ABSTRACT LXXIII, August 2004 n. 3:
Gilberto Artioli and Mattia
Dugnani - Crystallographic texture analysis:
applications in mineralogy and archaeometry
Abstract - Texture analysis by diffraction methods has greatly advanced in the last
few years because of instrumental and computational developments, and it is
now to be considered a routine tool for the analysis of crystallite orientation
in a wide variety of materials, including rocks, industrial products, and
archaeological samples. The advances in the experimental measurements are
mainly linked to the use of flexible experimental setups at large radiation
sources, such as synchrotrons and neutron sources, which allow faster data
collection, the use of samples of any size, and complete coverage of texture
and reciprocal space. The developments in the data analysis are mainly related
to the use of the full diffraction profiles in place of the single-peak methods.
This produces pole figures and orientation distribution functions (ODF) that
are statistically more significant and less prone to biases in the data analysis.
Furthermore it opens the possibility of analysis of complex polyphasic materials,
which are hard to characterize by other experimental techniques. Applications
are discussed concerning the texture analysis of metamorphic rocks and archaeological
samples.
Claudio D’Amico, Elisabetta
Starnini, Giorgio Gasparotto and Massimo Ghedini - Eclogites, jades and other HP-metaophiolites employed for prehistoric
polished stone implements in Italy and Europe
Abstract - Prehistoric polished stone tools are now fairly well-known from a petrographic
point of view in Northern Italy. Many more than one thousand implements sampled
from the most important sites and collections (axes, adzes, chisels, some
ornaments and various tools fragments), have been analysed. These artefacts
were commonly employed from the Neolithic period onwards for working wood
and cutting the forest trees. Surface optical observations, density, thin
sections, XRD, microprobe analyses and bulk chemistry have been employed,
alone or in combination, for petrographic study oriented to archaeometric
interpretation.
Alpine eclogites, jades (Na-pyroxenites) and other
minor HP (High Pressure) metaophiolites dominate the polished stone lithology
of Northern Italy, being at least 70% and often surpassing 90% of stone
materials in single sites. Petrographic, geochemical, minerochemical, textural
data of the studied rocks are described and discussed in some detail. A number
of new definitions are introduced.
The provenance of the raw material is identified as
being NW Italy, essentially Piedmont and Liguria. These regions represent one
of the few geological zones in the world where alpine eclogites and jades
occur, both as primary outcrops in the High Alps, alluvial and morainic deposits
along the valleys, and Oligocene conglomerates in the Northwestern Apennines.
The dominance of eclogites and jades among the
prehistoric polished stone tools represents a lithic selection of cultural
significance. This selection seems to be justified by litho-technological (best
mix of hardness, toughness and density) and aesthetic (fine green colours,
translucency) reasons, which caused the exclusion of other, elsewhere common,
lithologies.
Germana Barone, Catia
Branca, Vincenza Crupi, Salvatore Ioppolo, Domenico Majolino, Giusy Puglisi,
Grazia Spagnolo and Gabriella
Tigano - Archaeometric
analyses on ceramics from Sicilian Greek colonies: a contribution to the knowledge
of Messina, Gela and Agrigento production
Abstract - Several samples of the two important archaeological areas of eastern Sicily,
Messina in north-eastern Sicily, and Gela and Agrigento in central-southern
Sicily, were analysed by optical analysis under a polarized light microscope,
XRD, FT-IR, XRF, ICP-MS and ICP-OES. Petrographic and chemical data processing
allowed to characterise pottery fabrics of Greek colonies in Sicily and to
identify the principal elements that distinguish the different local productions
(Messina, Gela and Agrigento) between them and from those imported (Greece).
Patrizia Santi, Fabrizio
Antonelli, Alberto Renzulli and Patrizio Pensabene - Leucite phonolite millstones from the Orvieto
production centre: new data and insights into the Roman trade
Abstract -
The leucite phonolite lava from quarries located near Orvieto (about 100
km northward from Rome) has represented a volcanic rock in great demand and
highly prized for manufacturing millstones in the Roman period. Good abrasive
property and rough vescicular surface of this lithotype from the Roman Volcanic
Province (Vulsini District) gave to the mills an excellent grinding capacity
through the time. The quarries and production centre of Orvieto were located
few kilometers from the Tiber River, an impressive natural waterway along
which the Romans could transport millstones down to the Tyrrhenian Sea. Because
of several findings of leucite phonolite millstones throughout the Mediterranean,
we can suppose that from the port of Ostia
Antica (located at the estuary of the Tiber River) these artefacts were shipped
in large number (as cargoes) or used as ballasts until the localities of destination.
This is supported by the presence, at the bakery (Mill Building) of Ostia
Antica of several well-preserved Pompeian-style rotary millstones made of
the Orvieto leucite phonolite (LP), as shown by petrographic and geochemical
analyses. Moreover, in the same archaeological site, some containers for kneading
the bread dough (kneading-machine) consist of less vesciculated leucite tephritic
phonolites with lower porphyritic index (LTP1 and LTP2).
Franca Cimmino, Francesco Faccini and Andrea
Robbiano - Stones
and coloured marbles of Liguria in historical monuments
Abstract - The presence of a great number of different lithotypes contributes to
the extremely variable geological landscape of Liguria: its rocks are one
of the main reasons of the natural beauty of this region and a mean used by
people to economically exploit their land and to express themselves in art
and architecture.
Many rock types are locally used, but in Italy and abroad some
particular stones («Ardesia», «Pietra di Finale», «Pietra di Promontorio», Mt.
Zatta or Mt. Gottero Sandstones) and some coloured marbles («Rosso Levanto»,
«Verde Polcevera» and «Portoro») are very known.
These materials are today widely used as decorative
tombstones, both indoor and outdoor, of the historical buildings and in the
local craftsmanship.
alessandro cavallo, biagio bigioggero
(deceased), annita colombo and annalisa tunesi - The Beola: a dimension
stone from the Ossola Valley (NW Italy)
Abstract - The Ossola Valley (north-western Italy)
is well known in Italy both for its geological features and for the exploitation
of various rock types. Among these the most valuable gneiss is the Beola used
as building or ornamental stone since the Roman Age. The different varieties
of Beola are exploited in four main areas according to their geological and
structural setting: Vogogna (Fobello-Rimella mylonitic schists - Austroalpine),
Beura-Villadossola (Monte Rosa nappe orthogneisses – Upper Penninic), Trontano-Domodossola
(Orselina-Moncucco-Isorno orthogneisses – Upper Penninic) and Montecrestese-Crevoladossola
(Monte Leone nappe orthogneisses – Lower Penninic). This paper deals with
the historical use of the Beola and its quarries and presents new data on
the petrographical, geochemical and mechanical features of the different varieties.
The mineralogical composition of the Beola varieties is quite homogeneous:
Qtz+Kfs+Pl+Bt+WM; the main differences are related to the rock fabric and
to the presence of accessory/secondary minerals. The «Quarzite» Verde from
Vogogna has the worst value of wear resistance (14.17 mm; Amsler), the Beola
Argentea from Montecrestese-Crevoladossola has the best one (4.06 mm); whereas
the other rock types have quite homogeneous values (5-8 mm). The flexural
strength is remarkably different as function of the load applied parallel
or perpendicular to the rock fabric (foliation or lineation) ranging from
19.5 to 11.3 MPa for the Beola Grigia and from 16.1 to 6.0 MPa for the Beola
Ghiandonata of the Beura-Villadossola area. The water absorption value is
usually low (0.27-0.44%) for all the Beola types. Based on the geo-mechanical
features and the aesthetic parameters, the Beola Bianca, Favalle and subordinately
the Beola Grigia are the most valuable varieties of the Ossola district.
Abstract - Industrial wastes rich in toxic heavy metals are produced in high amounts
yearly. As other hazardous wastes, they require special, expensive disposal,
and they may represent a serious environmental and health issue in case of
heavy metal dispersion. Petrology may offer useful tools to effectively inertize
hazardous industrial wastes and eventually recycle them back in industry.
Mineral phases like oxides and aluminosilicates, occurring in natural rocks
and employed in the ceramic industry, have a high potential for long-term
bonding a wide variety of refractory as well as low-melting heavy metals.
These resistant phases may then be used to incorporate a wide range of hazardous
metal components in waste during inertization treatments. Experimental work
was done on petrological models like the MgO-SiO2-Al2O3
(MAS) system and its little known extensions to Cr2O3
(MASCr) as well as to the low-melting PbO (PMASCr). Experiments were planned
with different bulk compositions and on a wide range of temperatures in order
to test feasibility and efficiency of a petrology-based inertization of highly
chromiferous and Cr-Pb-rich industrial wastes, as those from tanneries and
from galvanic processes. Run products exploring the refractory MASCr system
between 1250°C and 1560°C showed that the addition of Cr contributes to stabilize
the refractory, Cr-rich phases of the MAS system and to lower the thermal
minimum of the system by approximately 100°C. Different Cr-bearing phases
are dominant in the different portions of the system, from spinels in the
most Mg-rich bulk compositions to sapphirine and mullite in the least Mg-rich
ones. Glass occurs in all runs and is Cr-poor. Cr2O3
content of Cr-hosting phases in the run products may vary between 100 wt%
in pure eskolaite to 60 wt% maximum in spinel, 30 wt% in sapphirine down to
12-23 wt% in mullite. Spinels and sapphirine and the most abundant and most
interesting phases in the view of inertization. Experiments in the unknown
PMASCr system were planned (a) to cope with compositions of galvanic sludge
(Crtot + Pb oxides > 30 wt%, molar Cr:Pb about 1:1), and (b)
to induce simultaneous crystallization of Pb-feldspar and Cr-bearing spinel
between 950°C and 1050°C, from subsolidus and from melt conditions (after
short high-temperature treatment at 1350°C). The planned association of Pb
feldspar and Cr-rich spinel (with Cr2O3 up to 60 wt%)
occurs in all runs, even at low temperature, and in association with terms
of the eskolaite-corundum solid solution. Spinel and Pb feldspar are the most
abundant phases crystallized except in the runs treated at high temperature,
where Cr-poor, Pb-bearing glass can overcome Pb feldspar. Cr and Pb are therefore
completely separated in distinct phases. Both groups of experiments are highly
encouraging for waste-oriented applications: heavy metals like Cr and Pb can
be efficiently bondend in crystalline phases and they are sharply fractionated,
thereby allowing further recovery of the economically interesting Cr-rich
phases for recycling and safe disposal of the remaining inertized waste.
Lorenzo Lazzarini
- Archaeometric aspects of
white and coloured marbles used in antiquity: the state of the art
Abstract - As is well known, the identification of the quarry of ancient marble artefacts
is of the utmost interest to archaeologists and art historians. Scholars of
different disciplines have been trying for more than a century such an identification
by means of a unique laboratory analysis without positive results. To-date
the best probabilities of success are obtained by combining together two or
more analytical techniques. The paper presents a short history of the important
studies, namely those regarding the most frequently used combinations, with
particular reference to the petrographic examination of a thin section and
the determination of the C & O stable isotopic ratios on the same sample.
Such a combination takes advantage of the best existing database for the marbles
most commonly used in antiquity. Of these are reported the essential information
on their quarries, periods of use and specific bibliography, together with
the MGS (Maximum Grain Size) and isotopic diagrams useful for their identification.
Patrizia Tucci
and Paola Morbidelli
- «Apulian marbles» of the Ostuni District (south-eastern
Murge, Apulia, Italy). Identification and characterisation of ancient quarries
for archaeometric purposes
Abstract - The so-called «Apulian marbles» have been, and still are, widely used
as both building and ornamental materials. The lithotypes exploited in antiquity
in nine quarries identified in the Ostuni district (South-Eastern Murge, Apulia,
Italy) were studied. This research aims at: i) characterising, from minero-petrographic
and geochemical points of view, the outcropping lithotypes (this kind of study
being scarce or lacking in literature); ii) attributing them to their geological
formation of provenance; iii) furnishing a data-base for comparisons (features
of quarry materials), in order to solve archaeometric problems related to
the various archaeological sites and monuments occurring in South-Eastern
Murge. With these aims, on quarry samples, minero-petrographic, palaeontological,
chemical and, only for some samples, isotopic and scanning electron microscopy
analyses were carried out. The results allow us to conclude that, of the nine
quarries, two (Lamasanta Grande and Costamerlata) are open in the «Calcare
di Caranna» Formation (Campanian-Maastrichtian), two (Viale Oronzo and Ostuni-Villanova)
in the «Calcare di Altamura» (Coniacian-lower Campanian); one (Via dei Colli)
in the «Calcare di Ostuni» (Campanian-Maastrichtian); two (behind the Messapic
Rosara quarry) in the «Calcare di Caranna» Ostuni variety (Campanian-Maastrichtian);
and the last two (Tre Torri Hotel and Melpignano) in the megabreccia (Maastrichtian-Paleocene).
Riccardo Cattaneo-Vietti,
Giorgio Bavestrello, Carlo Cerrano, Maria Chiara Chiantore, Luciano Cortesogno
and Laura Gaggero - Interactions between aquatic biological systems
and silica
Abstract - The negative effects of quartz on biological systems are well known, from
a clinical point of view, since the XVIII century, anyway the influence of
quartz on the marine benthic organisms and communities is underestimated.
Interactions between organisms and minerals (biomineralogy) could play a major
role on the life cycle of a species and on the spatial distribution and structure
of marine and freshwater benthic communities. Various biosystems, at different
levels of complexity (cell, organism, species, and community) show, in fact,
the ability to recognise, select, react, and possibly use the mineral fraction.
A negative influence of quartz on the biological activity has been demonstrated,
due to the toxic activity of the silanolic radicals on the surface of the
crystalline quartz, which interferes with animal metabolism.
The aim of this paper is to review the selective response by benthic
organisms to the quartz presence and evaluate the primary role of quartz in
affecting the development, settlement and growth of many species. Such
selectivity may cause spatial anomalies in species composition, diversity and
biomass in marine and freshwater communities and, consequently, have important
consequences on basic and applied ecology.
Maurizio Petrelli, Diego Perugini, Beatrice Moroni and Giampiero Poli - Travertine, a building stone
extensively employed in Umbria from Etruscan to Renaissance age: provenance
determination using artificial intelligence technique
Abstract - This work is focused on determining the provenance of travertine stones
employed in the construction of some monuments in Umbria (Italy) from the
Etruscan to the Renaissance age. To this aim we propose a new methodological
approach based on the combined use of petrographic observations and statistical
analysis of geochemical data. Analyses are performed on samples from monuments
and quarries whose activity is documented since ancient times. Statistical
analysis is performed using the conventional Principal Component Analysis
and two new methods based Artificial Intelligence (a Self-Organizing Map and
a Fuzzy Logic System).
Results show that the Principal
Component Analysis is a very poor technique to determinate travertine
provenance because of its low discriminative power as stated using samples from
the different quarries. On the contrary, the two Artificial Intelligence
techniques show an excellent discriminative power and their application to
monument samples produces very good and concordant results, although some
uncertainties in the determination of travertine for some monuments are
observed. These uncertainties can be solved, in most cases, by combining
results of the statistical analysis with petrographic observations.
It is evidenced that a local
provenance of travertine employed in the construction of ancient buildings is a
common feature at any age in the past. In addition, it is suggested that a
non-local provenance may furnish information on the historical background in
which a monument was conceived and built.
Results from this study indicate
that the combined use of Artificial Intelligence techniques and petrographic
observations is a powerful tool for provenance determination of travertine
employed in the construction of ancient buildings.
Giuseppe Maria Bargossi,
Fabio Gamberini, Giorgio Gasparotto, Gian Carlo Grillini and Marta Marocchi - Dimension and ornamental stones from the Tosco-Romagnolo
and Bolognese Apennine
Abstract - The hilly territory of the eastern Emilia-Romagna up to the Apennine watershed,
also comprising part of the Romagna Toscana, represents in Italy the main
sandstones producer, along with the Pietra Serena of Firenzuola and Marradi
and the Pietra Serena from the Savio valley. Minor districts, not less important
for the local economy are also present, such as those exploiting the selenitic
gypsum of Brisighella, Borgo Rivola, Borgo Tossignano, Bologna and the «Crystalline
Alabaster» of Torriana, the San Marino calcarenites, the Montefeltro limestone
and the Montovolo and Castel d’Aiano sandstones. We should not forget the
historical-cultural heritage constituted by the now dismissed quarries of
the Varignana, Sasso Marconi, Monghidoro, Castiglione dei Pepoli and Porretta
sandstones, employed since the Villanovian, Etruscan, Roman, Medieval and
Renaissance ages; as well as unique materials, locally employed, such as the
Montecodruzzo limestone, the Spungone calcarenite, the Labante travertine,
the euphotide gabbro and the Mantesca and San Zanobi serpentinites.
The aim of the authors is to give in
this work some historical elements of knowledge on dimension and ornamental
stones and not to put forward a research work regarding the geology and
stratigraphy of the area.
Alessandro Cavallo, Biagio Bigioggero
(deceased), Annita Colombo and Annalisa Tunesi - The Verbano Cusio
Ossola Province: a land of quarries in northern Italy (Piedmont)
Abstract - The Verbano Cusio Ossola province (Piedmont, north-western Italy) is one
of the most important quarrying areas due to the peculiarity of its exploited
rock types; actually this is one of the few areas in Italy with ornamental
stones represented mainly by orthogneisses such as Serizzo and Beola and subordinately
by granites, marbles and finally ultramafites and carbonatic rocks. The exploitation
dates back to the Roman period and is nowadays strongly improved also because
of the development of technology. This work describes the historical use,
the petrography, the physical and chemical properties (for orthogneisses)
and the exploitation technology of the different rock types, evidencing, for
the metamorphic rocks occurring in the Ossola Valley, the strong connection
between textural features and geological setting which produces several varieties
within each rock type.
Riccardo Sandrone, Annita
Colombo, Laura Fiora, Mauro Fornaro, Enrico Lovera, Annalisa Tunesi and Alessandro Cavallo - Contemporary natural stones from the Italian
western Alps (Piedmont and Aosta Valley Regions)
Abstract - At present about 60 different kinds of stones are quarried in the Italian
Western Alps, most of which are metamorphic rocks (gneiss, ophicalcite, marble
and quartzite) and, to a lesser extent, magmatic (granite, syenite and diorite),
with an overall production of 380.000 m3 in the year 2002. This
work synthetically illustrates their geologic and petrographic characteristics,
gives essential historical information and examines the technical, environmental
and economic aspects of their extraction and production.
Giacomo
Chiari and David Scott
- Pigment analysis: potentialities and problems
Abstract - The field of pigment analysis is explored through a series of examples
taken from the authors’ work experience. Some analyses are easy to make, other
may require the combination of various techniques, still others require the
use of sophisticated equipment such a synchrotron or neutron diffraction analyses.
Sometimes the results obtained do not agree with the accepted theories about
the use of specific pigments (e.g. Egyptian Blue), or a new, unexpected substance
is found to be used as a pigment (e.g. magnesium oxalate or lead sulfate).
Investigations into illuminated manuscripts revealed the presence of a variety
of verdigris, only matched by our laboratory synthesis of this variant. The
discovery that the binders used were of size, resulted in the presence of
copper-proteinate paints from reaction of the media with verdigris. The red
pigment in a manuscript by Von Ems was found to be made from rhubarb, which
is the first time this colorant has been detected from illuminated manuscripts. Examination
of an Egyptian ushabti of the New Kingdom revealed a layer of tridymite white
pigment overlying a calcite ground. This unusual discovery may signify
that the Egyptian pigment palette is much more extensive than previously thought.
Isabella Turbanti Memmi
- Pottery production and
distribution: the contribution of mineralogical and petrographical methodologies
in Italy. State of the art and future developments
Abstract - The aim of the present paper is to provide a review of the contribution
of mineralogical petrographic methodologies to the archaeoemtric study of
pottery in Italy. After a brief history of the archaeometric research of pottery
and a summary of the mainly used analytical techniques, the more relevant
topics in pottery studies have been reviewed. The topics covered include:
the provenance studies, using thin-section petrography and chemical analysis;
the reconstruction of the technology used in pottery production, through a
combination of bulk (XRD, DTA-TGA, FTIR etc.) and in situ techniques (SEM-EDS,
EMPA, Raman etc.). The surface coating technology production have also been
reviewed. In particular: permeable slips (engobe), impermeable slips (classic
black gloss and red slip) and glassy coatings (glazes, lustre). Some future
developments are also emphasized: a wider use of high resolution and spectroscopic
techniques (HRTEM; Raman); more studies on the relationships between paste
technology and object functionality; investigation of the changes in chemical
composition and microstructure occurring as result of use and weathering of
pottery during burial.
Gino Mircole Crisci,
Marco Franzini, Marco Lezzerini, Tiziano Mannoni and Maria Pia Riccardi
- Ancient mortars and their binder
Abstract - Numerous works which have characterised binders in historical buildings
(Fratini and Giovannini, 1990; Chiari et al., 1992; 1996a; 1996b; Collepardi,
1993; Fratini et al., 1994; Mannoni and Giannichedda, 1996; Franzini et al.,
1999; 2000a; 2000b) reveal that the production of such materials, and of mortars
and plasters, was not a simple process. There is increasing evidence that
blends of natural materials were studied in ancient building sites and that
different technical solutions were adopted to resolve specific problems.
The reported case studies represent a variety of construction contexts
and periods, and different issues were addressed in each study.
Each construction site found a unique solution which
was obtained by «correcting» the parameters of locally available geomaterials
and involved the study of complex analytical strategies suited to each specific
case.
The study of hydraulic mortars used to construct the
Tower of Pisa is an example of how scientific investigation can help
reconstruct ancient production recipes that were never recorded in any manual
of the period.