Active hydrate destabilization in Lake Baikal, Siberia?

Abstract

ABSTRACT In this paper, we present new seismic and heat‐flow data that show the base of the hydrate stability zone (BHSZ) in Lake Baikal to be locally characterized by abnormal variations in depth, with distinct regions of deeper‐than‐normal and regions of shallower‐than‐normal BHSZ. These variations are related to strong lateral variations in heat flow, and occur in close association with important rift‐basin faults. Areas of shallow BHSZ are also characterized by the presence of several methane seeps and mud volcanoes at the lake floor. We infer that the seeps are the surface expression of escape pathways for overpressured fluids generated by the dissociation of pre‐existing hydrates, in response to a thermal pulse caused by an upward flow of hydrothermal fluids towards the BHSZ. It thus seems that present‐day hydrate dissociation in Lake Baikal is modulated by the tectonic activity in the rift rather than by – climatically controlled – changes in lake level or water temperature.