Department or Program



Late Holocene climate fluctuations resulted in pronounced coastal change across the North Atlantic. The transition between the stable Medieval Warm Period and the stormy Little Ice Age was associated with an increased north-south thermal gradient that led to a southward displacement of the polar atmospheric front and polar waters. The increased frequency and intensity of storms during the LIA resulted in inland sand transgressions that displaced communities across Europe and altered coastlines in the process. A case study of this coastal change can be observed in the southern Shetland Islands, where extensive, thick deposits of sand stretch far inland. Within these sands are the buried remains of the township of Broo, which was abandoned in the midst of total inundation in the mid-18th century (Bigelow et al. 2005). The nearby Loch of Brow contains a distinctive, fine sand unit that has been hypothesized to be a result of the sand invasion event(s) that buried the township of Broo. Also within the study area are the Bay of Scousburgh and the Loch of Spiggie. 17th century maps show an inlet connecting the Loch of Spiggie to the ocean through the Bay of Scousburgh, but presently there is a low-lying land bridge separating the two. It has been hypothesized that the land bridge, as well as a sand unit found in the Loch of Spiggie, were created during a period of intense storminess within the LIA. In order to test the hypotheses presented, sand samples were collected from around the study area and subjected to x-ray diffraction, grain size analysis, and grain surface morphology. XRD results established a mineralogic relationship between the Loch of Spiggie and the Bay of Scousburgh. These sites shared peaks in their diffractions that were missing in the Quendale sites and the Loch of Brow, simultaneously establishing a potential relationship between these sites as well. A trend of decreasing grain size and increasing sorting was observed between the Bay of Quendale and the Loch of Brow, suggesting a fining of sediment through aeolian transportation. This trend was not observed between the Bay of Scousburgh and the Loch of Spiggie, suggesting a more powerful transport mechanism. The grain surface morphology observations revealed that the sediment in the Loch of Brow had been in aeolian transportation for a long time before being subjected to a more forceful storm that carried it to its current location. At the Broo archaeological site, grains underneath thin organic horizons exhibited silica dissolution and precipitation, suggesting that the inundation of the site occurred in stages, with a strong storm depositing sand and a subsequent stable period enabling the growth of surface vegetation. Grains from the Loch of Spiggie showed textures associated with powerful subaqueous transportation. Together with the grain size analysis results, the sand unit in the loch appears to have been deposited as washover during a high-magnitude storm. This same sand invasion event appears to have created the land bridge that currently separates the Loch of Spiggie from the Bay of Scousburgh.

Level of Access

Open Access

First Advisor

Michael Retelle

Date of Graduation


Degree Name

Bachelor of Science

Number of Pages


Open Access

Available to all.