Mollusk-isotope records of Plio-Pleistocene marine paleoclimate, U. S. Middle Atlantic Coastal Plain

Journal Article · Wed Aug 01 00:00:00 EDT 1990 · Palaois; (United States)

DOI:https://doi.org/10.2307/3514888· OSTI ID:5504776

Krantz, D E ^[1]

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1. Univ. of South Carolina, Columbia (USA)

Stable oxygen and carbon isotope profiles from fossil scallop shells provide detailed paleoenvironmental information for the Pliocene and early Pleistocene of the Middle Atlantic Coastal Plain. Scallop specimens were collected from strata which represent at least five major marine transgressions. Minimum and maximum paleotemperatures were calculated from the {delta}{sup 18}O ranges recorded in each shell profile, after adjusting for changes in seawater {delta}{sup 18}O related to changes in global ice volume. Paleotemperature ranges from each stratigraphic unit were compared with modern conditions on the shelves of the Middle and South Atlantic Bight, and with paleotemperatures estimated by Hazel (1971b, 1988) from the ostracode faunas. The mollusk-isotope records indicate that the marine climate of the Atlantic Shelf was mild temperate during the deposition of the Sunken Meadow Member of the Yorktown Formation in the early Pliocene. The climate became warm temperate during the middle and late Pliocene transgressions which deposited the Rushmere, Morgarts Beach and Moore House Members of the Yorktown Formation and the Chowan River Formation. During the deposition of the James City Formation in the early Pleistocene, temperatures returned to a mild temperate climate similar to that of the modern Virginia Bight shelf. The character of the isotope profiles indicates that hydrographic conditions were generally stable and similar to those of the modern Middle Atlantic Bight. The {delta}{sup 13}C profiles of most of the shells show trends suggestive of spring phytoplankton blooms and summer water-column stratification. Anomalies in several profiles are interpreted as reduced salinity events, probably related to river discharge, which most commonly occur in the spring. There is no convincing evidence in the shell profiles for upwelling.

• OSTI ID: 5504776
• Journal Information: Palaois; (United States), Vol. 5:4
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
MOLLUSCS
ISOTOPE RATIO
PLEISTOCENE EPOCH
PALEOCLIMATOLOGY
PLIOCENE EPOCH
CARBON 13
CONTINENTAL SHELF
DEPOSITION
EAST COAST
FOSSILS
GEOLOGIC FORMATIONS
GEOLOGIC HISTORY
GEOLOGIC STRATA
MID-ATLANTIC BIGHT
OXYGEN 18
PALEOTEMPERATURE
SALINITY
SAMPLING
SEA LEVEL
SEAWATER
SEDIMENTARY ROCKS
STRATIGRAPHY
USA
ANIMALS
AQUATIC ORGANISMS
ATLANTIC OCEAN
CARBON ISOTOPES
CENOZOIC ERA
CONTINENTAL MARGIN
DEVELOPED COUNTRIES
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
GEOLOGIC AGES
GEOLOGIC STRUCTURES
GEOLOGY
HYDROGEN COMPOUNDS
INVERTEBRATES
ISOTOPES
LEVELS
LIGHT NUCLEI
NORTH AMERICA
NUCLEI
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
PALEONTOLOGY
QUATERNARY PERIOD
ROCKS
SEAS
STABLE ISOTOPES
SURFACE WATERS
TERTIARY PERIOD
WATER
580000* - Geosciences