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Seth D. Ackerman

Publications and source records attributed to Seth D. Ackerman.

27 records · Page 2Linked to original sources
USGS2008

Sea-floor character and sedimentary processes in the vicinity of Woods Hole, Massachusetts

Continuous-coverage multibeam bathymetric models and sidescan-sonar imagery have been verified with high-resolution seismic-reflection profiles, sediment sampling, and bottom photography. Together these data layers provide detailed base maps that yield topographic, compositional, and environmental perspectives of the sea floor in the vicinity of Woods Hole, an important harbor and major passage between the Elizabeth Islands and Cape Cod, Massachusetts. Tidally dominated high-energy environments within Woods Hole have prevented deposition of Holocene marine sediments, exposed underlying glacial drift of the Buzzards Bay moraine, and winnowed finer grained sediments, leaving lag deposits of boulders and gravel. These conditions have also enlarged and preserved depressions in the moraine surface that were originally kettle holes and formed ebb-tidal deltas at the entrances to passages. Fields of transverse and barchanoid sand waves dominate across the southern part of the study area in Vineyard Sound, where benthic environments are characterized by processes associated with coarse-bedload transport. Transverse sand waves dominate near shoals where sediment supply is greater and have asymmetries that indicate that the shoals are shaped and maintained by clockwise gyres of net sediment transport. Barchanoid sand waves, which are most common where Holocene sediments are thinner, commonly align into elongate fields that have smaller isolated waves concentrated at the eastern ends and that progressively widen and have waveforms that increase in amplitude, wavelength, and complexity westward. The northern, protected parts of the Little and Inner Harbors are characterized by muddy sediment and processes associated with deposition. A pockmark field in Little Harbor and the muddy, organic-rich sediments that form a scarp along the edge of Parker Flat are evidence for the presence of submerged marsh deposits formed during the Holocene rise in sea level.

Massachusetts↗
USGS2008

Enhanced Sidescan-Sonar Imagery Offshore of Southeastern Massachusetts

The U.S. Geological Survey (USGS), National Oceanic and Atmospheric Administration (NOAA), and Massachusetts Office of Coastal Zone Management (CZM) have been working cooperatively to map and study the coastal sea floor. The sidescan-sonar imagery collected during NOAA hydrographic surveys has been included as part of these studies. However, the original sonar imagery contains tonal artifacts from environmental noise (for example, sea state), equipment settings (for example, power and gain changes), and processing (for example, inaccurate cross-track and line-to-line normalization), which impart a quilt-like patchwork appearance to the mosaics. These artifacts can obscure the normalized backscatter properties of the sea floor. To address this issue, sidescan-sonar imagery from surveys H11076 and H11079 offshore of southeastern Massachusetts was enhanced by matching backscatter tones of adjacent sidescan-sonar lines. These mosaics provide continuous grayscale perspectives of the backscatter, more accurately reveal the sea-floor geologic trends, and minimize the environment-, acquisition-, and processing-related noise.

Open-File Report↗
USGS2007

Sea-floor character and sedimentary processes of Great Round Shoal Channel, offshore Massachusetts

The imagery, interpretive data layers, and data presented herein were derived from multibeam echo-sounder and sidescan-sonar data collected in the vicinity of Great Round Shoal Channel, the main passage through shoals located at the eastern entrance to Nantucket Sound, Massachusetts, and from the stations occupied to verify these acoustic data (fig. 1). Basic data layers show sea-floor topography, sun-illuminated shaded relief, and backscatter intensity; interpretive layers show the distributions of surficial sediment, sedimentary environments, and sea-floor features. Presented verification data include sediment grain-size analyses and a gallery of still photographs of the seabed. The multibeam and sidescan data, which together cover an approximately 39.9-km² area of sea floor, were collected during National Oceanic and Atmospheric Administration (NOAA) hydrographic survey H11079 (fig. 1). Although originally collected for charting purposes, these data provide a fundamental framework for research and management activities along this part of the Massachusetts coastline (Noji and others, 2004), show the composition and terrain of the seabed, and provide information on sediment transport and benthic habitat. This publication is the third in a series of U.S. Geological Survey (USGS) digital reports describing the sea-floor geology around Cape Cod. The first focused on the area off the eastern shore of the outer Cape (Poppe and others, 2006); the second on a passage through the Elizabeth Islands (Poppe and others, 2007).

Massachusetts↗
USGS2006

Geological interpretation of bathymetric and backscatter imagery of the sea floor off eastern Cape Cod, Massachusetts

The imagery, interpretive data layers, and data presented herein were derived from multibeam echo-sounder data collected off Eastern Cape Cod, Massachusetts, and from the stations occupied to verify these acoustic data. The basic data layers show sea-floor topography, sun-illuminated shaded relief, and backscatter intensity; interpretive layers show the distributions of surficial sediment and sedimentary environments. Presented verification data include new and historical sediment grain-size analyses and a gallery of still photographs of the seabed. The multibeam data, which cover a narrow band of the sea floor extending from Provincetown around the northern tip of Cape Cod and south southeastward to off Monomoy Island, were collected during transits between concurrent mapping projects in the Stellwagen Bank National Marine Sanctuary (Valentine and others, 2001; Butman and others, 2004; and Valentine, 2005) and Great South Channel (Valentine and others, 2003a, b, c, d). Although originally collected to maximize the use of time aboard ship, these data provide a fundamental framework for research and management activities in this part of the Gulf of Maine (Noji and others, 2004), show the composition and terrain of the seabed, and provide information on sediment transport and benthic habitat. These data and interpretations also support ongoing modeling studies of the lower Cape’s aquifer system (Masterson, 2004) and of erosional hotspots along the Cape Cod National Seashore (List and others, 2006).

Massachusetts↗
USGS2006

Interpolation of reconnaissance multibeam bathymetry from north-central Long Island Sound

Introduction The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration (NOAA) and the Connecticut Department of Environmental Protection (CT DEP), has produced detailed maps of the sea floor in Long Island Sound, a major East Coast estuary surrounded by the most densely populated region of the United States (fig. 1). The current phase of this cooperative research program is directed toward studies of sea-floor topography and its effect on the distributions of sedimentary environments and benthic communities. Because anthropogenic wastes, toxic chemicals, and changes in land-use patterns resulting from residential, commercial, and recreational development have stressed the environment of the Sound, causing degradation and potential loss of benthic habitats (Koppelman and others, 1976; Long Island Sound Study, 1994), detailed maps of the sea floor are needed to help evaluate the extent of adverse impacts and to help manage resources wisely in the future.

Connecticut, New York↗
USGS2006

High-resolution geologic mapping of the inner continental shelf: Boston Harbor and approaches, Massachusetts

This report presents the surficial geologic framework data and information for the sea floor of Boston Harbor and Approaches, Massachusetts (fig. 1.1). This mapping was conducted as part of a cooperative program between the U.S. Geological Survey (USGS), the Massachusetts Office of Coastal Zone Management (CZM), and the National Oceanic and Atmospheric Administration (NOAA). The primary objective of this project was to provide sea floor geologic information and maps of Boston Harbor to aid resource management, scientific research, industry and the public. A secondary objective was to test the feasibility of using NOAA hydrographic survey data, normally collected to update navigation charts, to create maps of the sea floor suitable for geologic and habitat interpretations. Defining sea-floor geology is the first steps toward managing ocean resources and assessing environmental changes due to natural or human activity. The geophysical data for these maps were collected as part of hydrographic surveys carried out by NOAA in 2000 and 2001 (fig. 1.2). Bottom photographs, video, and samples of the sediments were collected in September 2004 to help in the interpretation of the geophysical data. Included in this report are high-resolution maps of the sea floor, at a scale of 1:25,000; the data used to create these maps in Geographic Information Systems (GIS) format; a GIS project; and a gallery of photographs of the sea floor. Companion maps of sea floor to the north Boston Harbor and Approaches are presented by Barnhardt and others (2006) and to the east by Butman and others (2003a,b,c). See Butman and others (2004) for a map of Massachusetts Bay at a scale of 1:125,000. The sections of this report are listed in the navigation bar along the left-hand margin of this page. Section 1 (this section) introduces the report. Section 2 presents the large-format map sheets. Section 3 describes data collection, processing, and analysis. Section 4 summarizes the geologic history of the region and discusses geomorphic and anthropogenic features within the study area. Section 4 also provides references that contain additional information about the region. Appendix 1 provides GIS layers of all the data collected in this study, Appendix 2 contains the grain size textural analyses of sediment samples, and Appendix 3 contains bottom photographs of the sea floor in JPG format.

Massaachusetts↗
USGS2006

Geologic interpretation and multibeam bathymetry of the sea floor in southeastern Long Island Sound

Digital terrain models (DTMs) produced from multibeam echosounder (MBES) bathymetric data provide valuable base maps for marine geological interpretations (e.g. Todd and others, 1999; Mosher and Thomson, 2002; ten Brink and others, 2004; Poppe and others, 2006a,b). These maps help define the geological variability of the sea floor (one of the primary controls of benthic habitat diversity); improve our understanding of the processes that control the distribution and transport of bottom sediments, the distribution of benthic habitats and associated infaunal community structures; and provide a detailed framework for future research, monitoring, and management activities. The bathymetric survey interpreted herein (National Oceanic and Atmospheric Administration (NOAA) survey H11255) covers roughly 95 km? of sea floor in southeastern Long Island Sound (fig. 1). This bathymetry has been examined in relation to seismic reflection data collected concurrently, as well as archived seismic profiles acquired as part of a long-standing geologic mapping partnership between the State of Connecticut and the U.S. Geological Survey (USGS). The objective of this work was to use these geophysical data sets to interpret geomorphological attributes of the sea floor in terms of the Quaternary geologic history and modern sedimentary processes within Long Island Sound.

Open-File Report↗
USGS2003

Texture, Carbonate Content, and Preliminary Maps of Surficial Sediments of the Flower Garden Banks Area, Northwestern Gulf of Mexico Outer Shelf

The purpose of this report is to release texture and carbonate content analyses of 107 seafloor sediments collected within and near the East and West Flower Garden Banks areas of the Sanctuary and to show relationships between these data and existing bathymetric data. The sediment data, in conjunction with previously collected geological, geophysical and biological data were used to construct a reconnaissance-scale map of the distribution of seafloor sediment types. This map will be useful for resource managers and can be used, with additional data, as a basis for future habitat mapping.

Open-File Report↗