The Inner Continental Shelf off eastern Florida was surveyed by CERC to obtain information on bottom morphology and sediments, subbottom structure, and sand deposits suitable for restoration of nearby beaches. Primary survey data consists of seismic reflection profiles and sediment cores. This report covers that part of the survey area comprising the inner Shelf between Palm Beach and Cape Kennedy. Sediment on beaches adjacent to the study area consists of quartzose sand and shell fragments. Median size of midtide samples generally lies in the range between 0.3 to 0.5 mm (1.74 to 1.0 phi) diameter. The Shelf in the study area is a submerged sedimentary plain of low relief. Ridge-like shoals generally of mediumto-coarse (0.25 to 1.0 mm) calcareous sand resting on the seaward dipping subbottom strata contain material suitable for beach restoration. A minimum volume of 92.2 x 10" cubic yards of suitable sand is available within study limits. FOREWORD This report is the second of a series which will describe CERC's exploration of the Inner Continental Shelf. The program (ICONS) has, the basic mission of finding offshore deposits of sand suitable for artificial beach restoration and nourishment. Edward P. Meisburger, staff geologist, and David B. Duane, Chief of the Geology Branch, prepared the report under the general supervision of George M. Watts, Chief of the Engineering Development Division. The field work was done by Alpine Geophysical Associates under contract (DA-08-123-CIVENG-65-57, modified).

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.

U. S. ARMY, CORPS OF ENGINEERS COASTAL ENGINEERING RESEARCH CENTER This document has been approved for public release and sale; its distribution is unlimited .

Tliis report is one of a continuing series which describes results of the Inner Continental Siiclf Sediment and Structure (ICONS) study. One aspect of the ICONS study is locating and delineating offshore sand and gravel deposits suitable for beach nourishment and restoration. The work was carried out under tlie coastal processes program of the U.S. Army

Beach nourishment Cape Fear, North Carolina Inner Continental Shelf Sediment deposits Seismic reflection profiles 20. ABSTRACT (Contlrxum oa r^veram •f«fi» If i imjc eeaary and identify by block number) The Inner Continental Shelf off the North Carolina coast between the South Carolina border and Cape Lookout, North Carolina, was surveyed to obtain information on bottom and subbottom sediment deposits and structures. The location and the extent of deposits of sand suitable for restoration and nourishment of nearby beaches were investigated. Primary survey coverage consisted of 824 kilometers (445 nautical miles) of seismic reflection survey and 139 cores ranging in length from 0.6 to 6.1 meters (2 to 20 feet). (continued) on '''^1 473 EDITION OF I MOV 65 IS OBSOLETE UNCLASSIFIED SECURITY CLASSIFICATIOK OF THIS PAGE (Whtm Data Entered) UNCLASSIFIED SECURITY CLASSIFICATION OF THIS P ACE(Whm Data Enlarad) More than half of the area surveyed is underlain by two thick sections of Coastal Plain sediments characterized by seaward-dipping progradational internal beds which generate a characteristic acoustic pattern on seismic reflection records. These beds are exposed on the shelf floor in places and elsewhere are covered by a thin sediment blanket.-Samples of these extensive units indicate that one is of Cretaceous age and the other of Oligocene age. Both units consist predominantly of fine quartz sand. Other sediment units closely underlying the shelf floor consist of planarto complex-bedded sheet and channel-fill deposits of predominantly quartz sand or biogenic calcium carbonate. These deposits range in age from Eocene to Holocene. Modern sediment accretion on the inner shelf appears to be largely restricted to the shoal fields off Cape Lookout and Cape Fear, and to inlet shoals along the coast. Elsewhere on the inner shelf floor, modern sediments are thin and discontinuous, and modem shelf processes appear to be largely confined to reworking, winnowing, and redepositing older deposits. UNCLASSIFIED SECURITY CLASSIFICATION OF THIS PAGEfHTien Data Entered) PREFACE This report is one of a continuing series which describe results of the Inner Continental Shelf Sediment and Structure (ICONS) study. One objective of the ICONS study is to provide geological information of the Inner Continental Shelf pertinent to the planning and design of engineering works and to a better understanding of geological aspects of the coastal zone as an engineering environment. Another objective of the ICONS study is to locate and describe offshore sand deposits suitable for beach nourishment and restoration (see Meisburger, 1977) The report was prepared by Edward P. Meisburger, a geologist in the Geotechnical Engineering Branch of CERC, under the general supervision of R.L. Rector and S.J. Williams, who served successively as Acting Chief of the Branch, and Dr. C.H. Everts, the present Chief. As part of the research program of the Engineering Development Division, the ICONS study was under the general supervision of G.M. Watts, former Chief o...