This model of geothermal heat flow was obtained as a result of studying the thermal structure of the Arctic lithosphere using a set of geophysical data. The study of geothermal heat flow is important for calculating the long-term sustainability of engineering structures and assessing potential greenhouse gas emissions from permafrost thawing, so these studies are especially important for high-latitude regions. Heat flow data is also needed to estimate potential geothermal energy reserves. However, the data obtained by direct measurements are not enough to compile a detailed map of the heat flow for most of the Arctic region.

To construct a new heat flow map for the study region, the International Heat Flow Commission [IHFC] catalog was used as the initial approximation as heat flow data (Fig. 1). However, this database contains large gaps. To fill these gaps, theoretical models of the global heat flow [Davies, 2013; Lucazeau, 2019] were used, which are based on the interpolation of measured data o take into account the structure of the lithosphere (Fig. 2, A, B).









Figure 1. Location and values of direct heat flow measurements [IHFC 2021 database, Fuchs et al., 2021]

A method for estimating the surface heat flow using inversion of seismic and magnetic data, supported by direct measurements is described in [Petrunin et al., 2022]. This approach allows for using all available indirect data on the thermal structure of the lithosphere to build a thermal model by the optimization method and minimize errors arising from uncertainty of input data. The resulting heat flow map (Fig. 2C) agrees well with the observational data and correlates with lithospheric domains of different tectonic history and age correspondingly. The new map reveals some features that were not identified earlier (as seen in figures 2A, 2B, and 2C). In particular, zones of elevated heat flow in the Bering Strait, Chukchi Sea, and a residual anomaly in the area of the Mid-Labrador Ridge, which was active in the Paleogene. The new data also clearly show an increase in heat flow in the ancient rift zone separating Eastern and Central Siberia, which is not visible on maps published earlier.