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

Status Report on Interstate Correlation of Quaternary Units for North Carolina and Virginia's Joint Stratigraphic Studies of the Coastal Plain

Paper number: 22-1
Program: Technical Sessions
Time: 10:50 AM – 11:10 AM

Authors

Abstract

The North Carolina Geological Survey (NCGS) participated in a multi-year project with Virginia Energy (VA) to collect and exchange stratigraphic information for interstate correlation. Our purpose is to identify and core key localities in both states to establish new or revised stratotypes for Pliocene and Early Pleistocene map units that cover broad areas of the Coastal Plain.  Principal targets were updip units defined in Virginia—the Bacons Castle Formation and the informal Cold Harbor Formation.  New coring in VA was funded by STATEMAP.  In NC, collection of along-strike Geoprobe cores for correlation was funded by STATEMAP and EARTH MRI.  Graphic logs were prepared for each core to describe the depositional sequences and standardize the correlative units.  We provide here a status report on this research which remains ongoing.

To date, NCGS drilled 338 m (1,108.9 ft) of core at 28 boreholes in Virginia.  Most core localities occur at elevations of 38 to 74 m (125-245 ft) above mean sea level on terraces equivalent to NC’s Coharie and Sunderland terraces.  Previous mapping in VA indicates that the Bacons Castle surficially underlies terraces with surface elevations of ~ 35-51.8 m (115-170 ft)—the Sunderland and eastern part of the Coharie.  The informal Cold Harbor may occur at higher elevations surficially.  In NC, a well-constrained cross section through the Kenly scarp shows a clear disconnect between surficial coastal depositional sequences deposited west and east of this shoreline.  East is the Bacons Castle; but west is a thicker more complicated sand-rich depositional sequence (Cold Harbor? equivalent).   In VA, the stratigraphic relationships appear similar based on the current data set, but cores are widely spaced, and additional data is needed to construct an along-strike well-constrained cross section.

An hypothesis is that the Kenly shoreline marks a transition from normal to forced regression at a sea level  highstand of 52 m.  West of the Kenly are thick shoreline sands, in part, representing the highstand systems tract (HSST) associated with the Kenly shoreline.  East of the Kenly is the falling stage systems tract (FSST) (the Bacons Castle).  For NC, the HSST should be separated from the FSST as formal stratigraphic units.  Otherwise, the Bacons Castle becomes an internally complex and inconsistently defined unit.  Additional stratigraphic data is needed to support this interpretation.

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

doi: 10.1130/abs/2026SE-411755

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