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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.author Furlong, Jonathan
dc.date.accessioned 2013-06-11T22:31:13Z
dc.date.available 2013-06-11T22:31:13Z
dc.date.copyright 2013 en_US
dc.date.issued 2013-06-11
dc.identifier.uri http://hdl.handle.net/1828/4648
dc.description.abstract In 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.language English eng
dc.language.iso en en_US
dc.subject Autonomous en_US
dc.subject Cascadia en_US
dc.subject Cold Vent en_US
dc.subject Gas Hydrate en_US
dc.title Characteristic morphology, backscatter, and sub-seafloor structures of cold-vents on the Northern Cascadia Margin from high-resolution autonomous underwater vehicle data en_US
dc.type Thesis en_US
dc.contributor.supervisor Riedel, Michael
dc.contributor.supervisor Spence, George D.
dc.degree.department School of Earth and Ocean Sciences en_US
dc.degree.level Master of Science M.Sc. en_US
dc.rights.temp Available to the World Wide Web en_US
dc.description.scholarlevel Graduate en_US
dc.description.proquestcode 0373 en_US
dc.description.proquestcode 0374 en_US


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