196,192 research outputs found
Il cantiere della Maestà. Indagini sulla bottega di Simone Martini
No full textIl volume riporta osservazioni, considerazioni e risultati delle analisi svolte sulla Maestà di Simone Martini nel Palazzo Pubblico di Siena in occasione delle operazioni di manutenzione del 2017
Ca-oxalate films on the stones of the medieval architecture: The case-study of Romanesque Churches
No full textTraces of Ca-oxalate films were found on the stone surfaces of stones of some Sardinian medieval Churches of the ‘Giudicati’ period. The study aims to define their distribution and microstratigraphy on the different architectonic stone elements and to clarify their precise roles as result of probable ancient conservation. Ca-oxalate films show a variable color from greyish, to rosy or yellowish and generally they are present on the decorative architectonic elements of monuments. Their thickness is variable (10-50 m) owing to the roughness of the stone surfaces. XRD analyses performed directly on the collected microsamples and on powders gently scraped from their surfaces revealed calcite+weddellite (type 1) in some of them and calcite+weddellite+whewellite (type 2) in others. Preliminary observations at the polarizing microscope showed two different micro-stratigraphies
Coadsorption of NO and H2 at the surface of MgO monitored by EPR spectroscopy. Towards a site specific discrimination of polycrystalline oxide surfaces
No full text
The W-Mo deposit of Perda Majori (SE Sardinia, Italy): a fluid inclusion study of ore and gangue minerals
No full textThe W-Mo deposit of Perda Majori (SE Sardinia) consists of a NW-SE trending quartz vein that crops out for about 500 m in the Salto di Quirra region.
Hercynian low-grade metamorphic rocks, which host the orebody, largely dominate the geology of the area and are themselves intruded and contact metamorphosed by late Hercynian leucogranites and leucogranite porphyries.
Field evidence supports a genetic link between the orebody and the emplacement of the leucogranites.
The ore paragenesis consists chiefly of wolframite, molybdenite, scheelite, pyrite and calcopyrite, while the gangue is formed of quartz, K-feldspar, albite, topaz, micas, fluorite and calcite.
The highest Th (320-420-degrees-C) were found in coarse-grained quartz (Qz I) which also records signs of boiling. Inclusions found in wolframite, giving Th 310-330-degrees-C and the highest recorded salinities (6-7 wt.% NaCl eq.), suggest that ore deposition closely followed the boiling
The white marble quarries of Campiglia Marittima (Livorno, Italy) and the provenance of marble artefacts from Populonia
No full textThe aim of this work was to localize and to sample the ancient
marble quarries of Campiglia Marittima (Livorno,
Italy) in order to characterize them minero-petrographically
(by X-ray powder diffraction and optical microscopy
for thin sections) and isotopically (measuring the
stable C and O isotope ratio by standard mass spectrometry)
to create a first database for use in archaeometric
studies. The results can help distinguish this marble from
that of Carrara and other similar fine-grained marbles
used in antiquity and make it possible to determine the
provenance of different types of Late-Republican artefacts
(mortars, inscriptions, architectural elements, pavements
and sculptures) from the archaeological area of
Populonia. Given the good quality of the marble, further
analyses may be able to shed light on its possible regional
distribution or even its export to neighbouring regions,
also considering Populonia’s strategic position on the important
Tyrrhenian sea trade routes
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