A Side Scan Sonar and Sub-Bottom Profiler Study Over Buried River Channels, Chesapeake Bay.
Abstract
This study used a sub-bottom profiler and side-scan sonar to study the most recent Holocene channels in the mid-Chesapeake Bay near Annapolis, MD. Nearly two dozen transects collected approximately 150km of sub-bottom and 90km of side scan data. Analysis of the sub-bottom data suggests three strong sub-bottom returns separate four sub-bottom layers. They are found at depths between 1.5m and l4m below the sediment/water interface. Channels cut into some of these layers have a north-south orientation. Analysis of the side scan data and bathymetric profiles indicates that the orientation of the sub-bottom layering tends to follow the general bottom surface bathymetry and orientation of the present channel. Bottoms surface morphology does not appear to reflect sub-bottom characteristics. Both side scan and sub-bottom data reflect sediment deposition. Sedimentation in the study area, south of the turbidity maximum in the Chesapeake Bay, is approximately 0.05 cm/yr to 0.075 cm/yr. This estimate uses the measured layer thickness and assumes that the deepest sub-bottom retum separating the two deepest layers represents the 18,000 year old Cape Charles paleochannel. This seems plausible since the layering conforms to the depth and location of the Cape Charles paleochannel previously determined.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1998
- Accession Number
- ADA359089
Entities
People
- Dewey A. Lopes
Organizations
- United States Naval Academy