Characteristic morphology, backscatter, and sub-seafloor structures of cold-vents on the Northern Cascadia Margin from high-resolution autonomous underwater vehicle data

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dc.contributor.authorFurlong, Jonathan
dc.contributor.supervisorRiedel, Michael
dc.contributor.supervisorSpence, George D.
dc.date.accessioned2013-06-11T22:31:13Z
dc.date.available2013-06-11T22:31:13Z
dc.date.copyright2013en_US
dc.date.issued2013-06-11
dc.degree.departmentSchool of Earth and Ocean Sciencesen_US
dc.degree.levelMaster of Science M.Sc.en_US
dc.description.abstractIn this thesis seafloor cold vents are examined using autonomous underwater vehicle (AUV) and remotely operated vehicle (ROV) data on the Northern Cascadia margin. These data were collected in a 2009 joint cruise between the Monterey Bay Aquarium Research Institute (MBARI) and Natural Resources Canada (NRCan). High- resolution bathymetry data, acoustic reflectivity (backscatter) data, and 3.5 kHz sub bottom profiler data were examined for cold-vent-related features that include pockmarks, chemosynthetic biological communities (CBC), and authigenic carbonate. Additionally subsequent ROV observations, sediments from push cores and seafloor video/photos were used to ground truth AUV data. Numerous prolific venting sites were examined in detail and a model for the evolution of venting was generated. Vents are categorized as juvenile, intermediate, or mature depending on the presence and or absence of cold-vent-features. High near-surface reflection amplitudes are coincident with an anomalous area of seafloor backscatter. In June of 2012, NEPTUNE (North East Pacific Time-series Underwater Networked Experiment) collected a near-surface push core with their ROV ROPOS (Remotely Operated Platform for Ocean Sciences) in the high reflective area. The retrieved core showed stacked turbidites in the top 0.5 meters of the sediment column. Closely spaced high-velocity turbidite sands are highly reflective and inhibit acoustic penetration to depth. The presence of high-density, high-velocity sands in the near surface is linked to steady ocean bottom currents. These bottom currents progress northeast to southwest over the study area and differentially erode the surface sediments by removing muds and leaving heavy sands over the exposed area.en_US
dc.description.proquestcode0373en_US
dc.description.proquestcode0374en_US
dc.description.proquestemailjonfurlong@hotmail.comen_US
dc.description.scholarlevelGraduateen_US
dc.identifier.urihttp://hdl.handle.net/1828/4648
dc.languageEnglisheng
dc.language.isoenen_US
dc.rights.tempAvailable to the World Wide Weben_US
dc.subjectAutonomousen_US
dc.subjectCascadiaen_US
dc.subjectCold Venten_US
dc.subjectGas Hydrateen_US
dc.titleCharacteristic morphology, backscatter, and sub-seafloor structures of cold-vents on the Northern Cascadia Margin from high-resolution autonomous underwater vehicle dataen_US
dc.typeThesisen_US

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