Widespread occurence of mud mounds and associated BSRs on the Pacific margin off Nicaragua - results from a deep tow seismic survey


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mbreitzke [ at ] awi-bremerhaven.de

Abstract

During RV Sonne cruise SO173-1 in the framework of SFB574 (volatiles and fluids in Subduction zones) in July/August 2003, a new area offshore Nicaragua has been surveyed with the IFM-GEOMAR deep-towed multichannel seismic system (DTMCS). In total 13 NW-SE striking profiles running parallel to the continental slope were recorded at water depths between 1000 and 2500 m covering an area of approximately 700 square km. This study presents some new results from the ongoing investigations with these seismic profiles.The continental margin off Nicaragua is dominated by deeply incised canyons and numerous mound structures, as well as two large slides at the lower slope. Most of these mud mounds built positive topographic expressions (up to ca. 130 m) on the seafloor. They are characterized by transparent or semitransparent seismic facies in the cylinder like feeder channel tapering upward to cone shape geometry. The mud mounds are of different size and at different stages of development. The distribution of the mounds shows two distinct orientations (NW-SE and NE-SW) and is controlled by faults. The widespread occurrence of gas hydrate is imaged by a BSR visible in most parts of the survey area. Although the BSR has been identified over the entire area, it is variable along the seismic line in the frequency windows used (50-300 Hz). The BSR presents high to moderate amplitudes near the mud mounds or/and diapir structures and seems to disappear away from them. For the first time, our data show that the BSRs are continued but uplifted beneath some mud mounds.



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Conference (Talk)
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Not peer-reviewed
Publication Status
Published
Event Details
66. Jahrestagung der Deutschen Geophysikalischen Gesellschaft, 06-09 März, Bremen..
Eprint ID
14687
Cite as
Talukder, A. , Brückmann, W. , Bialas, J. , Kläschen, D. , Reston, T. and Breitzke, M. (2006): Widespread occurence of mud mounds and associated BSRs on the Pacific margin off Nicaragua - results from a deep tow seismic survey , 66. Jahrestagung der Deutschen Geophysikalischen Gesellschaft, 06-09 März, Bremen. .


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