Onshore-Offshore Surficial Geologic Map of the Newburyport East and Northern Half of the Ipswich Quadrangles, Massachusetts

This geologic map shows the distribution of surficial subaerial and subaqueous materials in the Newburyport East and northern half of the Ipswich 7.5' quadrangles (northeast Massachusetts) and the area of the Gulf of Maine immediately offshore, to an approximate depth of 80 m below modern mean sea level (MSL). This map was compiled from the onshore surficial geologic map of Stone et al. (2006) and the offshore surficial mapping of Barnhardt et al. (2009), and includes newly mapped shallow offshore geologic features. Onshore and offshore units are continuous across the shallow- water zone (0-20 m below MSL). The definition of map units is based on lithologic characteristics (grain size, mineralogy and structure), stratigraphic relationships and relative ages, and sedimentologic processes. The map describes the evolution of the surficial geology in terms of the sediment sources, transportation mechanisms, and depositional, post-depositional and modern processes that have acted on the late Quaternary sediments that compose these units. Cross sections are derived from subsurface data compiled from the literature and collected as part of this study. This maps supersedes MGS OFR 2011-01

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