Colline Metallifere (Tuscany, Italy)

Since the 1980s, in Italy, and Tuscany in particular, considerable experience has been developed in research on the mining landscape in relation to the geography of population, with particular attention to the Medieval period. Numerous research projects carried out in the Colline Metallifere areas of Livourne and Grosseto by the Archaeology Department of the University of Sienna (Prof. Riccardo Francovich) have revealed the huge potential offered by this territory for the study of the population, extraction and production dynamics of the pre-industrial period as well as the necessity for rigorous surveillance of the remains of these activities which have been progressively eroded by recent and massive extraction activities and by the current development of housing and infrastructure. In the Livourne Colline Metallifere area, we have already advanced from the research phase to the creation of a fully operational Archaeo-mining Park which has made it possible to protect an extensive territory containing a wealth of pre-industrial and industrial archaeological evidence, including the mining village of Rocca San Silvestro. In the Grosseto province, the Colline Metallifere grossetane Technological and Archaeological Park was recently created. The aim of this institution is to preserve and enhance historical and archaeological heritage of prime importance which twenty years of research have contributed to uncover across a vast territory.Depuis les années 80, en Italie, et en particulier en Toscane, une expérience considérable d’étude du paysage minier en relation avec la géographie du peuplement s’est développée, avec une attention particulière pour la période médiévale. Les nombreuses recherches menées dans la zone des Colline Metallifere de Livourne et de Grosseto par le Département d’Archéologie de l’Université de Sienne (prof. Riccardo Francovich) ont mis en évidence le potentiel énorme de ce territoire pour l’étude des dynamiques de peuplement, d’extraction et de production d’époque préindustrielle, ainsi que la nécessité d’une surveillance rigoureuse des vestiges de ces activités progressivement érodés par les activités d’extraction récentes et massives et par le développement de l’habitat et des infrastructures actuellement en cours. Dans la zone des collines métallifères de Livourne, nous sommes déjà passés de la phase de recherche à l’institution d’un Parc Archéominier pleinement opérationnel qui a permis de protéger un vaste territoire riche en témoignages archéologiques préindustriels et industriels comprenant le village minier de Rocca San Silvestro. Dans la province de Grosseto a été récemment créé le Parc Technologique et Archéologique des Colline Metallifere de Grosseto. Cette institution a pour objectif de préserver et mettre en valeur un patrimoine historique et archéologique de grande importance que vingt ans de recherches ont contribué à mettre au jour sur un vaste territoire

A 19 to 17 Ma amagmatic extension event at the Mid-Atlantic Ridge: Ultramafic mylonites from the Vema Lithospheric Section

A >300 km long lithospheric section (Vema Lithospheric Section or VLS) is exposed south of the Vema transform at 11°N in the Atlantic. It is oriented along a seafloor spreading flow line and represents ∼26 Ma of accretion at a single 80 km long segment (EMAR) of the Mid-Atlantic Ridge. The basal part of the VLS exposes a mantle unit made mostly of relatively undeformed coarse-grained/porphyroclastic peridotites that were sampled at close intervals. Strongly deformed mylonitic peridotites were found at 14 contiguous sites within a ∼80 km stretch (∼4.7 Ma interval); they are dominant in a time interval of 1.4 Ma, from crustal ages of 16.8 to 18.2 Ma (mylonitic stretch). Some of the mylonites are "dry," showing anhydrous high-T deformation, but most contain amphibole. The mylonitic peridotites tend to be less depleted than the porphyroclastic peridotites on the basis of mineral major and trace elements composition, suggesting that the mylonites parent was a subridge mantle that underwent a relatively low degree of melting. The Sr, Nd, and O isotopic composition of the amphiboles is MORB-like and suggests either that seawater did not contribute to their isotopic signature or that their isotopic ratios re-equilibrated during fluid circulation in the upper mantle. Four 40Ar/39Ar ages, on three amphiboles separated from the peridotites, are close to crustal ages predicted from magnetic anomalies, confirming that the amphiboles formed close to ridge axis. We propose that crustal accretion at the EMAR segment has been mostly symmetrical for the 26 Ma of its recorded history, except for the ∼1.4 Ma interval of prevalent ultramafic mylonites (mylonitic stretch) that may record a period of quasi-amagmatic asymmetric accretion of oceanic lithosphere close to the ridge–Vema transform intersection, possibly with development of detachment faults. This interval may correspond to a thermal minimum of the subridge upwelling mantle, marking the transition from a period of decreasing to one of increasing mantle melting below the EMAR segment

Shaping Mediterranean landscapes:The cultural impact of anthropogenic fires in Tyrrhenian southern Tuscany during the Iron and Middle Ages (800–450 BC / AD 650–1300)

Charcoal analysis, applied in sediment facies analysis of the Pecora river palaeochannel (Tyrrhenian southern Tuscany, Italy), detected the occurrence of past fire events in two different fluvial landforms at 800–450 BC and again at AD 650–1300. Taking place in a central Mediterranean district adequately studied through palaeoenvironmental and archaeological research, the investigation determined land changes, time phases and socio-economic driving forces involved in dynamic processes of fire. The fire sequences had purely anthropogenic origins and were linked to forest opening and reduction by local communities. Introduced by the Etruscans, fires dated to 800–450 BC involved mainly the forest cover on the hilly slopes, ensuring agricultural exploitation. From AD 650, fires contributed to Medieval upstream reclamation and vegetation clearing of flat swamplands. From AD 850 to 1050, the use of fire spread over a wider area in the river valley, increasing arable lands. Between AD 1150 and 1300, fires belonged to a regional forest clearance phase. Medieval fire episodes had a paramount importance in shaping and determining the character of the Tuscan Mediterranean landscape. From AD 850, Medieval fire clearing influenced regional vegetation history contributing to the decline of the dominant deciduous Quercus woodland. Open habitats became the new form of a clearly detectable agricultural landscape from AD 950. The use of fire clearing and the resulting landscape changes in the Pecora river valley depended on the political strategies adopted by Medieval authorities and marked, in fact, the progression of a cultural landscape still characterizing central Tyrrhenian Italy

Lo scavo dell’Allumiera di Monteleo. Nuovi dati per la produzione dell’allume alunitico nel tardo Medioevo

The presence of alunite and "natural alums" is documented in different areas of the Colline Metallifere district, where the main ore deposits are located. It is here that the research conducted by the University of Siena has identified various alum mines (open casts and galleries) and the remains of some important alum productive sites (allumiere) dating back to the 15th-16th centuries. The investigation of the Monterotondo Marittimo district in particular, started in 2004 with an accurate topographic campaign, has produced valuable indications regarding the settlement dynamics and the exploitation of natural resources. From 2008 to 2016, the excavation of an early Modern Age production site located in the heart of an alunite deposit, the "Allumiere di Monteleo", provided an exceptional opportunity to explore the various steps involved in the processing of raw materials, and highlighting the versatility of such production centers. The research has offered us the possibility to cross different sources (archival; archaeological; geological; cartographic) to investigate a wide diachrony of the use of raw materials. Starting from the evaluation of these systems of sources we will propose here a diachronic rereading of the valorisation of natural resources in the light of the data coming from the most recent campaigns on the production complex of the Allumiere di Monteleo