Condutividade Térmica de Sedimentos da Plataforma Continental Sudeste do Brasil

Abstract

Thermal conductivity measurements have been carried out on 94 samples of platform sediments collected off the coast of São Paulo and Rio Grande do Sul States. The mean conductivity of these shelf sediments is 1.76 ± 0.40 W/m K and is thus considerably higher than those normally observed for deep sea sediments. The sediment conductivity is found to be strongly dependent on the type of sediments, its water content and degree of compaction. A general trend of decrease of conductivity with depth has been observed. Conductivity-porosity plot of the data shows that sand is a major constituent of platform sediments. Laboratory compaction studies indicate that conductivity increases linearly with the density, the rate of increase being lower for sediments rich in organic matter. Results of compaction studies have been pointed out as relevant in the investigation of such problems as reconstruction of paleotemperatures during the evolution of sedimentary basins, heat losses in submarine oil pipes and radioactive waste disposal in sea floors.