5 Undergraduate Research Poster Session I

Friday, 28 March 2025
8:30 AM - 5:30 PM
North Great Hall

PALYNOLOGICAL (POLLEN) INVESTIGATION OF AN ANCIENT SOIL HORIZON ON THE EASTERN SHORE, VA: IMPLICATIONS FOR ENVIRONMENTAL CHANGE

Paper number: 5-33
Program: Theme Sessions
Time: 8:30 AM – 5:30 PM

Authors

Abstract

This research investigates ancient soil horizons, or paleosols, at the Savage Neck Dunes Natural Area Preserve on Virginia's Eastern Shore, a region within the Chesapeake Bay. These soils, recently exposed by erosion, contain critical records of past vegetation and climatic conditions. The study focuses on palynology—the analysis of fossil pollen—and its use in reconstructing paleoecological and paleoclimatic changes from the late Pleistocene to the Holocene. Fieldwork involved GPS mapping of the exposed ghost forest, which consists of 117 ancient trees, and collecting core samples from 13 sites across the paleosol and underlying peat/underclay layers. Aerial imagery was also used to document the extent of soil exposures, emphasizing the impact of storm-driven erosion, including damage caused by Tropical Storm Elsa.

In the laboratory, samples were disaggregated with distilled water and Calgon solution, sieved to remove larger clasts, and processed using a centrifuge with lithium heteropolytungstate (LST) to separate grains by density. Floating grains, including pollen, were decanted, filtered, and prepared for microscopic analysis. Using a Nikon Eclipse light microscope, pollen grains were identified and categorized. Preliminary results indicate a distinct climatic transition, with arboreal pollen dominant in the peat and underclay, and non-arboreal pollen, such as grass types, prevalent in the paleosol. This shift points to warming conditions and environmental changes during the soil's formation.

The research demonstrates the potential of ancient soils to inform understanding of past climates and environments in the mid-Atlantic region. By combining detailed field methods with laboratory analyses, this study provides insights into historical vegetation shifts and highlights the importance of preserving these unique paleosol records amidst ongoing coastal erosion. Future steps include radiocarbon dating of organic remains to refine the timeline of environmental changes recorded in the paleosol layers.

Geological Society of America Abstracts with Programs. Vol. 57, No. 3

doi: 10.1130/abs/2025NE-409035

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