Linking surficial geomorphology with vertical structure in high and low energy marine environments
Presentation Abstract
The inland waters of the Puget Sound, Washington, USA, and Georgia Basin, British Columba, Canada, is a complex system of high energy river inputs to lower energy large basins with direct connection to the open ocean through the Straits of Juan de Fuca. High energy systems acting as transport mechanisms for coarse sediment interact with low energy regions with transport deposition of finer sediments to create the vertical stratigraphy of the seafloor. In regions of high energy the seafloor expression is dominated by a rougher seafloor with more geomorphic features of coarser material, while low energy regions are expressed in a seafloor of uniform lamination. This research investigates the link between the surface expression of seafloor roughness and the underlying vertical structure of sediment deposition. Using a high resolution bathymetric surface derived from multibeam sonar synchronized with low frequency sub-bottom acoustic profiles, the depth of acoustic penetration is correlated with a focal calculation of seafloor roughness. Areas of lower acoustic impedance have a larger range in penetration, with lower ranges of penetration persisting in areas of high acoustic impedance. High acoustic impedance is indicative of harder sediments, such as sand, and low acoustic impedance indicates softer sediments, such as mud. The research is a comparative study between a high energy system adjacent to the mouth of the Elwha River and the low energy protected region of South Possession Sound. The research illustrates the strong link between seafloor geomorphology and the terrestrial sources of sediment input and mitigation of sediment transport energy.
Session Title
Remote sensing technology to monitor the short and long term dynamic of the Salish Sea
Conference Track
Habitat
Conference Name
Salish Sea Ecosystem Conference (2016 : Vancouver, B.C.)
Document Type
Event
Start Date
2016 12:00 AM
End Date
2016 12:00 AM
Location
2016SSEC
Type of Presentation
Poster
Genre/Form
conference proceedings; presentations (communicative events); posters
Contributing Repository
Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.
Subjects – Topical (LCSH)
Geomorphology--Salish Sea (B.C. and Wash.); Marine ecology--Research--Salish Sea (B.C. and Wash.)
Geographic Coverage
Salish Sea (B.C. and Wash.)
Rights
This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.
Type
Text
Language
English
Format
application/pdf
Linking surficial geomorphology with vertical structure in high and low energy marine environments
2016SSEC
The inland waters of the Puget Sound, Washington, USA, and Georgia Basin, British Columba, Canada, is a complex system of high energy river inputs to lower energy large basins with direct connection to the open ocean through the Straits of Juan de Fuca. High energy systems acting as transport mechanisms for coarse sediment interact with low energy regions with transport deposition of finer sediments to create the vertical stratigraphy of the seafloor. In regions of high energy the seafloor expression is dominated by a rougher seafloor with more geomorphic features of coarser material, while low energy regions are expressed in a seafloor of uniform lamination. This research investigates the link between the surface expression of seafloor roughness and the underlying vertical structure of sediment deposition. Using a high resolution bathymetric surface derived from multibeam sonar synchronized with low frequency sub-bottom acoustic profiles, the depth of acoustic penetration is correlated with a focal calculation of seafloor roughness. Areas of lower acoustic impedance have a larger range in penetration, with lower ranges of penetration persisting in areas of high acoustic impedance. High acoustic impedance is indicative of harder sediments, such as sand, and low acoustic impedance indicates softer sediments, such as mud. The research is a comparative study between a high energy system adjacent to the mouth of the Elwha River and the low energy protected region of South Possession Sound. The research illustrates the strong link between seafloor geomorphology and the terrestrial sources of sediment input and mitigation of sediment transport energy.
