2D modelling of fluid flow and heat transport during the evolution of the Baikal rift

Abstract

Hydrothermal anomalies of different scales and magnitudes have been observed at the sediment surface of the lake Baikal basin, and the presence of a thermal spring suggests that fluid circulation plays an important role in their formation. A 2D modelling study of sedimentation, fluid flow and heat flow in the Baikal rift basin undergoing flank uplift and basin subsidence has been performed in order to understand the impact of these processes on the surface heat flow and hydrothermal anomalies. The BASIN-code applied for the simulation allows for a topographically and compaction driven fluid flow coupled to heat transfer. The regional fluid circulation is an effective mechanism of heat redistribution when velocities in the basement are larger than several cm/yr. It reduces the heat flow in the flanks and increases the heat flow over the basin; heat is brought from the flanks towards the basin area, with largest fluid flow at a depth of 1–2km at both sides. The maximum computed heat fluxes are smaller than that measured in the heat flow anomalies. Nevertheless, the model suggests that fluid flow in the sedimentary basin combined with a topographically driven heat advection in the surrounding basement is a sufficient mechanism to account for the increased heat flow within the basin and the main features of the hot springs distribution.