Mortar Analysis

Event ID 1106526

Category Recording

Type Mortar Analysis

Permalink http://canmore.org.uk/event/1106526

NJ 1892 6725 A programme of landscape, buildings and materials analysis is being carried out at Duffus Castle within the framework of this project. Buildings analysis of the upstanding complex at Duffus Castle recognised that, despite multiple episodes of masonry consolidation, constructional mortar materials of consistent character remain exposed in several continuous core, bedding and coating contexts. In situ analysis suggested that the constructional mortars associated with all upstanding structures could be characterised as wood-fired limestone-limes, and so a programme of sampling was undertaken to further investigate the archaeological and palaeoenvironmental potential of these materials. The sample assemblage from the site included 20 fuel inclusions, 3 mortar fragments (from the W keep, N curtain wall, and N range), and 1 relict limestone clast.

Materials analysis of the Duffus Castle assemblage included microscopic analysis of all mortar and limestone samples, and comparative analysis of various rock samples collected from local outcrops. These analyses demonstrated that the lime source in all sampled constructional phases displays a heterogenous but generally microcrystalline/mudstone texture, consistent with samples removed and collected from a nearby Stotfield Cherty Rock Formation limestone outcrop at Inverugie. The sample removed from the N range displayed a temper profile which clearly contrasts with the materials removed from the W keep and N curtain/kitchen, and this needs further investigation through buildings analysis, but the relict fuel assemblage was consistent across all structures.

Archive: NRHE (intended)

Funder: University of Stirling and Historic Environment Scotland

Mark Thacker – University of Stirling