Production of metaluminous melt during fluid-present anatexis: an example from the Maghrebian basement, La Galite Archipelago, central Mediterranean

Garnet brought to the surface by late Miocene granitoids at La Galite Archipelago (Central Mediterranean, Tunisia) contains abundant primary melt and fluid inclusions. Microstructural observations and mineral chemistry define the host garnet as a peritectic phase produced by biotite incongruent melting at ~800 °C and 0.5 GPa, under fluid-present conditions. The trapped melt is leucogranitic with an unexpected metaluminous and almost peralkaline character. Fluid inclusions are one phase at room temperature, and contain a CO2-dominated fluid, with minor H2O, N2 and CH4. Siderite and an OH-bearing phase were identified by Raman and IR spectroscopy within every analysed inclusion, and are interpreted as products of a post-entrapment carbonation/hydration reaction between the fluid and the host during cooling. The fluid present during anatexis is therefore inferred to have been originally richer in both H2O and CO2. The production of anatectic melt with a metaluminous signature can be explained as the result of partial melting of relatively Al-poor protoliths assisted by CO2- rich fluids

Production of metaluminous melt during fluid-present anatexis: an example from the Maghrebian basement, La Galite Archipelago, central Mediterranean

Garnet brought to the surface by late Miocene granitoids at La Galite Archipelago (Central Mediterranean, Tunisia) contains abundant primary melt and fluid inclusions. Microstructural observations and mineral chemistry define the host garnet as a peritectic phase produced by biotite incongruent melting at ~800 \ub0C and 0.5 GPa, under fluid-present conditions. The trapped melt is leucogranitic with an unexpected metaluminous and almost peralkaline character. Fluid inclusions are one phase at room temperature, and contain a CO2-dominated fluid, with minor H2O, N2 and CH4. Siderite and an OH-bearing phase were identified by Raman and IR spectroscopy within every analysed inclusion, and are interpreted as products of a post-entrapment carbonation/hydration reaction between the fluid and the host during cooling. The fluid present during anatexis is therefore inferred to have been originally richer in both H2O and CO2. The production of anatectic melt with a metaluminous signature can be explained as the result of partial melting of relatively Al-poor protoliths assisted by CO2- rich fluids

Beni M'hira: a new chondritic (L6) meteorite fall from Tunisia

The Beni M’hira meteorite fell on January 8, 2001 in southeastern Tunisia. This is only the fifth observed fall from Tunisia. On the basis of mineralogical, petrographic, and geochemical data, the stone can be classified as an L6 chondrite of shock stage S5

Meteorite finds from southern Tunisia

View references (6) We report on the meteorite search campaign of April 2008, conducted by a joint Tunisian- Italian scientific expedition in southern Tunisia (Dahar region). Nine likely unpaired meteorites (seven H-class and two L-class chondrites) totalling ∼1.3 kg were recovered by exploring an approximately 45 km2 area, therefore demonstrating that southern Tunisia is a suitable terrain for systematic searches for meteorites

Archaeometric study of African Keay 25.2 amphorae in Catalonia (Spain): a history of importation and imitation

This work presents the results of archaeometric study of Keay 25.2 amphorae from some sites along the Catalan coast (the ancient Roman province of Hispania Tarraconensis, north-eastern Spain), considered to be vessels imported from production centres in Tunisia and, on the basis of the similarity of macrofabric and shape, in particular from the Sidi Zahruni production area (NE Tunisia). A series of 38 amphorae were analysed by thin-section petrography, X-ray powder diffraction and X-ray \ufb02uorescence. The chemical data were statistically treated in order to de\ufb01ne, for comparison with an established reference group of amphorae from Sidi Zahruni, possible cases of exportation from the Tunisian site to Spain. Many petrographic and chemical groups were identi\ufb01ed among the amphorae, and only some of them turned out to come from the North African production centres, mostly Sidi Zahruni. However, some were characterised by metamorphic and igneous inclusions, which are not consistent with the geology of Tunisia, indicating that they had been produced in other areas of the Roman Empire. The petrographic, mineralogical and geochemical af\ufb01nities of these specimens with Early Roman Catalan amphorae indicate that these Keay 25.2 amphorae were produced in Catalonia, perhaps as imitation products. Identi\ufb01cation of imported specimens and also of local imitations contributed to improving our knowledge of economic relations and trade between Northern Africa and Hispania

Provenance and reference groups of African Red Slip ware based on statistical analysis of chemical data and REE

African Red Slip (ARS) ware (sigillata africana) from three archaeological sites in northern (Oudhna, Sidi Khalifa) and central Tunisia (Henchir el Guellel) was studied by X-ray fluorescence and statistical treatment of chemical data in order to define homogeneous reference groups. The specimens from Henchir el Guellel are clearly different from those of the other two sites, which are compositionally more similar, due to their geographical vicinity. ARS ware from Sidi Khalifa is chemically very homogeneous, whereas that from Oudhna clusters into two distinct groups. The chemical correspondence with literature reference groups, based on both kiln wastes and sherds from archaeological surveys, defines new reference groups, statistically more numerous and representative. Comparisons of chemical data by neutron activation analysis on selected potsherds and clays from the surroundings of each site also identified the probable base-clays used to produce the ARS ware of Oudhna, Sidi Khalifa, and to advance some hypothesis on that used in Henchir el Guellel, thereby overcoming difficulties in assessing chemical contents of elements due to levigation processes

Establishing a new reference group of Keay 25.2 amphorae from Sidi Zahruni (Nabeul, Tunisia)

This paper presents the results of the archaeometric study of African Keay 25.2 amphorae from the archaeological site of Sidi Zahruni (Beni Khiar, NE Tunisia), where this pottery was massively produced. A set of 43 amphorae was analysed with a combined approach consisting of thin-section petrography, X-ray powder diffraction (XRPD) and X-ray fluorescence (XRF), to establish a homogeneous reference group for this production. Although all the amphorae are petrographically very similar, three petro-fabrics were identified in terms of grain-size distribution and abundance of inclusions. Detailed digital image analysis, carried out on SEM-BSE images of some representative samples of each petro-fabric, was used to quantify the differences among them. Cluster analysis of XRPD data patterns also revealed groups of samples forwhich similar rawmaterials/paste and firing conditions were used, contributing to better assessment of information on the production process. Statistical multivariate treatment (principal component and cluster analyses) of chemical data and comparisons with 10 samples previously attributed to the Sidi Zahruni potteries show that the potsherds analysed here are similar from the geochemical viewpoint. Similar trends in the abundance and ratio of some trace and rare earth elements (REE) also indicate that the Sidi Zahruni amphorae were produced from a local clayey material collected from nearby outcrops of Upper Miocene deposits

Establishing a new reference group of Keay 25.2 amphorae from Sidi Zahruni (Nabeul, Tunisia)

This paper presents the results of the archaeometric study of African Keay 25.2amphorae fromthe archaeological site of Sidi Zahruni (Beni Khiar, NE Tunisia), where this pottery was massively produced. A set of 43 amphorae was analysed with a combined approach consisting of thin-section petrography, X-ray powder diffraction (XRPD) and X-ray fluorescence (XRF), to establish a homogeneous reference group for this production. Although all the amphorae are petrographically very similar, three petro-fabrics were identified in terms of grain-size distribution and abundance of inclusions. Detailed digital image analysis, carried out on SEM-BSE images of some representative samples of each petro-fabric, was used to quantify the differences among them. Cluster analysis of XRPD data patterns also revealed groups of samples forwhich similar rawmaterials/paste and firing conditions were used, contributing to better assessment of information on the production process. Statistical multivariate treatment (principal component and cluster analyses) of chemical data and comparisons with 10 samples previously attributed to the Sidi Zahruni potteries show that the potsherds analysed here are similar from the geochemical viewpoint. Similar trends in the abundance and ratio of some trace and rare earth elements (REE) also indicate that the Sidi Zahruni amphorae were produced from a local clayey material collected from nearby outcrops of Upper Miocene deposits