Field Visit

Date 19 September 2016

Event ID 1040840

Category Recording

Type Field Visit

Permalink http://canmore.org.uk/event/1040840

HU 3953 4753 (HU34NE 1) The Shetland Islets survey intended to examine a range of islet sites including two brochs, a dun and a castle in Shetland. The aim was to gather survey data concerning the nature of the submerged portions of the islets to enable comparison to mainland Scottish crannogs. Castle Holm is located in the brackish, slightly tidal, Strom Loch, Whiteness, and was surveyed on 19 September 2016. The islet is oval shaped extending 20 x 7m above water and 34 x 24m below water. There is a substantial upstanding portion of the castle wall which stands as high 2.2m and is 1.2m thick at it widest point. There is a causeway out to the islet from the nearest shore made up of boulders 0.3–1.0m in diameter. The islet underwater is similarly composed of medium sized boulders, which are not natural accumulations of material. Only excavation would be able to tell whether these boulders were laid down to create the island or are material that has tumbled down from contexts higher up. It was suspected that the medieval castle might be sitting on

an earlier monumental roundhouse site. No evidence for this was found during the survey, but it cannot be ruled out at this stage either.

It was also noted that substantial erosion appears to be taking place on the upstanding masonry. Discussion with the local landowner and a nearby resident revealed that the structure has lost at least 0.5m in height over the past few decades. Photogrammetric survey of the upstanding masonry was carried out to provide a baseline for future quantification of the rate of degradation.

Archive: Shetland Amenity Trust (intended)

Funder: Shetland Amenity Trust

Michael J Stratigos – University of Aberdeen

(Source: DES, Volume 18)