Control of the urban pigeon Columba livia population and the preservation of common swift Apus apus and bats Chiroptera during the restoration of the Ghirlandina tower in the city of Modena (Italy)

Ferri, M., Ferraresi, M., Gelati, A., Zannetti, G., Domenichini, A., Ravizza, L., Cadignani, R

La Torre Ghirlandina, storia e restauro

Storia della Torre Ghirlandina e del restaur

La Torre Ghirlandina, il restauro e il terremoto

A meno di un anno dal completamento del restauro che l’ha restituita alla città nel pieno splendore, la torre simbolo di Modena è stata duramente colpita dagli eventi sismici del 20 e 29 maggio 2012. Tutto sommato il monumento ha retto bene alle forti scosse; la torre è rimasta stabile anche grazie agli interventi antisismici di cerchiatura realizzati nel 2011. Il danno principale è stata la fratturazione della lastra decorata di “Sansone che smascella il leone”. Questa breve nota illustra i risultati principali del restauro e i danni prodotti alla torre dalla crisi sismica del maggio 2012

The impressive stone variety on the walls of the Ghirlandina Tower: a world record for the Modena UNESCO Site?

The detailed petrographic and paleontological study of the more than 10.000 slabs covering the medieval Ghirlandina tower (XI-XIV century) at the Modena UNESCO world heritage site revealed the presence of 20 different types of stone. The stones are: Rosso Ammonitico, Scaglia rossa, pietra di Vicenza, pietra di Aurisina fiorita, pietra di Aurisina granitello, trachyte, pietra d’Istria, bardiglio, Carrara ordinario, Proconnesian marble, Candoglia/Ornavasso marble, alpine marble, bronzetto, travertine, Pantano sandstone, M. Pastore sandstone, Scabiazza sandstone, biancone, pietra di Chiampo, cipollino.The reason for this impressive number of stones comes from the medieval practice of re-use of Roman architectural elements from public buildings and funerary monuments from necropolis now laying buried by alluvial sediments at about 5 m depth. Additional rock types were introduced in later restorations and even more recently, such as during the 1973 restoration works.This impressive collection of ornamental stones on the external cover of a tower appears to be an extraordinary and unique example.LUGLI S., 2010. Dall’Egitto all’Istria: viaggio tra le pietre di Modena. Atti del Convegno “Geologia urbana di Modena: sostenibilita’ ambientale e territoriale” 21/11/2008, Modena. Geologia dell’Ambiente, 2/2010, 31-41. LUGLI S., 2010. Le pietre naturali del Palazzo Comunale. In: “Le pietre di Modena, nuovi spazi nell’antico Palazzo Comunale”. Edizioni Artestampa, Modena. 46-49.LUGLI S., PAPAZZONI C.A., GAVIOLI S., MELLONI C., ROSSETTI G., TINTORI S. E ZANFROGNINI R., 2009, Le pietre della Torre Ghirlandina. In “La Torre Ghirlandina un progetto per la conservazione”, a cura di R. Cadignani. Luca Sossella Editore. 96-117. LUGLI S., PAPAZZONI C.A., PEDRAZZI S., ROSSETTI G., TINTORI S. E. 2009. La grandiosa rosa di pietra, analisi litologica del rosone del Duomo di Modena. Taccuini d’Arte, 81-91

Micropaleontological analysis of the “Pietra di Vicenza” from the Cathedral and the Ghirlandina Tower of Modena (N Italy): a tool for provenance recognition.

A comprehensive survey of the stones covering the external walls of the Cathedral and the Ghirlandina Tower in Modena, both built between the XI and the XIV century, has been recently completed as a part of the scientific background needed for the restoration works, which are still in progress.The map shows the presence, among others, of numerous slabs of the stone commercially known as Pietra di Vicenza, which includes Paleogene limestones coming from the Lessini-Berici area (Veneto, northern Italy). Since the Middle Age, re-use of stones coming from the despoliation of Roman monuments is attested by documents, we can hypothesize that at least part of the Pietra di Vicenza was originally quarried out in Roman times. On the other hand, the presence of different varieties of Pietra di Vicenza suggests that it has been used also for later restorations.The micropaleontological analysis of the fossil content has been used as a powerful tool to identify the provenance of the stones, allowing to distinguish different ages and depositional paleoenvironments.The observation of thin sections allowed to recognize at least 4 different microfacies.The microfacies 1 and 2 have been dated to the Early Oligocene, according to the presence of the index fossils Nummulites cf. fichteli, N. cf. vascus, Asterigerina rotula haeringensis, and Praerhapydionina delicata. Facies 1 contains abundant miliolids and articulate coralline algae, whereas facies 2 is dominated by crustose coralline fragments, with less miliolids. The depositional paleoenvironment was very shallow, probably in the back-reef, with microfacies 2 slightly more distal than microfacies 1.The microfacies 3 contains quite frequent nummulites (some of them large-sized), abundant crustose coralline algae (rhodoliths are common), and some large fossils such as bivalves, echinoids, corals, etc. Its age is not always the same, varying from the Middle Eocene (with Nummulites cf. ptukhiani) to the Late Eocene (with Nummulites cf. fabianii); Early Oligocene index fossils have also been identified (Nummulites cf. vascus, Asterigerina rotula haeringensis). These characteristics indicate a “shoal” facies in the middle-outer platform/ramp.The microfacies 4 is dominated by Discocyclina, Orbitoclypeus, Asterocyclina, rather large Nummulites, and some planktonic foraminifera. The age is limited to the Eocene but no index fossils were recognized. The paleoenvironment could be in the outer platform/ramp, near the transition to the basin.The examination of ornamental stones coming from archaeological excavations in the Modena area allowed to determine that most of the Pietra di Vicenza quarried by the Romans belongs to microfacies 1 and rarely to n. 2 or 3. After fieldwork and sampling in the Lessini and Berici Mts., we recognized the microfacies 1 and 2 only in the basal levels of a quarry active since pre-Roman times near the village of Costozza (Berici Mts.).The microfacies 3 has been found in several localities both of Lessini and Berici Mts., usually in quarries only recently exploited. The microfacies 4 is very similar to the commercial Pietra di Nanto, presently extracted near the homonymous village in the Berici Mts. The historical documentation attests its use for restorations of the Cathedral only during the restoration work of 1898-1903

The Pietra di Vicenza microfacies: recognizing the provenance of building stones from the Cathedral and the Ghirlandina Tower (Modena, Italy).

The Cathedral and the Ghirlandina Tower in Modena (XI - XIV century), represent a masterpiece of the Romanesque art, included into the UNESCO World Heritage List. In recent years, some stone falling turned the attention to their need of urgent restoration. This in turn revealed the lack of modern detailed studies on the rock slabs used to cover the external walls of both monuments that were originally identified by Bertolani & Rossi (1971) and Bertolani (1984) .The systematic recognition of the rock slabs of the Ghirlandina Tower and of the façade and northern side of the Cathedral allowed to map nine different rock types, among which the so-called Pietra di Vicenza is one of the most prominent (Fig. 1).The commercial name Pietra di Vicenza indicates a set of Paleogene limestones with different mechanical and aesthetic properties (Cornale & Rosanò, 1994). The common trait is their provenance either from the Berici Mts. or from the southern Lessini Mts. (Vicenza).The historical documentation attests the medieval use of slabs deriving from despoliation of Roman monuments. However, part of the original slabs were replaced with different varieties of Pietra di Vicenza during subsequent restorations.In order to determine the original Roman stones, a preliminary survey has been carried out both on local museum collections (Capedri, 2005) and on recent archaeological findings in the Modena urban area. Then, the results have been compared with samples collected in several quarries in the Veneto area (Fig. 2).The palaeontological analyses, in particular the microfossil assemblages, allowed to distinguish four main Pietra di Vicenza microfacies:Microfacies 1 (Fig. 3)Well-sorted packstone, with abundant miliolids and coralline algae (commonly fragmented); rare specimens of Nummulites sp.Microfacies 2 (Fig. 4)Moderately-sorted packstone/grainstone, with abundant coralline algae (commonly crusts, less frequently fragments) and subordinate miliolids; some small Nummulites sp.Microfacies 3 (Fig. 5)Moderately-sorted to unsorted packstone, with abundant crustose coralline algae, small to medium-sized Nummulites spp., rare miliolids.Microfacies 4 (Fig. 6)Unsorted packstone, with small to large Nummulites spp. and Discocyclina spp.The analysis revealed a wide variety of fossil assemblages in the Oligocene limestones from the Berici Mts. and the southern Lessini Mts. According to our observations on the archaeological material, practically all the Pietra di Vicenza used by Romans belongs to microfacies 1 (Fig. 7). The latter has been found only in the basal part of the Oligocene limestones near Costozza (Figs. 8-9), where exploitation is documented since pre-Roman times. This village is located on the eastern margin of the Berici Mts., where the limestone strata lie close to the Bacchiglione River, which was probably used as waterway for transportation.Microfacies 2, although not found in the roman artifacts, is probably heteropic to microfacies 1.Microfacies 3 has been used during restorations of various ages including those repairing damages of World War II (1949). Restorations of 1898-1903 used only slabs belonging to the microfacies 4 (Fig. 10).BibliographyBertolani M. (1984) - Note sulla natura delle pietre usate nel Duomo di Modena in Lanfranco e Wiligelmo. Il Duomo di Modena. Edizioni Panini, Modena, pp. 298-305.Bertolani M. & Rossi A. (1971) - Osservazioni sul rivestimento lapideo della Torre Ghirlandina a Modena. in Deputazione di Storia Patria per le Antiche Province Modenesi, Modena, 93-101.Capedri S. (2005) - I materiali naturali utilizzati nei repertori del Museo Lapidario Estense, in Il Museo Lapidario Estense, catalogo generale, a cura di N. Giordani e G. Paolozzi Strozzi, Venezia, 509-513.Cornale P. & Rosanò P. (1994) - Le pietre tenere del vicentino - uso e restauro. Associazione Artigiani della Provincia di Vicenza, p. 176

NDTs in the monitoring and preservation of historical architectural surfaces

Diagnosis and post intervention monitoring are central action in a new approach related to the conservation and maintenance of architectural surfaces, which takes into account not only the restoration moment, but also the behaviour of the materials over time. In this regard, ND techniques could give a significant contribution in the definition of the conservation state. This paper collects part of the authors experience in regard to NDTs used in the monitoring of historical surfaces and in the study of the transformation during CH maintenance. Furthermore, it deals with the problem of the definition of suitable indicators, taking into account the know-how of our research groups in connection to specific case studies