Knowing the timing of dune activation and stabilization is crucial for
correlation of dune phases to possible triggering events, such as arrival of European
settlers, opening and closing of inlets and the widespread cooling of the Little Ice Age.
Although IR-OSL analysis is not yet complete, the following preliminary conclusions about
possible causal factors have been determined:
Regional versus local factors:
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Older phases of dune activity on the two southern dunes are
most likely caused by local factors because older dunes are limited to the southern
portion of the region (see blue dots, Jockeys Ridge, and Run Hill on location map below). |
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The current phase of activity on all four dunes is most
likely caused by a combination of local and regional effects because the coast is not
composed entirely of active dunes. |
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Sediment source:
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Inlet opening and closing (Fisher, 1962; see figure for
inlet locations) could have provided a local sediment source for all four study dunes. |
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The Albemarle stream paleochannel (see figure) that formed
during the last glacial advance (sea-level lowstand; Riggs and others, 1992) is the likely
sediment source for the two larger, more complex southern dunes.
The concentration of dunes shown in the area near Jockeys Ridge and Run Hill suggests that
more sediment was available to this location compared to other dune locations along the
coast. The Albemarle paleochannel would have provided this large volume of sand. |
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