Run Hill GPR Data
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| Run Hill dune is migrating over a large, stabilized dunefield underlying Nags Head Woods. The dashed line shows the predicted continuation of the Nags Head Woods precipitation ridge (leading edge of dunefield that is migrating onto a vegetated area) under Run Hill. The Run Hill E-W GPR line (below) clearly delineates this buried ridge. |
| GPR enabled us to predict where we might find the soil exposed at the
surface at position 15-west. The portion of the paleosol west of the exposure at position
105 was assumed to be lost to erosion because of the truncation of this horizon by an
eastward migrating superimposed dune at position 55-95-east (highlighted in yellow). GPR
delineated the subsurface geometry of the paleosol, leading us to a new soil exposure and
sample site in which a stump was found in place, rooted in the paleosol. The buried high ridge located approximately from position 60-west to position 65-east has a steeply westward dipping slope and strata. Its position on the dune along with the steep westward strata indicate that this feature is a continuation of the precipitation ridge of the Nags Head Woods dunefield (see infrared aerial photo above). |
| Older dunes (below buried soil) have a southerly dipping component to foreset strata, which contrasts with the dip angle of the precipitation ridge strata shown in the E-W GPR line above. Younger dune foresets with a steep southerly dip drape the older dune. A package of strata within an eastward-migrating superimposed dune is clearly shown between position 225 and position 265 (highlighted yellow). |