Friend, C. R L., Dye, J. and Fowler, M. (2007). New field and geochemical evidence from vitrified forts in South Morar and Moidart, NW Scotland:. J Archaeol Sci 34 (10). Vol 34(10), pp. 1685-1701.

Title
Title
The title of the publication or report
Title:
New field and geochemical evidence from vitrified forts in South Morar and Moidart, NW Scotland:
Subtitle
Subtitle
The sub title of the publication or report
Subtitle:
further insight into melting and the process of vitrification
Issue
Issue
The name of the volume or issue
Issue:
J Archaeol Sci 34 (10)
Series
Series
The series the publication or report is included in
Series:
Journal of Archaeological Science
Volume
Volume
Volume number and part
Volume:
34 (10)
Page Start/End
Page Start/End
The start and end page numbers.
Page Start/End:
1685 - 1701
Biblio Note
Biblio Note
This is a Bibliographic record only.
Biblio Note
The ADS have no files for download on this page but further information is available online, normally as an electronic version maintained by the Publisher, or held in a larger collection such as an ADS Archive. Please refer to the DOI or URI listed in the Relations section of this record to locate the information you require. In the case of non-ADS resources, please be aware that we cannot advise further on availability.
Publication Type
Publication Type
The type of publication - report, monograph, journal article or chapter from a book
Publication Type:
Journal
Abstract
Abstract
The abstract describing the content of the publication or report
Abstract:
New field and laboratory work was carried out on two vitrified forts, Rhubh Aird Ghamhsgail near Arisaig and The Torr near Acharacle. Fieldwork confirms that both are constructed from rubble largely comprising local psammitic Moine Supergroup rocks and that their walls are relatively well preserved with large portions of vitrified material remain, particularly at The Torr, where remnants of up to four courses of stone facing occur. The preserved wall fills comprise mostly psammitic rubble set in a dark brown, vesicular, glassy to aphanitic matrix that in many places preserves evidence of downward flow. Conventionally, vitrification is explained through combustion of timber interlacing within the walls leading to melting that has been modelled in the granite system. However, considering Iron Age smelting technology, this leads to problems in obtaining high temperatures (≥1000 °C) over tens of metres of wall length. Geochemical analysis of the vitrification indicates that modelling the melting within the granite system is incapable of providing a partial melt matching the composition of vitrification. At The Torr, pelite fragments have been found near the base of the wall where partial melt occurs as black bubbles. In these fragments it appears that micas (largely biotite) have formed the melt via the reaction biotite + quartz = sanidine + orthopyroxene + liquid which takes place at temperatures c. 850 °C. Quench crystals in the melt include orthopyroxene, plagioclase, spinels, ilmenite, magnetite, anatase and apatite confirming that it was not a granite melt. These melted fragments are found next to material with biotite that, superficially, appears unmelted, suggesting that some of the heating took place perhaps away from the edifice and unmelted residue was utilised as part of the rubble fill, suggesting that in situ partial melting of the rubble is unlikely. However, in other parts of the edifice heat affected, yet unmelted, fragments are dominant. The new evidence indicates that vitrification occurred at lower temperatures than previously modelled and thus the melts could have been achieved more easily than previously thought.
Author
Author
The authors of this publication or report
Author:
C R L Friend
J Dye
M B Fowler
Year of Publication
Year of Publication
The year the book, article or report was published
Year of Publication:
2007
Locations
Locations
Any locations covered by the publication or report. This is not the place the book or report was published.
Subjects / Periods:
Timber (Auto Detected Subject))
Wall (Auto Detected Subject))
Iron Age (MIDAS)
Granite System (Auto Detected Subject))
Walls (Auto Detected Subject))
Forts (Auto Detected Subject))
Source
Source
Where the record has come from or which dataset it was orginally included in.
Source:
Source icon
BIAB (The British & Irish Archaeological Bibliography (BIAB))
Relations
Relations
Other resources which are relevant to this publication or report
Relations:
URI: http://www.sciencedirect.com/science/journal/03054403
Created Date
Created Date
The date the record of the pubication was first entered
Created Date:
19 Sep 2007