Geoacoustic investigations of cold vents and sedimentary processes at the active continental margin offshore Nicaragua.

Bürk, Dietmar (2007) Geoacoustic investigations of cold vents and sedimentary processes at the active continental margin offshore Nicaragua. Open Access (PhD/ Doctoral thesis), Christian-Albrechts-Universität, Kiel, Germany, 179 pp.

[thumbnail of 423_Bürk_2007_GeoacousticInvestigationsOfColdVents_Hschri_pubid10729.pdf]
Preview
Text
423_Bürk_2007_GeoacousticInvestigationsOfColdVents_Hschri_pubid10729.pdf - Published Version
Available under License German copyright act UrhG.

Download (89MB)

Abstract

Discharge of cold fluids from the seafloor into the ocean is known from many continental margins. The amount and mechanism of this fluid and volatile recycling are important factors for global mass balances. This work investigates cold vents and seeps in the forearc region of the active continental margin offshore Nicaragua with geoacoustic methods (multibeam bathymetry, deep-towed sidescan sonar, subbottom profiler). Ground truthing is available from camera system surveys and coring on several of the structures. The area is characterized by a high number of so-called mound structures visible in the multibeam bathymetry, and various intensity anomalies without a significant topographic expression but showing high backscatter in the sidescan sonar image. The increased backscatter on mounds and intensity anomalies is mainly related to an increased seafloor roughness, and attributed to hardgrounds like authigenic carbonate formations. A significant influence of the seafloor topography on the sidescan sonar signal is largely excluded. This is shown by a new processing algorithm, developed in this work. The detailed analysis of the seep sites suggests a classification into three end members and explains their formation through the interaction of several processes: Episodic fluid venting and associated authigenic carbonate formation, background sedimentation with subsidence, and erosion.

Document Type: Thesis (PhD/ Doctoral thesis)
Thesis Advisor: Götze, Hans-Jürgen and Reston, Timothy J.
Keywords: Meeresgeologie; Central America, Nicaragua, Continental slope, Cold vents, Mound structures, Geoacoustic, Multibeam, Sidescan sonar
Research affiliation: OceanRep > SFB 574 > A1
OceanRep > SFB 574
OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-GDY Marine Geodynamics
Kiel University
Refereed: No
Date Deposited: 10 Dec 2008 15:31
Last Modified: 05 Jan 2023 14:21
URI: https://oceanrep.geomar.de/id/eprint/4593

Actions (login required)

View Item View Item