The monastery of St. John in Müstair, a UNESCO world heritage site, preserves archaeological remains and stone structures dated from the 8th century to the present. It has been extensively studied archaeologically so that numerous samples of historical materials, including mortar, are available for study. In addition to that, some of the structures have been precisely dated with dendrochronology. The monastery is located in a region characterized by dolomite rocks and the mortars are therefore of dolomitic nature, being perfectly suited to test the possibility of being dated with 14C. Furthermore, the presence of embedded carbon fragments has provided additional independent data to support or deny the results of mortar dating. A comparison of the results obtained from radiocarbon (14C) dating of bulk mortars, sieved fractions enriched in binder, lime lumps and carbon fragments, for two samples is presented, in relation to the petrographic characterization and the mineralogical phase content. This preliminary study shows that the dating of 14C can potentially be applied to the mortar of Müstair, as results in accordance with the established chronologies have been obtained for one sample. However, if the dolomitic sand contamination is very high, further studies are needed to develop a specific sample preparation technique.

中文翻译：

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圣约翰修道院（瑞士）的白云岩砂浆的放射性碳测年：初步结果

位于联合国教科文组织世界遗产 Müstair 的圣约翰修道院保留了 8 世纪至今的考古遗迹和石制建筑。它已在考古学上进行了广泛的研究，因此可以研究包括砂浆在内的大量历史材料样本。除此之外，一些结构已经用树木年代学精确地确定了年代。修道院位于以白云岩为特征的地区，因此研钵具有白云质性质，非常适合测试与14C. 此外，嵌入碳碎片的存在提供了额外的独立数据来支持或否认砂浆测年的结果。从放射性碳获得的结果的比较（14C) 介绍了两个样品的散装砂浆、富含粘合剂的筛分部分、石灰块和碳碎片的年代测定，与岩相特征和矿物相含量有关。这项初步研究表明，14C 可以潜在地应用于 Müstair 的砂浆，因为已经从一个样品中获得了符合既定年表的结果。但是，如果白云质砂污染非常高，则需要进一步研究以开发特定的样品制备技术。