Thermal State of Lithosphere and New Temperature Measurements at Knipovich Ridge and NW Barents Sea Margin

Abstract:

We present new in-situ temperature measurements, integrated with the gravity and piston coring results, from a recent expedition onboard icebreaker Kronprins Haakon in October-November 2019.

The study region is located in a narrow passage between Svalbard and the Greenland shelf formed by seafloor spreading along the Knipovich Ridge during the last 10 Myr. Here, the interaction between the Eurasian and North American lithospheric plates results in a complex tectonic environment varying from oblique extension to shear deformation. The NW Barents Sea margin and Svalbard, located a few 100 km’s east of the plate boundary, evidenced concurrent volcanism, uplift and erosion during the Neogene-Quaternary times.

We used miniature ANTARES temperature probes to collect in situ temperature data at 15 ship stations (for site location see Figure). At each site, we used 4-7 probes placed in steel fins outside of the core barrel. In addition, we calibrated temperature sensors versus a pair of high-precision thermistors in the CTD probe to achieve a higher data accuracy at each site. The temperature probes were also accompanied with tilt and pressure-depth sensors.

There are a number of factors controlling the temperature distribution in shallow sediments in the study region such as hydrothermal circulation, ocean currents, intense sedimentation due to glacial erosion and the deep geothermal heat flux. These processes regulate the release of methane and other gases from the seabed.

The surface heat flow data will provide new constraints into the tectonic structure of the lithosphere, and will be useful for assessing methane hydrate distribution and prospectively for hydrocarbons. Since measurements in the Arctic Ocean are still sparse, we enhance the existent database of heat flow measurements and aim towards ground-truthing existing lithospheric thermal models of the polar North Atlantic region.