negative temperatures, ranging from −1.0 to −1.4 °C. These temperatures imply the presence of widespread subsea permafrost from the shelf to the continental slope of the East Siberian Arctic Seas, reaching ~1000–1500 km off the coast. The thermal conductivity and heat capacity of sediments (up to a depth of 0.5 m) from the Eastern Arctic Seas averaged 0.95 W/(m·K) and 3010 kJ/(m 3 ·K), respectively. We also conducted temperature and thermal conductivity measurements of the upper sediment horizons of the permafrost in the Laptev Sea shelf (drilling depth of 57 m). The analysis of sediment cores ensured the determination of thermal conductivity with depth. We also analyzed the influence of moisture content, density, particle size distribution, salinity, and thermal state on sediment thermal conductivity. The thermal conductivity of unfrozen cryotic (ice-free) sediments was predominantly dependent on the contents of silt and clay. In general, unfrozen cryotic sandy sediments had a thermal conductivity range 1.7–2.0 W/(m·K), a moisture content of ~20%, and a density of 2.0–2.2 g/сm 3 . Frozen (ice-containing) sediments showed higher thermal conductivities of 2.5–3.0 W/(m·K), with a density of 1.9–2.0 g/cm 3 and a moisture content exceeding 25–30%. The high thermal conductivity of sand was associated with low salinity (0.1–0.2%), high ice content, and moderate unfrozen water content. Highlights: The East Siberian Arctic Seas shelf sediments are in unfrozen cryotic state at temperatures, ranging from −1.0 to −1.4 °C. The thermal conductivity and heat capacity of shelf seafloor sediments averaged 0.95 W/(m·K) and 3010 kJ/(m 3 ·K), respectively. Thermal conductivity of cryotic sediments most strongly depends on the content of silt and clay, rather than moisture content. Thermal conductivity of subsea permafrost strongly depends on phase composition of pore water. Frozen shelf sediments are presented by low saline and ice-rich sandy sediments with thermal conductivity about 3.0 W/(m·K).