HR: 1330h
AN: OS52B-0918    [PDF]
TI: Process Related Interpretation of Acoustic Data From the Hudson River Estuary
AU: * Nitsche, F O
EM: fnitsche@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964 United States
AU: Bell, R
EM: robinb@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964 United States
AU: Carbotte, S M
EM: carbotte@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964 United States
AU: Ryan, W B
EM: billr@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964 United States
AU: Flood, R D
EM: rflood@notes.cc.sunysb.edu
AF: SUNY Stony Brook University, Marine Sciences Research Center, Stony Brook, NY 11794 United States
AB: Acoustic surveying provides valuable information on the distribution of sedimentary environments in subaqueous settings. Frequently, differences in acoustic backscatter strength are used to distinguish sedimentary environments on the basis of their grain size composition. Here, we are presenting acoustic backscatter data from a section of the Hudson River Estuary that are better explained by sedimentary processes than by a variable such as sediment grain size distribution. Funded by New York State, the entire 240 kilometers of the Hudson River Estuary has been mapped using sidescan, chirp sub-bottom profiling, and multibeam bathymetry as part of the Benthic Mapping Project of the Hudson River Estuary Program. In additon, hundreds of gravity cores, and grab samples provide ground truth for a classification of the river bottom into discrete substrate types. Analyses of sedimentary environments reveal patterns in backscatter strength beyond those that can be related to the the sediment grain size distribution alone. Sediment classses can be distinguished based on internal volume scattering, compaction, scattering from surface roughness, scattering from aquatic plants and their roots, shelly substrates, and presense of gas bubbles. Many of the classes can be linked to dynamic processes including contemporary deposition, winnowing, erosion, and sediment migration in sand waves. To distinguish different classes and related processes we use the complete data sets. The results provide a better understanding of the dynamic processes of the Hudson River Estuary and improve the interpretation of the acoustic backscatter data from fine grained sedimentary environments.
DE: 3000 MARINE GEOLOGY AND GEOPHYSICS
DE: 3022 Marine sediments--processes and transport
DE: 3045 Seafloor morphology and bottom photography
DE: 4235 Estuarine processes
DE: 9330 Australia
SC: Ocean Sciences [OS]
MN: 2003 Fall Meeting