Shallow Structural Characteristics of Florida Atlantic Shelf as Revealed by Seismic-Reflection Profiles: ABSTRACT

Abstract

ABSTRACT A sand resources survey off eastern Florida in 1965-66 by the U. S. Army Corps of Engineers' Coastal Engineering Research Center (CERC) resulted in the collection of 2,600 miles of seismic reflection profiles. With a penetration depth range of 0 to -500 feet MLW the profiles extend from nearshore (approximately 15-foot water depth) to a distance of 15 miles offshore. The records show several prominent acoustic reflecting horizons at shallow depth which can be traced over large areas of the nearshore continental shelf off east Florida. These areally extensive reflectors indicate some shallow structural features beneath the shelf surface; tentative stratigraphic correlations have been made in some cases with logged wells onshore. In the section revealed by CERC reflection records the dominant structural feature is an almost universal eastward dip of strata. Below about -100 to -200 feet MLW broad low relief undulations are common and appear to be of structural origin. Shallower subbottom strata are characterized by internal bedding features, erosional surfaces and a generally gentler eastward dip than the deeper section. The records show little apparent evidence of faulting with vertical displacement. Subbottom acoustic horizons on the CERC records are judged to represent a stratigraphic range from Eocene to Recent. Erosional surfaces and shallow water bedform features in the uppermost section are interpreted as resulting from Pleistocene sea level fluctuations.