Distinction between consecutive construction phases by combined microscopic study and quantitative pore space analysis: Case study of Horn's Bastion, Riga Castle (Latvia)

Abstract

• Attribution of dolostones and mortars to various construction phase of Riga Castle. • Mercury intrusion porosimetry data and petrographic image analysis allowed for distinction of dolostones from various construction periods. • Quantitative microstructural data (grain size characteristics) are useful for distinction of mortars from various construction periods. A combination of quantitative microscopy (petrographic image analysis) and mercury intrusion porosimetry (pore space textural analysis) allowed for a clear distinction of natural stone and mortar samples from two separate construction periods of the Riga Castle (Latvia) in the 13th and 14th c. For the task of the separation of construction phases, pore space textural characteristics seem to be superior over qualitative (descriptive) characteristics of the rock fabrics of natural building stone – dolostone, whilst quantitative microstructural data (grain size characteristics) are more useful than pore space textural characterisation of mortars.