Historic Mortars from Tuquoy, Westray, Orkney Islands: a SEM-EDS study

Research output: Book/ReportCommissioned report

Abstract

The principal aim of this investigation, was to assess the evidence for the composition of the provenance of the binder in three historic mortar specimens from Tuquoy. In addition, general description of the mortar specimens supplied reveals features of interest, particularly fragments of slag in one specimen. These can contain information indicative of the composition of materials calcined for production of the binder, and also conditions of firing, such as temperature and reduction / oxidation during production.
Analysis of the specimens from Tuquoy revealed a variable composition and texture of mortar between samples, characterised in the main by the differences in the non-binder fraction (the aggregate, additives and/or inclusions). Overall, the binder fraction in TWO-4 and 8, was composed of a high-Ca carbonate, with only minor (< a few %) evidence of other elements such as Mg, S or Fe. This was indicative of course, of a similarly composed carbonate source, certainly comparable to the biogenic sources seen as aggregates in the mortars, something also supported by the evidence of pseudomorph textures found in calcined lime inclusions, similar in dimension to the biogenic aggregates. The binder phase in sample TWO-9 has a consistently higher content of Si and Al, possibly indicating either a hydraulic composition or the incorporation of fin grained silicate minerals incorporated as part of the aggregate.
Original languageEnglish
Place of PublicationPaisley
PublisherUniversity of the West of Scotland
Commissioning bodyUniversity of the Highlands and Islands
Number of pages33
Publication statusPublished - Oct 2018

Fingerprint

mortar
Mortar
Binders
Energy dispersive spectroscopy
scanning electron microscopy
Scanning electron microscopy
Carbonates
Chemical analysis
Textures
texture
pseudomorph
Silicate minerals
carbonate
silicate mineral
slag
Lime
Slags
lime
provenance
Hydraulics

Keywords

  • mortar
  • masonry
  • Orkney
  • scanning electron microscopy

Cite this

Hughes, J. (2018). Historic Mortars from Tuquoy, Westray, Orkney Islands: a SEM-EDS study. Paisley: University of the West of Scotland.
Hughes, John. / Historic Mortars from Tuquoy, Westray, Orkney Islands : a SEM-EDS study. Paisley : University of the West of Scotland, 2018. 33 p.
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abstract = "The principal aim of this investigation, was to assess the evidence for the composition of the provenance of the binder in three historic mortar specimens from Tuquoy. In addition, general description of the mortar specimens supplied reveals features of interest, particularly fragments of slag in one specimen. These can contain information indicative of the composition of materials calcined for production of the binder, and also conditions of firing, such as temperature and reduction / oxidation during production.Analysis of the specimens from Tuquoy revealed a variable composition and texture of mortar between samples, characterised in the main by the differences in the non-binder fraction (the aggregate, additives and/or inclusions). Overall, the binder fraction in TWO-4 and 8, was composed of a high-Ca carbonate, with only minor (< a few {\%}) evidence of other elements such as Mg, S or Fe. This was indicative of course, of a similarly composed carbonate source, certainly comparable to the biogenic sources seen as aggregates in the mortars, something also supported by the evidence of pseudomorph textures found in calcined lime inclusions, similar in dimension to the biogenic aggregates. The binder phase in sample TWO-9 has a consistently higher content of Si and Al, possibly indicating either a hydraulic composition or the incorporation of fin grained silicate minerals incorporated as part of the aggregate.",
keywords = "mortar, masonry, Orkney, scanning electron microscopy",
author = "John Hughes",
note = "Report commission on study of archaeological mortars from medieval ecclesiastical structure in Westray, Orkney Islands. Work carried out to determine greater detail on question of lime provenance in thin section specimens of mortar. Part of larger archaeological investigation of the site.",
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Hughes, J 2018, Historic Mortars from Tuquoy, Westray, Orkney Islands: a SEM-EDS study. University of the West of Scotland, Paisley.

Historic Mortars from Tuquoy, Westray, Orkney Islands : a SEM-EDS study. / Hughes, John.

Paisley : University of the West of Scotland, 2018. 33 p.

Research output: Book/ReportCommissioned report

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T1 - Historic Mortars from Tuquoy, Westray, Orkney Islands

T2 - a SEM-EDS study

AU - Hughes, John

N1 - Report commission on study of archaeological mortars from medieval ecclesiastical structure in Westray, Orkney Islands. Work carried out to determine greater detail on question of lime provenance in thin section specimens of mortar. Part of larger archaeological investigation of the site.

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Y1 - 2018/10

N2 - The principal aim of this investigation, was to assess the evidence for the composition of the provenance of the binder in three historic mortar specimens from Tuquoy. In addition, general description of the mortar specimens supplied reveals features of interest, particularly fragments of slag in one specimen. These can contain information indicative of the composition of materials calcined for production of the binder, and also conditions of firing, such as temperature and reduction / oxidation during production.Analysis of the specimens from Tuquoy revealed a variable composition and texture of mortar between samples, characterised in the main by the differences in the non-binder fraction (the aggregate, additives and/or inclusions). Overall, the binder fraction in TWO-4 and 8, was composed of a high-Ca carbonate, with only minor (< a few %) evidence of other elements such as Mg, S or Fe. This was indicative of course, of a similarly composed carbonate source, certainly comparable to the biogenic sources seen as aggregates in the mortars, something also supported by the evidence of pseudomorph textures found in calcined lime inclusions, similar in dimension to the biogenic aggregates. The binder phase in sample TWO-9 has a consistently higher content of Si and Al, possibly indicating either a hydraulic composition or the incorporation of fin grained silicate minerals incorporated as part of the aggregate.

AB - The principal aim of this investigation, was to assess the evidence for the composition of the provenance of the binder in three historic mortar specimens from Tuquoy. In addition, general description of the mortar specimens supplied reveals features of interest, particularly fragments of slag in one specimen. These can contain information indicative of the composition of materials calcined for production of the binder, and also conditions of firing, such as temperature and reduction / oxidation during production.Analysis of the specimens from Tuquoy revealed a variable composition and texture of mortar between samples, characterised in the main by the differences in the non-binder fraction (the aggregate, additives and/or inclusions). Overall, the binder fraction in TWO-4 and 8, was composed of a high-Ca carbonate, with only minor (< a few %) evidence of other elements such as Mg, S or Fe. This was indicative of course, of a similarly composed carbonate source, certainly comparable to the biogenic sources seen as aggregates in the mortars, something also supported by the evidence of pseudomorph textures found in calcined lime inclusions, similar in dimension to the biogenic aggregates. The binder phase in sample TWO-9 has a consistently higher content of Si and Al, possibly indicating either a hydraulic composition or the incorporation of fin grained silicate minerals incorporated as part of the aggregate.

KW - mortar

KW - masonry

KW - Orkney

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Hughes J. Historic Mortars from Tuquoy, Westray, Orkney Islands: a SEM-EDS study. Paisley: University of the West of Scotland, 2018. 33 p.