Geomorphology and sediments of the inner continental shelf : Palm Beach to Cape Kennedy, Florida

Abstract

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).

Geomorphology, shallow structure, and sediments of the Florida inner continental shelf, Cape Canaveral to Georgia / by Edward P. Meisburger and Michael E. Field.

“…The red reflector was previously reported by Meisburger and Duane (1969) From near False Cape southward, a reflector judged to be continuous with the red reflector is directly underlain by unit F having seaward-dipping internal reflectors. Meisburger and Duane (1971) and Field and Duane (1974) The white reflector like the overlying primary reflectors slopes consistently eastward (Fig. 17).…”

“…Calcareous ooids, characteristic grain-types off Cape Canaveral, are absent from cores collected in this study, although they have been reported in deeper deposits seaward of the survey area by Terlecky (1967). Other calcareous grains reported farther to tlie south by Meisburger and Duane (1971) bases. Type F is finer, often contains a significant quantity of silt, and is less well sorted than type A sand.…”

“…General hthologic characteristics and shallow stratigraphic relationships of major sediment types on the north Florida inner shelf are summarized in Letters assigned to Uthologies are arbitrary and established for this program (Meisburger and Duane, 1971) to simphfy correlation and associations of sediment from one area to another. Therefore, type A sand is similar in character to sediments designated by that letter in the Fort Pierce-Cape Canaveral areas.…”

“…Fine shoreface sands similar to type F sediment are generally common to the south, but have not been given a letter designation in two ICONS studies of this region (Duane and Meisburger, 1969;Field and Duane, 1974). In the Fort Pierce area Meisburger and Duane (1971) identified the shoreface sands as type U sediment. In some respects type G sediments are similar to tlie semihthified calcarenite (designated Type E) mapped from Cape Canaveral soutli to Fort Pierce (Meisburger and Duane, 1971;Field and Duane, 1974).…”

“…In the Fort Pierce area Meisburger and Duane (1971) identified the shoreface sands as type U sediment. In some respects type G sediments are similar to tlie semihthified calcarenite (designated Type E) mapped from Cape Canaveral soutli to Fort Pierce (Meisburger and Duane, 1971;Field and Duane, 1974). However, no direct relationship has yet been established.…”