Archaeological Evaluation

Date 11 June 2019

Event ID 1106351

Category Recording

Type Archaeological Evaluation

Permalink http://canmore.org.uk/event/1106351

NR 86770 68730 A programme of buildings and materials analysis was undertaken at Tarbert Castle, 11 June 2019, in conjunction with a community excavation.

Buildings analysis during the first period of investigation revealed that the cross-wall dividing the inner and outer enclosures had been inserted, within a pre-existing curtain wall which probably encircles the whole site. On plan and in elevation the curtain wall is continuous and clearly abutted by both ends of the mortar-coated cross-wall. Although difficult to positively demonstrate from the fragmentary upstanding remains, it is likely this cross-wall is coeval with the buildings ranged around the inner enclosure.

Both main constructional phases have been constructed with lime-bonded masonry, visible in extensive core, bedding and coating contexts, with a mortar floor also revealed by excavation within a range of the inner enclosure. Both main phases are bound with wood-fired limestone-lime mortars, tempered with aggregates from foreshore contexts. No multiperiodicity was noted in the mortars associated with either phase, although some contrasts in mortar compositions and condition between phases was apparent. In particular, the mortar binding and coating the cross-wall mortar appears to be included with a higher concentration of large O. edulis (oyster) shell fragments and retains much greater coherence (in closely adjacent contexts) than the surrounding curtain. This contrast in surviving coherence is consistent with their relative dates and might suggest these constructional events are separated by significant period of time, although that remains to be demonstrated and other causes are possible.

Samples of various building materials were removed over two periods of work for further lab-based analysis. The sample assemblage includes mortar and mortar-entrapped relict fuel fragments from in situ contexts associated with both main constructional phases, as well as a sandstone fragment from the curtain wall and a loose limestone kiln relict sample from the inner enclosure.

Archive: NRHE (intended)

Funder: Historic Environment Scotland, University of Stirling and Tarbert Castle Trust

Mark Thacker - University of Stirling

(Source: DES Vol 20)