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Geological > Geologic Investigations > Introduction


Our purpose is to provide you with a central location for access to a body of information relating to the geology of Long Island Sound and its surroundings. Much of this information has been developed over the past 24 years through a program of marine geologic investigations coordinated by the State Geological and Natural History Survey of Connecticut (State Survey). These investigations are, in large part, a marine extension of the systematic land-based effort to map the geology of Connecticut that was begun cooperatively with the U.S. Geological Survey (U.S.G.S.) in 1950's. (See Background Section for history and a guide to terrestrial work relating to the Sound). As with any such endeavor, the work of the State/U.S.G.S. "cooperative" has benefited greatly from the contributions of previous and contemporary individual workers (See Previous and Related Work Section), and important partners including the U.S. Minerals Management Service (M.M.S.), The National Undersea Research Center (N.U.R.C.) at UCONN-Avery Point, N.O.A.A.'s Atlantic Hydrographic Branch and students and faculty from the following colleges and universities: Boston University, Mount Holyoke College, S.U.N.Y.-Stony Brook, U.S. Coast Guard Academy, University of Connecticut, University of New Haven, University of Rhode Island, Vrije Universitiet (Amsterdam), Wesleyan University and Williams College. (See Collection Methods and Results Sections).


Speculation concerning the geologic origins of Long Island Sound began to appear in the scientific literature during the latter part of the 19th century (e.g., Dana, 1875, 1890; Hollick, 1893). Geologic inferences regarding the Sound remained rooted in extrapolations from on-land evidence throughout the first half of the 20th century (e.g., Antevs, 1922; Reeds, 1927). The technological advances that occurred during and after World War II, provided a means to test and augment the musings of earlier workers with subbottom and magnetic data that could be collected in the Sound itself (e.g., Oliver and Drake, 1951; Zurflueh, 1962). For further information regarding acoustic data collection systems, like those shown below, and other geophysical tools see Collection Methods.

Figure courtesy of the United States Geological Survey.

Work conducted in the 1960s and 1970s, provided a partial understanding of the Sound's history (e.g., Newman and Fairbridge, 1960; Grim et al. 1970; McMaster and Ashraf, 1973a; Haeni and Sanders, 1974; Feldhausen and Ali, 1976; Dehlinger, 1978), and by the late 1970s, glacial lake and other glacial and marine deposits in the vicinity of Long Island Sound had been sampled (e.g., Frankel and Thomas, 1966; McCrone, 1966; Akpati, 1974; Bertoni et al. 1977). For a more complete overview of the history of geologic investigations in Long Island Sound see Lewis and Stone, 1991, and Lewis and DiGiacomo-Cohen, 2000. A bibliography of selected previous and related geologic work in and around Long Island Sound is provided in the References Section.

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The State Geological and Natural History Survey of Connecticut was established in 1903 with a general charge from the Legislature to advance "knowledge of the geology, botany and zoology of the state" through field investigations, mapping, and publication of findings. From its inception through the late 1940's, the geologic work of the State Survey was often accomplished through individual, periodic cooperative investigations involving the U.S. Geological Survey (U.S.G.S.) and investigators from the state's colleges and universities. During the 1950s and early 1960s a more formal relationship had been developed with the U.S.G.S. and the academic community. A long-term, "cooperative" program of systematic bedrock and glacial geologic mapping in Connecticut was developed under the direction of Dr. Joe Webb Peoples. By the early 1980s, quadrangle-scale (1:24,000) bedrock and surficial geologic information sufficient to support the publication of the Bedrock Geological Map of Connecticut (Rodgers, 1985) and the Surficial Materials Map of Connecticut (Stone et al., 1992) was available and the field mapping component of the program had run its course on land. A list of published geologic maps for Connecticut (by quadrangle) is provided in the Data Catalogue.

Although much important work had been done in Long Island Sound (See Previous and Related Work Section), the transition from individual, periodic investigations to a coordinated, systematic mapping of the geology of the Long Island Sound basin had not yet occurred, and an overall geologic understanding of the basin was lacking. In the spring of 1980, the State Survey (under the direction of Dr. Hugo Thomas) began working with the U.S.G.S. to address this situation through a marine-oriented continuation of their long-standing geologic mapping "cooperative". Staff from the State Survey and the U.S.G.S. were assigned to the "co-op" which had two main goals: 1) completion of a systematic investigation of the geologic setting, geologic components, and geologic history of the Long Island Sound basin (Geologic Framework); and 2) development of an understanding of modern sedimentary processes and habitats in Long Island Sound (Modern Process).

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