skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

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

Abstract

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 profilesmore » 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.« less

Authors:
 [1]
  1. (Univ. of South Carolina, Columbia (USA))
Publication Date:
OSTI Identifier:
5504776
Resource Type:
Journal Article
Resource Relation:
Journal Name: Palaois; (United States); Journal Volume: 5:4
Country of Publication:
United States
Language:
English
Subject:
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

Citation Formats

Krantz, D.E.. Mollusk-isotope records of Plio-Pleistocene marine paleoclimate, U. S. Middle Atlantic Coastal Plain. United States: N. p., 1990. Web. doi:10.2307/3514888.
Krantz, D.E.. Mollusk-isotope records of Plio-Pleistocene marine paleoclimate, U. S. Middle Atlantic Coastal Plain. United States. doi:10.2307/3514888.
Krantz, D.E.. Wed . "Mollusk-isotope records of Plio-Pleistocene marine paleoclimate, U. S. Middle Atlantic Coastal Plain". United States. doi:10.2307/3514888.
@article{osti_5504776,
title = {Mollusk-isotope records of Plio-Pleistocene marine paleoclimate, U. S. Middle Atlantic Coastal Plain},
author = {Krantz, D.E.},
abstractNote = {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.},
doi = {10.2307/3514888},
journal = {Palaois; (United States)},
number = ,
volume = 5:4,
place = {United States},
year = {Wed Aug 01 00:00:00 EDT 1990},
month = {Wed Aug 01 00:00:00 EDT 1990}
}
  • The middle Pliocene, {approximately}3.5-2.5 Ma, was a period of global warmth preceding the growth of major Northern Hemisphere ice sheets. The authors report on eustatic sea level for the middle Pliocene based on microspaleontologic study of marine deposits of the Duplin Formation of South Carolina and North Carolina. The Duplin was deposited during a middle Pliocene marine transgression that formed the Orangeburg scarp, a prominent wave-cut geomorphic paleoshoreline of the southeastern U.S. Atlantic Coastal Plain. They concluded that (1) the scarp in South Carolina was formed mostly during the middle Pliocene (3.5-3.0 Ma), (2) eustatic sea level was about 35more » {plus minus} 18 m higher than modern sea level (the scarp has been uplifted about 50-65 m since the middle Pliocene), and (3) ocean-water temperatures along eastern North America were warmer when the scarp was formed that they are at present.« less
  • Stable oxygen and carbon isotopes of pedogenic carbonate provide a detailed record of paleoclimatic changes from late Pliocene through early Pleistocene in the Rio Grande rift of south-central New Mexico. 30 calcic paleosols were sampled at three stratigraphic sections of the fluvial lithofacies of the Camp Rice Formation, and one calcic paleosol was sampled from fluvial sediment inset against the Camp Rice Formation. Paleosols commonly consist of an argillic B horizon (Bt) overlying a calcic (Bk) or petrocalcic (Km) horizon. The majority of paleosols consist of state II morphology calcic horizons, although one stage V horizon and five stage IIImore » horizons were also sampled. Reversal magnetostratigraphy at all four sample sites bracket the age of the paleosol-bearing strata between 2.4 and 0.7 Ma and allow estimates of the absolute age of individual paleosols. Three paleoclimatic stages are indicated by the carbon and oxygen isotopic data from south-central New Mexico. The initial stage, from 3.1 to 2.5 Ma, was characterized by the overall lowest values of [partial derivative][sup 18]O and [partial derivative][sup 13]C and by an increase in values with decreasing age, suggesting high effective moisture and abundant winter precipitation, which decreased through time, and/or relatively low temperature, which increased through time. The second stage (2.5-1.4 Ma) displays an increase in [partial derivative][sup 18]O with decreasing age but no significant change in [partial derivative][sup 13]C with time, suggesting that the effective moisture was nearly constant, but that the temperature and/or summer precipitation may have increased through time. The final stage (1.4-0.7 Ma) shows an overall increase in both [partial derivative][sup 18]P and [partial derivative][sup 13]C with decreasing age corresponding to less effective moisture, higher temperature, and/or greater summer precipitation through time. 56 refs., 6 figs., 2 tabs.« less
  • Paleowaters from the Floridan aquifer system in the southeastern Atlantic coastal plain have higher D/H and [sup 18]O/[sup 16]O ratios than local Holocene groundwater. Maximum [delta][sup 18]O enrichments in groundwater having adjusted radiocarbon ages of 20,000 to 26,000 years are 0.7 to 2.3 per mil. The trend in isotopic enrichment in paleowaters is the reverse of that normally observed in continental glacial age groundwater. Dissolved nitrogen and argon concentrations indicate, however, that the average recharge temperature was 5.3[degrees]C cooler than that today. The data indicate cool conditions in the southeast Atlantic coastal plain during the last glacial maximum, with rechargemore » limited primarily to late summer tropical cyclones and hurricanes.« less
  • The interpretation of the regional aminostratigraphy of Coastal Plain Quaternary units from North and South Carolina is potentially affected by sampling biases, variable preservation of coastal records, reoccupation of coastal environments by multiple transgressions, geochemical alteration of samples, variable thermal histories of specific samples, and intergeneric and interlaboratory differences in analytical results.Two primary models for the correlation of emergent Coastal Plain units diverge significantly in southeastern North Carolina. New data from fresh exposure (1990--1991) at emergent sites between Wilmington, NC and Charleston, SC, from previous onshore collections in this region, and from submergent samples between Cape Lookout, NC and Capemore » Romain, SC provide insight into the nature of these correlation issues. Although sampling of the area is not uniform, these results fill a major gap between regions of previous aminostratigraphy study. Inferred early-to-middle Pleistocene aminozones dominate the emergent coastal region between Cape Lookout and Romain, and late Pleistocene aminozones in this area are represented by subsurface samples beneath barrier islands or in shallow inner shelf cores, but have not been found onshore. A map view of the distribution of aminozones along the coast between northeastern NC and central SC mimics that of pre-Quaternary units that thin or disappear over the axis of the Cape Fear Arch, suggesting that the sampled Quaternary record reflects the combination of processes responsible for the preservation of the pre-Quaternary record. This perspective should provide a model for resolution of various geochronological controversies that have arisen because of limited stratigraphic or geochemical data.« less