Heat Flow variations in Siberia and neighboring regions: A new look

Abstract

The present work deals with an updated evaluation of heat flow in Siberia (Asian part of Russia) and neighboring regions. It is based on results of geothermal measurements in more than 1680 boreholes and shallow measurements of bottom sediments in lakes localities in Siberia. Also considered are results of heat flow measurements in about 1500 sites in neighboring areas of China, Mongolia and Kazakhstan. Features of geological structures and development of adjacent regions have been factors considered in the evaluation of thermal regime of Siberia. Most of this territory is occupied by two broad platforms (West-Siberian and East-Siberian), markedly different in their thermal regimes. Heat flow in the West-Siberian plate averages 55–60 mW/m², sometimes rising to 70–80 mW/m². The East-Siberian platform is characterized by a predominance of low heat flow values in the range of 30–40 mW/m². The southern and eastern segments of these platforms are framed by mountain-folded areas (Sayano-Baikal, Transbaikal, Verkhoyano-Kolymskaya areas) with heat flow values (in the range of 70–80 mW/m²). These are formed mainly under the influence of mantle heat sources (asthenosphere upwellings and mantle diapirs). Analysis of temperature distributions shows that thermal conditions in the five-kilometer upper layer of rocks are determined by heat flow values. Nevertheless, the thermal field of the Asian part of Siberia has been insufficiently studied. The work also considers heat flow variations of adjacent regions located south of Siberia: Kazakhstan, Northern China and Mongolia.