Heat flow and heat conductivity coefficient measured in bottom sediments collected in Cruise 13 of R/V Akademik Sergey Vavilov in the Pechora Sea

In Cruise 13 of R/V Akademik Sergey Vavilov in the Pechora Sea, six heat flow varied from 50 to 75 mW/m**2. Deep heat flow in the Pechora Sea was calculated equal to 45 mW/m**2, which is confirmed by results of geological and geophysical studies and corresponds to Middle Baikal age of the basement. A model of structure of the lithosphere in the Pechora Sea is suggested. Total thickness of the lithosphere in the basin (190 km) determined from geothermal data agrees well with that in transition zones from the continent to the ocean. According to estimates of deep heat flow in the region obtained, thickness of the mantle (160 km), of the basaltic (15 km), and of the granitic (15 km) layers of the lithosphere were also evaluated. Temperature values at boundaries of the sedimentary layers were calculated over a geological and geophysical profile crossing the Pechora Sea basin. Temperatures obtained agree with the temperature interval of hydrocarbon generation and correspond to Permian-Triassic sedimentary sequences, which are the most productive ones in the Pechora Sea region from the point of view of oil and gas potential.

(Table 1) Sediment characteristics at DSDP Hole 75-532A

Orientation and geometry of pores as well as sediment compressibility can be approximated by determining the shrinkage behavior of standardized samples. The sections investigated show that these measurements are influenced by changing sediment composition. This is also well documented by the relationship between void ratio and overburden pressure. Median pore-diameter calculations clearly reflect both sediment composition and compaction.