Marine Biodiversity and Ecosystem Functioning
EU Network of Excellence

 
Main Menu

· Home
· Contacts
· Data Systems
· Documents
· FAQ
· Links
· MarBEF Open Archive
· Network Description
· Outreach
· Photo Gallery
· Quality Assurance
· Register of Resources
· Research Projects
· Rules and Guidelines
· Training
· Wiki
· Worldconference

 

Register of Resources (RoR)

 People  |  Datasets  |  Literature  |  Institutes  |  Projects 

[ report an error in this record ]basket (0): add | show Print this page

Multi-frequency seismic study of the gas hydrate accumulations in Lake Baikal, Siberia
Vanneste, M.; De Meersman, K.; Guidard, S.; Versteeg, W.; Golmshtok, A.; Kremlev, A.; De Batist, M. (2001). Multi-frequency seismic study of the gas hydrate accumulations in Lake Baikal, Siberia. Geophys. Res. Abstr. 3(780)
In: Geophysical Research Abstracts. Copernicus: Katlenburg-Lindau. ISSN 1029-7006; e-ISSN 1607-7962
Peer reviewed article  

Available in  Authors 
Document type: Summary

Authors  Top 
  • Vanneste, M.
  • De Meersman, K.
  • Guidard, S.
  • Versteeg, W.
  • Golmshtok, A.
  • Kremlev, A.
  • De Batist, M.

Abstract
    Recently, the presence of methane hydrates has been evidenced in Lake Baikal, Siberia, by means of seismic profiling, deep drilling and shallow coring. This is -up to now- the only reported occurrence of gas hydrates in a confined fresh-water basin. In this presentation, we discuss the frequency-dependent acoustic characteristics of the hydrate-bearing sediments, using 5 different types of reflection seismic data encompassing frequencies from 10 to 1000 Hz. On low-frequency airgun-array data, the base of the hydrate stability zone (HSZ) is observed as a single, high-amplitude, inverse-polarity reflection that often crosscuts the local stratigraphy. Amplitude and continuity of the BSR decrease or even disappear on higher-frequency data. On medium- to high-frequency data (e.g. watergun) the base of the HSZ is no longer expressed as a single reflector, but rather as a facies change between enhanced reflections below and blanked reflections above. The increasing reflection amplitude of the BSR with increasing offset (AVO-analysis), the high reflection coefficient of the BSR (-40 % of lake floor reflection) and the presence of enhanced reflections beneath the BSR suggest the presence of free gas below the HSZ. The observation of some enhanced reflections extending into the HSZ could even indicate that free gas may co-exist with hydrates within the HSZ. Blanking of the reflection amplitudes above the BSR is variable. Instantaneous frequency analyses reveal a low-frequency shadow beneath the BSR. We also collected lake-bottom reflection/refraction data, using GEOMAR's "Ocean-Bottom Hydrophones". Several profiles were recorded with a medium-resolution single airgun with sufficient energy to penetrate below the HSZ. The velocity information obtained from these measurements shows a distinct low-velocity layer below the base of the HSZ. Above, several higher-velocity layers are recognised. Modelling of interval velocities in this zone indicate hydrate presence of 5 to 8 % of pore volume. We also acquired new medium-frequency, single-channel airgun data at the BDP-1997 site (Baikal Drilling Project), providing the first acoustic images from this location. Hydrates (10 % pore volume) were retrieved from 121 and 160 m sub-bottom depth, but still about 200 m above the base of the local hydrate stability field. Remarkably, the seismic data at the drilling site show no indications for the presence of hydrates at the hydrate-recovery depths (no acoustic blanking, no BSR). These results were used to roughly estimate the amount of carbon stored in the Lake Baikal hydrate reservoirs, showing that most probably they do not form a future energy resource.

All data in the Integrated Marine Information System (IMIS) is subject to the VLIZ privacy policy Top | Authors 


If any information here appears to be incorrect, please contact us
Back to Register of Resources
 
Quick links

MarBEF WIKI

Erasmus Mundus Master of Science in Marine Biodiversity and Conservation (EMBC)
Outreach

Science
Responsive Mode Programme (RMP) - Marie Nordstrom, copyright Aspden Rebecca

WoRMS
part of WoRMS logo

ERMS 2.0
Epinephelus marginatus Picture: JG Harmelin

EurOBIS

Geographic System

Datasets

 


Web site hosted and maintained by Flanders Marine Institute (VLIZ) - Contact data-at-marbef.org