22 Interstate Stratigraphic Correlation: A Practical Geology Session

Primarily a hands-on display of core and samples with posters, and talks, to facilitate interstate correlation. Concepts covered are related to interstate correlation problems in stratigraphy—mapping, source rocks for REE minerals, geochronology, and regolith.

Tuesday, 10 March 2026
10:30 AM - 12:00 PM
RCC, 103

Refining Late Cenozoic Molluscan Biostratigraphy in the Carolinas and Virginia

Paper number: 22-3
Program: Technical Sessions
Time: 11:30 AM – 11:50 AM

Authors

Abstract

                Variations in sea level, local erosion patterns, and local tectonic activity have created a complex patchwork of fossiliferous deposits across the coastal plain. Many biostratigraphically distinctive units have similar lithology and have been confused in the past. Intensive sampling of molluscan faunas and documentation of unconformities enables recognition of multiple transgressions in the Pliocene and lower Pleistocene. We used calcareous nannofossils and intensive sampling of mollusk faunas to provide biostratigraphic zonation, along with updating published correlations in light of recent refinements to timescales and marker zonations.

                Stratigraphic nomenclature for the region must deal with several legacy names and determine what to treat as lithostratigraphic, biostratigraphic, or allostratigraphic units. Both the Moore House Member of the Yorktown Formation and the Bear Bluff Formation have been applied to lithologically and stratigraphically disparate deposits.

                Nine faunally distinct transgressions can be recognized in the Pliocene and two more in the Gelasian (former upper Pliocene, now transferred to the Pleistocene). Sites with the best aragonitic preservation may have over 800 species of mollusks. Scallops are especially useful index species, combining durable calcite shells with often easily distinguished morphologies. Based on these data, we revise correlations for the Yorktown, Wabasso, Duplin, Chowan River, Bear Bluff, James City, and Waccamaw Formations, the Raysor Marl, and the Goose Creek Limestone. In general, the dates we determine are somewhat older than many current models, with the Rushmere Member in the Zanclean, Chowan River in the upper Piacenzian, and Waccamaw in the Gelasian. The mid-Piacenzian warm period best corresponds with the uppermost Yorktown and Duplin Formations. 

Geological Society of America Abstracts with Programs. Vol. 58, No. 1

doi: 10.1130/abs/2026SE-411619

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