U.S. Geological Survey Open-File Report 02-002
Geological Framework Data from Long Island Sound, 1981-1990:
A Digital Data Release
Coring Program Discussion and Results
Two major vibratory coring programs have been conducted in Long Island Sound, and their results are included
in this report. Both programs were conducted aboard the
ATLANTIC TWIN, a twin-hulled vessel of approximately 40-ton displacement, and used an Alpine Geophysical Associates, Inc. pneumatic, vibrating hammer-driven coring assembly. In this device, the vibrator sits atop a core pipe made of standard 4-inch steel pipe.
A metal H-beam, supported by four legs, serves as a support tower and a guide for the vibrator and core pipe. This coring device has the advantage of being able to recover long, continuous, relatively-undisturbed samples of the sea floor. The cores were collected in 3.5-inch diameter plastic-liner tubes. In the laboratory, the cores were split lengthwise into working and archive halves for sampling and photography.
The first major coring program in the Long Island Sound was conducted through the Inner Continental Shelf Sediment and Structure (ICONS) program of the U.S. Army Corps of Engineers Coastal Engineering and Research Center (CERC). This program, which collected 75 vibratory cores (Figure 1), was directed toward mapping sand resources suitable for beach restoration, determination of regional engineering properties of shelf sediments, and effects of ocean dumping (Williams, 1981). These cores were subsequently redescribed in detail at Hampton University with funding from the USGS (Andrew Grosz, USGS, oral communication, 2001) to make them more useful for delineations of shelf structural characteristics and analyses of shelf history and sediment sources. Cores recovered from the Sound ranged from 1.3 to 5 m in length, and were collected in water depths that ranged from 3 to 30 m.
The second major coring program was conducted between 1984-1988 as part of a cooperative between the Minerals Management Service (MMS) of the U.S. Department of the Interior, the State of Connecticut, and the Association of American State Geologists (AASG). The purpose of this program was to investigate the geology of the inner continental shelf off southern New England. In Long Island Sound, this effort was focused on verification of the systematic high-resolution seismic-reflection surveys collected as part of a cooperative between the State of Connecticut and the U.S. Geological Survey. As part of this program, 13 vibratory cores were collected at 14 locations on the seismic lines during 1984 (Figure 2). During 1988, 8 cores were collected in Long Island Sound and 3 cores were collected in Block Island Sound, all on the existent seismic lines. Although not shown in figure 2, 3 cores on this cruise were also collected further east in Rhode Island Sound. Cores recovered ranged from 1.4 to 8.5 m in length.