Geomorphology and sediments of the Chesapeake Bay entrance

Abstract

The entrance of the Chesapeake Bay and the Atlantic Ocean in the vicinity o£ Cape Charles and Cape Henry were surveyed to study the bottom morphology and sediments, and subbottom structure, in an effort to locate suitable sand deposits in volumes great enough to economically restore and periodically nourish the shore. Seismic reflection profiles and sediment cores were the basis for the study. Field and laboratory techniques used for the profiles and sediment obtained from the sea floor in lower bay and ocean are presented. Most of the study area is less than 35 feet deep; distribution of shallow bay and inshore terraces and deeper water are shown in the figures. The study included analyses of borings taken along the route of the Chesapeake Bay Bridge Tunnel by the Bridge Commission in 1960 and 1961. Cores obtained for a dredging study by the Norfolk District, Corps of Engineers, 1970, were made available and were used in the study. FOREWORD This report is one of a series which will describe results of the CERC Inner Continental Shelf Sediment and Structure (ICONS) Study, previously referred to as the Sand Inventory Program. Edward P. Meisburger, a CERC geologist, prepared the report under the direction and supervision of Dr. David B. Duane, Chief of the Geology Branch. As part of the research program of the Engineering Development Division the ICONS Study is under the general supervision of Mr. George M. Watts, Chief of the Division. The field work for the study was done by National Engineering Science Company (NESCO) under contract (DACW 65-68-0001) funded by CERC but awarded and administered by the Norfolk District, Corps of Engineers. Cores taken during the field program are stored at the Smithsonian Institution Oceanographic Sorting Center (SOSC) , Washington, D. C. 20390, Microfilm of the seismic profiles, the 1:80,000 navigational plots, and other ancillary data are stored at the National Oceanographic Data Center (NODC) , Rockville, Maryland 20852. Requests for information relative to these items should be directed to SOSC or NODC. At the time of publication Lieutenant Colonel Don S. McCoy was Director of CERC; Thomdike Saville, Jr. was Technical Director. NOTE: Comments on this publication are invited. Discussion will be published in the next issue of the CERC Bulletin.

Stratigraphic and geomorphic framework of uppermost Cenozoic deposits in the southern Delmarva Peninsula, Virginia and Maryland

“…These workers used data obtained from marine seismic reflection surveys and boreholes drilled for engineering tests for the Chesapeake Bay Bridge-Tunnel to map the configuration of the erosion surface at the top of the Tertiary section and to determine the shapes and trends of buried Pleistocene river channels. The character and sequence of lithic units composing the uppermost Pleistocene and Holocene sediment fill in the mouth of the modem Chesapeake Bay are remarkably similar to the older sedimentary sequence filling the Eastville paleovalley (see Meisburger, 1972, fig. 4; this report, fig.…”

“…The unconsolidated deposits of latest Pleistocene and Holocene age in the lowermost Chesapeake Bay area and the bay entrance have been studied by W. Harrison and others (1965) and Meisburger (1972). These workers used data obtained from marine seismic reflection surveys and boreholes drilled for engineering tests for the Chesapeake Bay Bridge-Tunnel to map the configuration of the erosion surface at the top of the Tertiary section and to determine the shapes and trends of buried Pleistocene river channels.…”

Proceedings of the 1988 U.S. Geological Survey Workshop on the geology and geohydrology of the Atlantic Coastal Plain

“…Additional unpublished core data were used to refine ide"'s about the locations and depths of the ancient channels of the Susquehanna River beneath the Delmarva Peninsula (Colman and . Boreholes in the bay itself are concentrated along the bridge and tunnel crossings (Ryan, 1953;Hack, 1957;Harrison and others, 1965) and near the bay mouth (Meisburger, 1972;Colman and Hobbs, 1987).…”

“…The Cape Charles paleochannel has been only partly filled by the Holocene transgression, and the channel itself is clearly related to the low sea-level stand associated with the last major glaciation, the late Wisconsinan. Radiocarbon ages from the channel fill range from about 8,000 to 15,000 yr before present (Harrison and others, 1965;Meisburger, 1972).…”

Reconnaissance high-resolution geophysical survey of the Monterey Bay, California, inner shelf; implications for sand resources

“…The suitability of these locations as potential borrow sites is dependent on a number of factors including size distribution, composition, and economics of recovery and placement (Meisburger, 1972). The most suitable borrow sand is one that approximates the size characteristics of the native beach material and is composed of particles of hard inorganic material (Meisburger, 1972).…”