ABSTRACT LXXIV, April 2005 n. 1:
MASSIMO SETTI*, LUIGI MARINONI and FERNANDO VENIALE - Transformation mechanism of lamellar to lath-shaped illite/smectite: observation by SEM Abstract -
During investigation of
the diagenetic processes which occurred in the «varicoloured» clay-shale
formation along the italian Apennines strip, a lithofacies characterised by
the presence of lath-shaped smectite/illite interstratification has been encountered
in a zone affected by tectonic stresses; the occurrence area is located along
the Sangro river valley, at the border between central and southern Italy.
Detailed SEM observations have evidenced that the clay particles show a morphological
transition from flakes to laths. The change occurs via: (i) flattening and thinning
of precursor wavy lamellae; (ii) formation of lath aggregates (where the laths
are oriented at 60°/120° to each another) that are preserving the original
flake contours; (iii) disaggregation of such aggregates into isolated disoriented
laths.
Microanalytical EDAX data indicate only slight chemical changes associated with
the morphotype transition, mainly concerning Mg and Al contents that are increasing-decreasing,
respectively, whereas changes of Si and K amounts were not surely detectable.
Although there are some questions to be clarified (as reaction kinetics, thermal
history and role of water content), the observed morphotype transformation is
interpreted as a solid-state splitting mechanism, probably influenced by mechanical
stresses due to tectonic events and associated chemical changes
GERMANA BARONE*, SALVATORE IOPPOLO, DOMENICO MAJOLINO, CATERINA BRANCA, LIDIA SANNINO, GRAZIA SPAGNOLO and GABRIELLA TIGANO - Archaeometric analyses on pottery from archaeological excavations in Messina (Sicily, Italy) from the Greek archaic to the Medieval age
Abstract - In the
present paper we report for the first time all the results obtained through
a multidisciplinary investigation on some of the most representative ceramic
classes (cooking pottery, tiles, banded, Corinthian B, ionian-massaliote
and pseudo-chian amphorae, Zancle type cups, Chalcidian,
Attic, banded and a immersione wares, ionian
banded B2, black-glazed vessels and a arula sherd) coming from archaeological
excavations in Messina, covering a period from Greek archaic to Medieval age.
The aim of the present work is to characterize the pottery’s production
centers in Messina and to distinguish the local products from the imported ones;
this will help us to get further information on the commercial network involving
the «Strait Area». The samples were analysed by mineralogical-petrographic
and chemical-physical techniques. In particular, X-Ray Diffraction (XRD), thin
section analysis by Optical Microscopy (OM), Fourier Transform Infrared Absorption
(FTIR), X-Ray Fluorescence (XRF), Inductively Coupled Plasma Mass Spectroscopy
(ICP-MS), Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES),
and Scanning Electron Microscopy coupled with X-ray Energy Dispersion (SEM-EDX)
were employed.
The obtained results have evidenced the local production of the coarse potteries
(cooking pottery, tiles), contrary to the ionian-massaliote and pseudo-chian
transport amphorae that result to be imported products from Locri and, in some
cases, from a non located site in Campania; the production of the Corinthian
B type amphorae can be attributed both to a Greek (Corfù) and to
a colonial magno-Greek (Sibari) imported production center. Finally, for what
concerns the fine pottery, the Chalcidian, banded, ionian
B2, a immersione and Zancle potteries result produced
in the «Strait area», whereas the Attic ceramics are imported from
Greek production centers.
Abstract - Foid-bearing syenite cognate xenoliths represent fragments of the upper peripheral parts of the K-phonolitic portions of the 79 AD magma chamber, wrenched during the explosive eruption. Abundant multiphase fluid inclusions are hosted within K-feldspar and coexist with rare silicate melt inclusions. This gives evidence to the exsolution of a magmatic volatile-rich phase from the peripheral parts of the silicate magma chamber. The characterization of daughter mineral assemblage of these fluid inclusions, by SEM-EDS and Raman spectroscopy, indicates two ubiquitous main components: Na-K chlorides (halite + sylvite) and Na-Ca carbonates (calcite ± nahcolite). Microthermometric experiments indicate nearly magmatic trapping temperatures (760°C to 830°C) of the homogeneous chloride-carbonate liquid. Cooling of such liquid produces two immiscible melt phases (chlorides and carbonates) at 455-435°C. This suggests that a hypersaline-carbonate fluid, exsolved from the silicate magma, can further experience another unmixing event that would occur in essentially «post-magmatic» environment.
MARCO LEZZERINI*- The mortars of the "Fortezza delle Verrucole - S. Romano in Garfagnana (LU)"Abstract - — Twenty-one mortar samples taken from the walls in the southwest side of the Fortezza delle Verrucole (IX-XVIII century) – S. Romano in Garfagnana (Lucca, Italy) – have been analysed to characterise their binder and aggregate fractions. The chemical, mineralogical, petrographic and physical data collected on the bulk mortar samples show that the stone walls were built up using different mortars. The mortars with a hydraulic-binder are prevailing on those with an air-hardening lime binder. The older mortars, coming from the walls built before the XV century, were produced mixing lime putty with locally available sands. They are characterized by a sandy aggregate with grain size from medium to very coarse and by a number of snow-white lumps, due to a not complete mixing between binder and aggregate. This last feature suggests that the mortars were prepared, as it was usual in ancient times, hand-mixing the lime putty added to the sand. Hydraulic and highly hydraulic limes and, perhaps, cement mortars were later employed during operation of renovating and restoring.
CELESTINO GRIFA*, ALESSIO LANGELLA, VINCENZO MORRA and GIANLUCA SORICELLI - "Pantellerian Ware" from Miseno (Campi Flegrei, Naples) Abstract - Samples
of cooking ware from the Sacello degli Augustali, a worship place of the ancient
Misenum, were investigated from an archaeometric point of view. On
typological basis (shape, accurate polished surface, typical volcanic inclusions)
some of them were considered as belonging to the so-called «Pantellerian
Ware». The petrographical and mineralogical study allowed to identify
three groups characterized by different volcanic temper. Six samples instead
of four were attributed to Pantellerian Ware due to the occurrence of phases
typical of magmatic evolved peralkaline rocks. A second group was identified
for the presence of a volcanic temper typical of calcalkaline rocks and tentatively
assigned to an Aeolian provenance. The third group shows abundant trachytic
and leucititic rock fragments and likely represents a local production.
It is remarked the good technological properties of the cooking ware from Pantelleria
due to the use of abundant and well sorted temper, non calcareous clays and
low firing temperatures that provide the manufact a low dilation coefficient
and good resistance to strong thermal shocks. These features along with a well
standardized manufacture that makes these potteries suitable to be transported,
allowed to achieve a large diffusion of the «Pantellerian Ware»
within the Mediterranean Sea, from the African through the Spanish coasts, and
in the Gulf of Naples and Pozzuoli.
Abstract - European non-sulfide Zn deposits, mainly hosted in carbonate rocks and considered so far of supergene origin, represent the historical basis for zinc mining and smelting industry. They were called «Calamine», from the famous Belgian locality where a mixture of Zn-carbonates {smithsonite = ZnCO3, hydrozincite = Zn5(CO3)2 (OH)6, Zn-silicates {hemimorphite = Zn4(Si2O7)(OH)2.H2O, willemite Zn2SiO4} and Zn-clays has been exploited for centuries. A fluid inclusion study has been carried out on Belgian willemite samples, in order to gain information on temperature and salinity of the fluids involved in the formation of the non-sulfide ore deposits. Among all (observed?) inclusions, 80% are monophase (L) and 20% liquid-rich two-phase (L+V). Albeit widespread necking-down and leakage phenomena have affected most of the fluid inclusions trapped, a reliable set of homogenization temperatures, ranging between 80 and 190°C, has been collected from the two-phase inclusions. Tm data suggest salinities between 0 and 5 wt. % NaCl equiv. The detected Th intervals match temperature ranges measured in other willemite ores throughout the world, part of which are considered of hydrothermal origin. These fluid inclusion data pose many questions on the genesis and evolution of Belgium non-sulfide deposits.