Raman microspectroscopy of garnets from S-fibulae from the archaeological site Lajh (Slovenia)

Kos, Saša (author), Dolenec, Matej (author), Lux, Judita (author), Dolenec, Sabina (author)

Garnets (19 pieces) of Late Antique S-fibulae from the archaeological site at Lajh-Kranj (Slovenia) were analysed with Raman microspectroscopy to obtain their mineral characteristic, including inclusion assemblage. Most garnets were determined as almandines Type I of pyralspite solid solution series; however, three garnets showed a higher Mg, Mn and Ca contents and were determined as almandines Type II. Most significant Raman bands were determined in the range of 169–173 cm$^−$$^1$ (T(X$^2$$^+$)), 346–352 cm$^−$$^1$ (R(SiO$_4$)), 557–559 cm$^−$$^1$ (ν$_2$), 633–637 cm$^−$$^1$ (ν$_4$), 917–919 cm$^−$$^1$ (ν$_1$), and 1042–1045 cm$^−$$^1$ (ν$_3$). Shifting of certain Raman bands toward higher frequencies was the result of an increase of the Mg content in the garnet composition, which also indicates the presence of pyrope end member in solid garnet solutions. Inclusions of apatite, quartz, mica, magnetite, ilmenite, as well as inclusions with pleochroic or radiation halo and tension fissures (zircon), were found in most of the garnets. Rutile and sillimanite were found only in garnets with the highest pyrope content. Spherical inclusions were also observed in two garnets, which may indicate the presence of melt or gas residues. The determined inclusion assemblage indicates the formation of garnets during medium- to high-grade metamorphism of amphibolite or granulite facies. According to earlier investigations of the garnets from Late Antique jewellery, the investigated garnets are believed to originate from India.

• Language: English
• Keywords: garnets, inclusions, S-fibulae, Late Antiquity, provenance, Raman microspectroscopy, XRF spectroscopy
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2020
• Number of pages: 21 str.
• Numbering: Vol. 10, iss. 4, art. 325
• PID: 20.500.12556/RUL-128700
• UDC: 55
• ISSN on article: 2075-163X
• DOI: 10.3390/min10040325
• COBISS.SI-ID: 1568606
• Publication date in RUL: 23.07.2021

Record is a part of a journal

• Title: Minerals
• Shortened title: Minerals
• Publisher: MDPI AG
• ISSN: 2075-163X
• COBISS.SI-ID: 519985177

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
• Licensing start date: 04.04.2020

Secondary language

• Language: Slovenian
• Keywords: granati, vključki, S-fibule, pozna antika, provenienca, ramanska mikrospektroskopija, spektroskopija XRF

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P2-0273
• Name: Gradbeni objekti in materiali

• Funder: ARRS - Slovenian Research Agency
• Project number: P1-0195
• Name: Geookolje in geomateriali