1,721,003 research outputs found
Ceramics: Chemical and Petrographic Analysis
No full textAncient ceramics, the most abundant findings in archaeological sites since prehistory, are mobile objects that could have been exchanged/traded far away from their production center. Their provenance and production technology represent, therefore, an important issue that can be studied through petrographic and chemical analyses to discuss cultural differences, exchange routes, and technological developments. Using petrography, the occurrence (especially in coarse ware) of mineral/ rock markers allows to link their production with specific geological regions, while microstructural and textural features of the ceramic body can supply information on their production technology in terms of forming techniques and paste recipes. When dealing especially with fine ware, the bulk geochemical composition can identify specific production centers through comparison with ceramic reference groups, and reveal possible preparation procedures of the base clay, such as depuration and mixing. Ceramic coatings such as slips, paints and glazes can be analyzed under a microscope and their elemental composition can be further assessed by micro-chemical and isotopic analyses
Foreword: Multidisciplinary study of the Sarno Baths in Pompeii (Naples, Italy): Preface
No full textCaratterizzazione archeometrica preliminare di materiali ceramici provenienti dal territorio di Mondragone (Caserta)
No full textPLASTERS,PAINTINGS AND FLOORS AT POMPEII: ARCHAEOMETRICAL INVESTIGATIONS
No full textA meeting on the methods and application
of thin section petrographic analysis
to archaeological ceramics &
other cultural material
Detrital Cr-spinel in the Šambron-Kamenica Zone (Slovakia): evidence for an ocean-spreading zone in the Northern Vardar suture?
No full textThe Sambron–Kamenica Zone is situated on
the northern margin of the Levoc¡ske ́ vrchy mountains and
Sarisska` vrchovina Highland, where the Central Carpathian
Paleogene joins the Pieniny Klippen Belt. Sandstone outcrops
in this area. From Cretaceous to Late Oligocene in
age, these sediments suggest transport directions from S
and SE. The heavy mineral assemblages of this sandstone
include Cr-spinel grains, mainly displaying types II and III
alpine-peridotite affinities, and are representative of Ocean
Island Basalt volcanism. A sample from Upper Eocene
sediments at Vit’az shows a clear change in Cr-spinel
composition, which turns out to have types I and II peridotite
affinities, and to derive from arc and Middle Ocean
Ridge Basalt volcanism, with sediment transport directions
from SW and WSW. These data indicate major variations
in the Upper Eocene tectonic setting, giving constraints to
paleogeographic reconstruction of the Slovak Central
Carpathians
Firing and post-firing dynamics of Mg- and Ca-rich bricks used in the built heritage of the city of Padua (northeastern Italy)
Full text linkDiverse types of bricks from monuments in the city of Padua (northeastern Italy) were studied using
a multi-analytical approach based on spectrophotometry, X-ray fluorescence (XRF), X-ray powder diffraction
(XRPD), polarized-light optical microscopy (POM) and/or high-resolution scanning electron microscopy with
coupled energy-dispersive X-ray spectroscopy (HRSEM-EDS). The most representative bricks were yellow or
beige and in well-preserved condition. The results showed that they were made of Mg- and Ca-rich illitic clays,
were fired at high temperatures (from 900 to over 950 C), and achieved an incipient vitrification. Two main
processes took place during firing: (i) the development of a Ca-aluminosilicate amorphous phase where very
abundant pyroxene-type crystals were nucleated and (ii) the transformation of the pristine Mg-rich clayey grains
into Mg-silicate mineral phases. The analyses suggest a firing dynamic within a highly reactive and supersaturated
unstable system, particularly rich in calcium and magnesium. There are also signs of the rapid heating
and/or soaking of the bricks and the irregular heat distribution and/or different residence times inside the kilns.
The formation of zeolite and calcite secondary phases was also observed. The former was largely promoted by
the high calcium content of the bodies and the very humid conditions, while the latter was mainly precipitated
from Ca-rich solutions. The preservation of the bricks was enhanced by processes that took place both during
and after firing. Firstly, the significant development of a Ca-rich amorphous phase and of high-temperature
pyroxene-type crystals has provided strength to the bricks. Secondly, the porosity yielded by the firing of the
carbonate-rich clays was almost filled by secondary calcite, which acted as a cementing agent. The information
attained has increased the knowledge of (i) the mineralogical and microstructural changes that take place during
the firing over 900 C of Ca- and Mg-rich illitic clays and (ii) the formation of secondary phases within highly
calcareous bricks laid in very humid environments and affected by Ca-rich solutions. The key role of the Ca- and
Mg-rich raw clays and of the high firing temperatures, in producing high-quality bricks, and of the secondary calcite,
which increased their durability, is highlighted. All these factors have contributed to the better preservation
of the built heritage of the city
Characterization of the pore system of commercial bricks for restoration: a new perspective combining 2D and 3D imaging and traditional methods.
No full textDuring the firing of bricks, mineralogical and textural transformations produce an artificial aggregate characterised by significant porosity. Particularly as regards pore-size distribution and the interconnection model, porosity is an important parameter to evaluate and predict the durability of bricks. The pore system is in fact the main element, which correlates building materials and their environment (especially in cases of aggressive weathering, e.g., salt crystallisation and freeze-thaw cycles) and determines their durability. Four industrial bricks with differing compositions and firing temperatures were analysed with ?direct? and ?indirect? techniques, traditional methods (mercury intrusion porosimetry, hydric tests, nitrogen adsorption) and new analytical approaches based on digital image reconstruction of 2D and 3D models (back-scattered electrons and computerised X-ray micro-Tomography). The comparison of results from different analytical methods in the ?overlapping ranges? of porosity and the careful reconstruction of a cumulative curve, allowed overcoming their specific limitations and achieving better knowledge of the pore system of bricks
Provenance of wine and oil amphorae in northern Adriatic: Archaeometric and epigraphic approaches
Full text linkThis research focuses on the archaeometric analysis of a large set of wine (type Dressel 6A) and oil amphorae (type Dressel 6B and probably funnel necked amphorae) from northern and central Italy, with the main aim of characterizing the various regional productions and trades among them and other production region of the Adriatic coast. Archaeobotanic and archaeological evidence, as well as the geographic context, indicated that both northern and central Italy were devoted to the growth of both grapes for wine production and olive trees. The various stamps recorded on Dressel 6A and Dressel 6B amphorae, the family names of which can be linked to specific regional areas within this territory, attest that numerous production centres were active even in the Cisalpina (northern Italy). The comparison with amphorae and fired local clay material of Romagna and Middle-Adriatic area, allowed to confirm the Middle-Adriatic origin of some series of Dressel 6A and Dressel 6B amphorae, as originally hypothesized for these amphorae
Combined multianalytical approach for the characterization of commercial bricks with a view to their technical use.
No full textBrick is a construction material used in buildings since Roman times and still used in modern constructions for its own technical features and aesthetic qualities. The raw materials and the firing temperatures are closely related with the characteristics of fired products (Riccardi et al., 2009). During the firing process mineralogical and textural transformations occur (and resembles the high-temperature metamorphism) which produces anartificial material characterized by asignificant porosity. Porosity is an important parameter to evaluate the durability of bricks, especially in aggressive environments, e.g. those in which salts and frost are present (Cultrone et al., 2004). This work aims to develop a combined multianalytical approach for studying the relationships between mineralogical-textural and physical-mechanical properties and decay behavior of five types of industrial bricks. They have been chosen in order to define the influence of different compositions and firing temperatures on the development of different mineralogy, micro-texture and porosity
- …
