Preliminary research on potential raw material sources for dolomitic lime mortars at St. John’s convent at Müstair, Switzerland

Author(s): Giovanni Cavallo, Marta Caroselli, Albert Jornet, Patrick Cassitti
Paper category: Proceedings
Book title: Proceedings of the 5th Historic Mortars Conference
Editor(s): José Ignacio Álvarez, José María Fernández, Íñigo Navarro, Adrián Durán, Rafael Sirera
ISBN: 978-2-35158-221-3
e-ISBN: 978-2-35158-222-0
Publisher: RILEM Publications SARL
Publication year: 2019
Pages: 628-641
Total Pages: 14
Language : English

Abstract: The Benedictine convent of St. John at Müstair (UNESCO world heritage site) in
Grisons, Switzerland, preserves a huge amount of well-documented (dolomitic)
archaeological mortar samples dated from the Carolingian to the Baroque Age (8th to
18th century). In the medieval period, the architecture of the Val Müstair and the
surrounding regions was characterized by stone and mortar constructions. The
geological overview of the area around the monastery indicates that dolomitic rocks
are widely available and the production of lime was a common practice in the Müstair
valley as demonstrated by the presence of mortar mixers, lime-kilns and local
toponyms.
As part of an ongoing research project, the question about the potential source(s) of
the raw materials for the production of the binder of the historic mortars was posed.
The proposed research is based on the close relationship between the geological raw
materials and the underburnt relics (lime lumps) found in the archaeological mortars.
Textural features and mineralogical composition were investigated by combining
Polarizing Light Microscopy (PLM) and X-ray Powder Diffraction (XRPD) analysis.
Results indicate that the textural evidence (sometimes) retained by underburnt relics
of dolomitic rocks cannot be used as possible criteria for provenance studies due to
the high variability of dolomite crystal size, fabric and heterogeneity within the same
group and at the scale of individual samples. However, the presence of silicate phases
may suggest potential proxies.

Online publication : 2019
Publication type : full_text
Public price (Euros) : 0.00