SOME REMARKS ON THE THERMAL NATURE OF THE DOUBLE BSR

Abstract

The numerical solution of the heat transfer problem, which takes into account the latent heat (Stefan problem) of the gas hydrate dissociation, shows that the "double BSR" at the Nankai Trough site could have been caused by the upwards displacement of a previously deeper phase boundary (base of the gas hydrate stability zone) after an abrupt increase of the sea-bottom temperature by approximately 4 °C or more, which happened about 10 ka ago. The obtained conclusions are believed to be correct for other areas of the Ocean as well, where two or more BSRs have been observed. In order to explain the nature of the phenomenon of the "double BSR" it is necessary to examine also other factors besides paleooceanographic ones, for example, lithological-geochemical properties of sediments. © 2006.