Use of physical-chemical-biological techniques for the analysis of an arrowhead

The study of metal artifacts has long been the subject of study by many researchers who are trying to reconstruct the habits and customs of vanished civilizations. In particular, the chemical-physical characterization is important in order to acquire information on the origin of the raw materials used for their manufacture, on the production techniques and on the investigation of corrosion phenomena [1,2]. The aim of this study was the chemical-physical-biological characterization of an arrowhead coming from archaeological excavations of the acropolis of Heracleia, stored in the National Archaeological Museum of Siritide in Policoro (Basilicata, Italy). Through through a multi-analytic approach (Optical microscope, Raman, XRF, XPS, biological analysis), the characterization of the arrowhead was carried out and the results obtained gave information about the metals used and the state of corrosion. Raman analysis highlighted the corrosion linked to the presence of Lead Dioxide (Plattnerite) as reported in Figure 2., data confirmed also by the XPS analysis.Since plattnerite is one of the corrosion products of lead [3,4], the information obtained from the Raman and XPS analysis can also provide indications and soil chemical-physical characteristics (e.g. humidity, pH, chlorine content, and others) of the archaeological environment in which the arrowhead was found. All this demonstrates and confirms how important diagnostics is to retrieve information from a past time

Manufatti metallici: cultura umanistica e scientifica strettamente interconnessi

Secondo Tucidide, lo scopo dell'archeologia era di "dimostrare di ricostruire il passato non solo attraverso le fonti ma anche attraverso prove scientifiche esatte” evidenziando, quindi, la stretta correlazione che esiste fra cultura umanistica e scientifica (Artioli, 2010). Ecco che i reperti archeologici rinvenuti in aree di scavo o in ritrovamenti subacquei, debitamente interrogati possono raccontarci, in maniera dettagliata, tradizioni, usi, itinerari di viaggio, scambi commerciali delle civiltà che hanno popolato in passato i territori (Parmeggiani, 2003). La presente ricerca si è focalizzata sullo studio di reperti metallici ritrovati duranti gli scavi archeologici nell’area Siris di Policoro (Matera) al fine di ottenere informazioni sulle caratteristiche chimico – fisiche degli oggetti, sulle tecnologie di realizzazione e sullo stato di degrado/corrosione. I reperti, consistenti in: specillo (Fig.1), punta di freccia, tappo di fiaschetta, bastoncino in piombo, arma in ferro, punta di giavellotto e fibula sono stati analizzati attraverso una sinergia di metodologie non distruttive quali Microscopia Ottica (MO), Fluorescenza dei Raggi X (XRF), Diffrazione di Raggi X (XRD), X-ray Photoelecton Spectroscopy (XPS) e Spettroscopia Raman. Sui reperti sono state anche condotte indagini microbiologiche per verificare la presenza di biodeteriogeni. I principali risultati possono essere così riassunti: le analisi XRD mostrano che i campioni sono costituiti essenzialmente da leghe di ferro e alluminio e ossidi di ferro e rame, sovente con incrostazioni di quarzo e calcite, le analisi XRF oltre a rivelare gli elementi maggiori quali Fe, Cu e Zn, rivelano per alcuni campioni tracce di Zn e Pb. Nello specifico, “Spec3” , la cui scheda museale riportava come composizione metallica 100% in ferro, è risultata essere una lega di Cu e Zn con tracce di Fe e Pb .Nessun biodeteriogeno risulta essere presente sugli oggetti analizzati. Fine ultimo della ricerca consisterà nell’identificazione e pianificazione di successivi interventi green di risanamento e consolidamento

A geo-chemo-mechanical study of a highly polluted marine system (Taranto, Italy) for the enhancement of the conceptual site model

The paper presents the results of the analysis of the geo-chemo-mechanical data gathered through an innovative multidisciplinary investigation campaign in the Mar Piccolo basin, a heavily polluted marine bay aside the town of Taranto (Southern Italy). The basin is part of an area declared at high environmental risk by the Italian government. The cutting-edge approach to the environmental characterization of the site was promoted by the Special Commissioner for urgent measures of reclamation, environmental improvements and redevelopment of Taranto and involved experts from several research fields, who cooperated to gather a new insight into the origin, distribution, mobility and fate of the contaminants within the basin. The investigation campaign was designed to implement advanced research methodologies and testing strategies. Differently from traditional investigation campaigns, aimed solely at the assessment of the contamination state within sediments lying in the top layers, the new campaign provided an interpretation of the geo-chemo-mechanical properties and state of the sediments forming the deposit at the seafloor. The integrated, multidisciplinary and holistic approach, that considered geotechnical engineering, electrical and electronical engineering, geological, sedimentological, mineralogical, hydraulic engineering, hydrological, chemical, geochemical, biological fields, supported a comprehensive understanding of the influence of the contamination on the hydro-mechanical properties of the sediments, which need to be accounted for in the selection and design of the risk mitigation measures. The findings of the research represent the input ingredients of the conceptual model of the site, premise to model the evolutionary contamination scenarios within the basin, of guidance for the environmental risk management. The study testifies the importance of the cooperative approach among researchers of different fields to fulfil the interpretation of complex polluted eco-systems

3T-phlogopite from Kasenyi kamafugite (SW Uganda): EPMA, XPS, FTIR, and SCXRD study

A 3T mica polytype from Kasenyi (south west Uganda) kamafugite was studied by Electron Probe Microanalysis (EPMA), Single Crystal X-ray Diffraction (SCXRD), micro-Fourier Transform Infrared Spectoscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS) in order to characterize its crystal chemistry and the relationships with samples from the same rock but showing different stacking sequence. EPMA data gave: SiO2 = 38.7(2), Al2O3 = 13.08(9), MgO = 20.4(2), TiO2 = 4.8(1), MnO = 0.03(3), FeOtot = 5.51(9), Cr2O3 = 0.90(7), NiO = 0.11(5), SrO = 0.03(3), ZnO = 0.04(3), ZrO2 = 0.01(2), K2O = 9.64(5), Na2O = 0.29(1), BaO = 0.15(5), F = 0.13(5) and Cl = 0.01(1) wt%. The analysed sample may be classified as a Ti-rich, F-poor mica with a composition in the phlogopite- annite join end members. X-ray photoelectron spectroscopy provided Fe2+/Fe3+ and O2- /OH equal to ~ 0.75 and 7.14, respectively, which are in agreement with the results of previous Mössbauer investigation on the BU1 sample and with the structural formula of the studied crystal. Infrared spectra showed, in the OH- stretching region (~ 3740-3600 cm-1 cm-1), a shoulder at ~ 3660 cm-1 which is assigned to MgMgFe3+-OH--K-O2- local configurations. No evidences of vacancy substitutions were observed. Single crystal X-ray refinement using anisotropic displacement parameters was performed in the P3112 space group and converged to R1 = 4.34 and wR2 = 3.33 %. Unit cell parameters are: a = b = 5.3235(3) and c = 30.188(2) Å. Geometrical and chemical considerations point to a disordered cation distribution over T1 and T2 tetrahedral sites, whereas partial cation ordering characterizes the octahedral sites with M1 = M2 ≠ M3. Tetrahedral bond/edge lengths distortion and angle variances parameters evidence more distorted polyhedra in 3T polytype than those found in coexisting 1M and 2M1 polytypes. Finally, the overall crystal chemical features indicates the occurrence in the studied sample of the following substitution mechanisms: tetraferriphlogopite [IVFe3+ IVAl]; Ti-oxy [VIM2+ + 2 (OH)  VITi4+ + 2 (O2–) + H2] and Al, Fe3+, Cr-oxy [VIM2+ + (OH)  VIM3+ + O2– + ½ (H2)]; Al, Fe3+-Tschermak [VIM2+ + IVSi4+  VI(Al3+, Fe3+) + IVAl3+]; XIIK+ + IVAl3+  IVSi4+ + XII