Excavation
Date 29 February 2016 - 4 March 2016
Event ID 1022377
Category Recording
Type Excavation
Permalink http://canmore.org.uk/event/1022377
NO 70460 97790 Work was undertaken, 29 February – 4 March 2016, and began with a full topographical survey of the island that used DGPS to capture 2720 individual points with associated height data. A digital terrain
model was produced with this data that also surveyed the surviving extant medieval castle masonry. The results of the topographical survey have provided clearer insight into the former level of the loch and its relationship to the island which appears to have sunk by as much as 3m. The survey also demonstrated the level of survival of the upstanding medieval remains extant on the site which were first mapped by Burnett in 1850. The outline of the medieval tower house can still be clearly traced across the eastern half of the islet, but is less clear or absent along what Burnett sees as the western wall.
Excavation of a single 2 x 3m trench was undertaken that tested the nature of the surviving archaeology and obtained material for C14 dating. The excavation provided unambiguous evidence for the artificiality of the island, and also demonstrated surviving laid masonry below the former level of the loch capping the organic matrix of the artificial island. The excavation has characterised the preservation of the organic component of the site which has substantially deteriorated since the 1850 draining of
the loch and excavation of the crannog by Burnett. The main organic matrix of the crannog has been reduced to a deteriorated black mass with frequent bark fragment inclusions. A single highly degraded timber fragment was identified.
Two radiocarbon dates from the site have placed activity around the 1st–2nd centuries AD as well as in the 9th–10th centuries AD. The 1910±30 BP (Poz-83364) date came from small charcoal fragments within context (108), interpreted as an erosional layer sitting near the former surface of the water. This sat above the assumed medieval period laid stone capping [106] of the main organic mound (103). Within (108) a 15mm diameter fragment of mortar was found, and was initially thought to represent redeposited rubble material from the deterioration of the medieval tower house. The most likely explanation in light of the 1st-2nd-century AD charcoal date is that (108) is an erosional deposit, where the charcoal sampled was eroded out of the crannog mound and redeposited alongside the obviously medieval mortar.
The second date, 1095±30 BP (Poz-83362), came from context (103) the main core of the organic anthropogenic mound. This context was homogenous throughout, so samples were taken through the profile. This C14 date comes from a sample from the upper part of the profile, just below the laid stone capping [103].
Archive: NRHE and Archaeology Service for Aberdeen City, Aberdeenshire, Angus and Moray
Funder: Society of Antiquaries of Scotland, Archaeology Service for Aberdeen City, Aberdeenshire, Angus and Moray
Michael J Stratigos – University of Aberdeen
(Source: DES)
