Ninth international conference on - Marum

Abstracts of posters 101
effect combined with a dynamic hydrate system; and (3) infiltration of cold lake water, possibly induced by local
convection and/or water segregation.
69
88
29
43
52
78 85
44 114 77
85
80
80
43
76
68 54
67
Fig. 1. (a) Lake Baikal Rift DEM view from the north with location of Kukuy mud volcano area in
Central Basin. (b) Kukuy K-2 mud volcano with measured thermal gradients (in mK/m) and stations
were hydrates were cored in red. Remark that sites with hydrates returned mostly anomalous small
thermal gradients with increased thermal gradients at nearby sites.
Fig. 2. To explain the distribution of gas hydrates and thermal gradient anomalies as observed in K-2 mud
volcano, we propose a model were the formation of impermeable hydrate lumps locally blocks and diverts
the upflow of warm seep fluids, while continued water segregation associated with the hydrate formation
induces infiltration of cold sea water from above.
The localized occurrence of hydrates within the mud volcanoes and a close relation to thermal anomalies was
also observed in the mud volcanoes “Malenkiy” and “Bolshoy”, located at a water depth of about 1380m. More
than 30 gravity cores in both structures indicate zones with shallow hydrates in local depressions and on
culminations. Thermal stations show the presence of anomalous thermal gradients, up to 180 mK/m, at short
distances of background values.
The mud volcanoes in Lake Baikal do not display a strong activity in terms of acoustic flaring in the water
column (almost absent) and large-scale temperature anomalies (< 1 degrees C). However, they comprise local
shallow hydrate systems in close association with anomalous low and high thermal gradients. We will compare
the Baikal results with thermal signatures from hydrate-containing seeps and mud volcanoes in the Gulf of
Cadiz, the Black Sea, the Sea of Okhotsk and the Hikurangi Margin.
This work was supported by the Bilateral Flanders-Russian Federation Project: Gas hydrate accumulations
associated with active fluid seeps: a combined thermal and acoustic approach.
References
Kida, M., Khlystov, O., Zemskaya, T., Takahashi, N., Minami, H., Sakagami, H., Krylov, A., Hachikubo, A.,
Yamashita, S., Shoji, H., Poort, J. and Naudts, L., 2006. Coexistence of structure I and II gas hydrates in
Lake Baikal suggesting gas sources from microbial and thermogenic origin. Geophys. Res. Lett.,
33(24).
b.
500 m
53
61