Quaternary sedimentation in a tide-dominated estuary, northern New England

Conference · Mon Mar 01 04:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5579304

Ward, L G ^[1]

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1. Univ. of New Hampshire, Durham, NH (United States)

Northern New England is characterized by rocky shorelines frequently interrupted by linear embayments or estuaries. In contrast to more commonly studied coastal plain estuaries further south, these embayments often have relatively limited fluvial sediment supply, are affected by ice, and are strongly influenced by bedrock geology. High resolution subbottom seismics, sidescan sonar, surficial sediment sampling and gravity coring were conducted in the Piscataqua River Estuary, New Hampshire, in order to describe the sedimentary environments. The study represents an initial step in determining the Quaternary history and developing a depositional modal of a transgressive, tide-dominated, bedrock influenced system, which is typical of cold, ice impacted estuarine environments of northern New England. The Piscataqua River Estuary is undergoing a relatively slow submergence (approximately 1.5--2.0 mm/yr) due largely to eustatic sea level rise. The upper regions of the estuary have large, fine-grained shoals, extensive tidal flats, and salt marsh deposits. Radionuclide dating (Pb-210 and Cs-137) of cores from these marshes indicates accretion rates range from 0.26 to 1.42 cm/yr, which exceed local sea level rise. By contrast, the lower Estuary which has a limited sediment supply has extensive bedrock outcrops which are found along the shores and subtidally. The dominant depositional environments include muddy intertidal flats, muddy to sandy subtidal flats, and sandy to gravelly channels. The most common surficial sediments types are moderately to poorly sorted muddy sands and sandy gravel deposits. Gravity coring along the flanks of the Estuary indicate that fine-grained Holocene sediments, typically less than a few meters thick, are underlain by marine sandy muds associated with the Presumpscot Formation, tills, or bedrock.

• OSTI ID: 5579304
• Report Number(s): CONF-9303211--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 25:2
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
AGE ESTIMATION
AQUATIC ECOSYSTEMS
CENOZOIC ERA
COASTAL REGIONS
DEPOSITION
DEVELOPED COUNTRIES
ECOSYSTEMS
EROSION
ESTUARIES
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC HISTORY
GEOLOGY
GEOMORPHOLOGY
GEOPHYSICAL SURVEYS
ISOTOPE DATING
LEVELS
MARSHES
NEW HAMPSHIRE
NORTH AMERICA
QUATERNARY PERIOD
SAMPLING
SEA LEVEL
SEDIMENTS
SEISMIC SURVEYS
SHORES
STRATIGRAPHY
SURFACE WATERS
SURVEYS
USA
WETLANDS