Stone Architectural Decoration in Burji Era: The Northern Mausoleum in the Khanqah of Al-Nasir Faraj Ibn Barquq (Cairo). Contribution to the Knowledge and Conservation Assessment

none6The conservation of monuments in Cairo represents a complex matter, influenced by the cultural context, the intrinsic features of a vast and heterogeneous architectural heritage, and the environmental conditions. Monument vulnerability levels strongly need to be systematized to delineate adequate programs of control, management, and intervention. Despite their leading role in the Egyptian architectural heritage, many monuments experience a critical state of conservation. Here, we report the results of a multi-scale investigation of the northern mausoleum in the complex of the Khanqah of Al-Nasir Faraj Ibn Barquq, located in the Islamic cemetery of Al-Qarafa Al-Kubra (Cairo, Egypt). Our research aims to increase the knowledge on the decorative stones used in the mausoleum and their decay processes. The investigation has been focused on the two areas of the building covered by a colored stone-slabs pattern: the floor and the qibla wall. A detailed architectural survey, carried out through photogrammetric techniques, provided a three-dimensional morphological knowledge of the mausoleum, upgrading the available surveys made about 50 years ago. The distribution of the materials has been verified by visual analysis, integrated by the first detailed mineralogical and petrographic characterization made on this mausoleum. The digital survey of the stone surfaces and the mineralogical, chemical, and petrographic analyses allowed a systematic mapping of the decay phenomena and some insights on the morphological alteration of single elements. The obtained results indicate a capillary rise of groundwaters and airborne pollution as the main degradation processes.openAlba Santo; Francesco Di Benedetto; Carlo Garzonio; Elena Pecchioni; Teresa Salvatici; Michele CoppolaSanto, Alba; DI BENEDETTO, Francesco; Garzonio, Carlo; Pecchioni, Elena; Salvatici, Teresa; Coppola, Michel

Characterization protocol of Florentine historical mortars for absolute dating

The raw materials used in the realization of a mortar provide information on the supply areas, original recipes and ancient technologies used to realize a building or an artefact. The raw materials utilized may vary over time, so they may be useful to give an indication of its relative dating. In this field, from the pioneering studies of Labeyrie and Delibrias, (1964) and Stuiver and Smith, (1965), was evaluated the possibilities to radiocarbon dating of historical mortars; this research field still open, since may present many issues in its application. In principle, the carbon fraction datable is represented by calcite (CaCO3) resulting from the hardening of the quicklime (calcium hydroxide, Ca(OH)2) that reacts with CO2 from the atmosphere. The lime binder and lump (un-mixed portion of lime in an aerial mortar) represent the portions that must be isolated from other carbon sources to accurately date mortars. Previous research shows that suitable and proper sampling of mortar samples is of fundamental importance for a conclusive radiocarbon analysis. In recent years, a complete characterization of the mortar before radiocarbon dating was strongly encouraged (Cantisani et al. 2021). The minero-petrographic characterization is the first step to identify the type of mortar and to develop an efficient analytical approach that allows to select the most suitable component of mortar for absolute dating. This work is aimed at mortar characterizing of an important architectural Cultural Heritage in Florence (Italy), Palazzo Medici Riccardi, to understand the building technique, the choice of raw materials, the history of its construction and, possibly, the presence of mortar datable fraction. A correct sampling and characterization procedures allow to know the composition of the binder, the nature of the aggregate, the presence of lumps, the carbonate origins etc. Therefore, to reduce the cost and time of dating, it is necessary to utilize always a fully characterized sample, consisting of a calcite binder, to be subjected subsequently to analysis to accelerator mass spectrometry (AMS) for dating. The research proposes on operative protocol applied on 12 mortar masonry samples of Palazzo Medici Riccardi, composed by: i) a preliminary in-depth characterization of mortar specimens, by means of multi-analytical techniques such as OM, XRPD, TGA, SEM-EDS, OM-CL for a chemical, minero-petrographic and physical characterization fields; ii) non-destructive analyses of datable samples selected, using XRPD, OM-CL and ATR-FTIR (Calandra et al. 2022). The combined use of characterization techniques is the key to obtaining more evidence regarding the composition of the samples to be dated. The selection protocol has made it possible to choose several samples for dating, thanks to which the history of the construction of Palazzo Medici Riccardi will be further explored

Stones for the production of binding materials in Florence area (Tuscany, italy)

From the Roman times to nowadays the exploitation of natural resources has been of primary importance for the expansion and developments of cities and population in general. As long as for more precious natural materials, like gold and silver, even the exploitation of limestones and other lithotypes of stones for building purposes, as the production of quicklime, hydraulic lime and cements, has covered and still has a great importance (Cantisani et al., 2018; Fratini et al. 1994). The limestone exploitation to produce mortar and concrete in the territories of Florence and Prato has been active in the area from the Roman times (Cantini et al., 2017; Raneri et al., 2018). The main goal of this paper is to characterize the different lithotypes useful to the production of cement and limes for mortar production in this area by mean of chemical, mineralogical and petrographic studies and by defining their physical and mechanical properties. This study analyses stone samples from different quarries, one from the province of Prato, Mt. Calvana, and two quarries from the province of Florence, Settimello and Greve in Chianti. A mapping of these quarries and a comparison between the chemical, mineralogical and petrographic characteristics and physical and mechanical properties of these lithotypes are made

Conservation of Paleontological Finds: the Restoration Materials of the “Problematica Verrucana”

The materials used in the historical restoration of a fossil collection named “Problematica Verrucana”, have been studied in order to contribute to the creation of a catalogue of restoration materials used in the past. Due to the complexity of the mixtures used with different purposes to restore fossil finds, an extractive technique has been employed in order to separate the compounds soluble in solvents with different polarities. Using this procedure several components, even when found in small amounts, have been identified. The chemical composition of the organic and inorganic compounds used in the restoration material has been determined using extractive procedure, FT-IR and 1H-NMR spectroscopies. A preliminary macroscopic characterisation and mineralogical and petrographical analyses have also been performed on the inorganic filling materials found in several samples. The different compositions of various materials used in the restoration of this fossil collection might be related to the particular conservative and esthetic functions of the product applied on the find

Migration without interbreeding: Evolutionary history of a highly selfing Mediterranean grass inferred from whole genomes

Wild plant populations show extensive genetic subdivision and are far from the ideal of panmixia which permeates population genetic theory. Understanding the spatial and temporal scale of population structure is therefore fundamental for empirical population genetics –and of interest in itself, as it yields insights into the history and biology of a species. In this study we extend the genomic resources for the wild Mediterranean grass Brachypodium distachyon to investigate the scale of population structure and its underlying history at whole-genome resolution. A total of 86 accessions were sampled at local and regional scales in Italy and France, which closes a conspicuous gap in the collection for this model organism. The analysis of 196 accessions, spanning the Mediterranean from Spain to Iraq, suggests that the interplay of high selfing and seed dispersal rates has shaped genetic structure in B. distachyon. At the continental scale, the evolution in B. distachyon is characterized by the independent expansion of three lineages during the Upper Pleistocene. Today, these lineages may occur on the same meadow yet do not interbreed. At the regional scale, dispersal and selfing interact and maintain high genotypic diversity, thus challenging the textbook notion that selfing in finite populations implies reduced diversity. Our study extends the population genomic resources for B. distachyon and suggests that an important use of this wild plant model is to investigate how selfing and dispersal, two processes typically studied separately, interact in colonizing plant species

Migration without interbreeding: evolutionary history of a highly selfing Mediterranean grass inferred from whole genomes

Wild plant populations show extensive genetic subdivision and are far from the ideal of panmixia which permeates population genetic theory. Understanding the spatial and temporal scale of population structure is therefore fundamental for empirical population genetics – and of interest in itself, as it yields insights into the history and biology of a species. In this study we extend the genomic resources for the wild Mediterranean grass Brachypodium distachyon to investigate the scale of population structure and its underlying history at whole-genome resolution. A total of 86 accessions were sampled at local and regional scales in Italy and France, which closes a conspicuous gap in the collection for this model organism. The analysis of 196 accessions, spanning the Mediterranean from Spain to Iraq, suggests that the interplay of high selfing and seed dispersal rates has shaped genetic structure in B. distachyon. At the continental scale, the evolution in B. distachyon is characterized by the independent expansion of three lineages during the Upper Pleistocene. Today, these lineages may occur on the same meadow yet do not interbreed. At the regional scale, dispersal and selfing interact and maintain high genotypic diversity, thus challenging the textbook notion that selfing in finite populations implies reduced diversity. Our study extends the population genomic resources for B. distachyon and suggests that an important use of this wild plant model is to investigate how selfing and dispersal, two processes typically studied separately, interact in colonizing plant species