When detection and quantification of mineral fibres in natural raw materials are at their limit-the case of a clay from the Gomsiqe-Puka mining area (Albania)

In today's global market, the movement of raw materials and goods in the free global market can lead to unintended consequences. One significant concern is the potential presence of contaminants and carcinogens, particularly when products originate from regions with less strict regulations and enforcement. This issue is particularly pertinent in the natural raw materials utilized in the global building materials market, where contamination by asbestos minerals can occur. Therefore, the screening of natural raw materials for asbestos content is crucial to mitigate the risk of exposure to carcinogens for both workers and the general public. In this study, we examine a challenging case involving a smectite-kaolinite clay from Gomsiqe-Puka, Albania, possibly containing mineral fibres. Detection and quantification of asbestos in this material push the boundaries of current experimental methods. Using transmission electron microscopy (TEM), micro-Raman spectroscopy, and electron probe microanalysis (EPMA), we identified the presence of asbestos tremolite, along with a rare fibrous variety of diopside. EPMA data allowed the advancement of some speculations on the origin of the observed tremolites, showing that Al-rich tremolites are typical of oceanic settings and Al-poor tremolites are more similar to continental tremolites.We also investigated the impact of milling on the detection and quantification of mineral fibres, testing different milling times. This investigation is crucial as it can influence the classification of the raw material as asbestos-containing material or not. Our findings indicate that tremolite, cleavage fragments, and elongated particles break down into smaller World Health Organization (WHO) fibres with increasing milling times (1-5 min). However, prolonged milling (10 min) leads to overgrinding, resulting in a decrease in the number of counted WHO fibres with a length exceeding 5 mu m

Risalita di fluidi freddi ricchi in metano, carbonati autigeni ed instabilità sedimentaria nel Miocene medio-superiore dell’Appennino settentrionale.

Negli ultimi decenni numerose ricerche hanno evidenziato che le risalite di fluidi sui fondali oceanici, sia calde che fredde, sono fenomeni globalmente estesi, con importanti implicazioni geologiche e biologiche. La risalita di fluidi è generalmente connessa con: a) precipitazione di minerali autigeni fra cui carbonati primari (calcite, aragonite e dolomite), solfuri e solfati; b) peculiari caratteristiche geochimiche dei sedimenti, delle rocce, dell’acqua e degli organismi; c) l’instaurarsi di relazioni simbiotiche fra comunità macrofaunali e microrganismi; d) la formazione di processi diapirici con caoticizzazione dei sedimenti incassanti; e) processi d’instabilità sedimentaria (frane sottomarine di varia tipologia).Verso la fine degli anni ‘70 lo studio dei fondali oceanici, con l’impulso prodotto dall’utilizzo di sottomarini, ha permesso la scoperta dell’esistenza di risalite di fluidi idrotermali arricchiti in solfuri (hot vents) caratterizzati dalla strutturazione di camini costituiti principalmente da solfuri e dalla presenza di una peculiare ed abbondante fauna chemiosintetica (Lonsdale, 1977).A partire dagli anni ‘80, il proseguire delle indagini sottomarine ha evidenziato l’esistenza di risalite localizzate di fluidi freddi ricchi in idrocarburi leggeri (cold seeps), diffusi praticamente in tutti i contesti geodinamici oceanici: nei margini attivi sono segnalati nel prisma di accrezione dell’Oregon (Ritger et al., 1987; Bohrmann et al., 1998), del Giappone (Sakai et al, 1992), del Makran (Von Rad et al, 1996), del Perù (Sample, 1996), di Barbados (Lance et al, 1998), delle Aleutine (Suess et al, 1999) e del Mediterraneo orientale (Aloisi et al, 2000), nel Mar Nero (Peckmann et al., 2001), nel mare marginale di Okhotsk (Esikov and Pashkina, 1990; Greinert, 1999), nel bacino di avanarco della Sonda (Wiedicke et al, 2002), nella scarpata continentale della Nuova Zelanda (Lewis & Marshall, 1996). Nei margini passivi sono frequenti nel Mare del Nord (Hovland et al., 1987), al largo della Danimarca (Jorgensen, 1992), alla base della scarpata a gradoni della Florida (Paull et al., 1995), nel Golfo del Messico (Roberts, 2001). Sono presenti infine nei margini trascorrenti-conservativi della California (Embley et al, 1990; Stakes et al, 1999).Come già osservato per gli hot vents, i cold seeps sono caratterizzati dalla presenza di una fauna bentonica rigogliosa, sostenuta su base chemiosintetica. Si formano comunità a bivalvi in endosimbiosi con batteri solfo-ossidanti, solfato-riducenti e metano-ossidanti (Van Dover, 2000). I batteri utilizzano energia chimica al posto della luce solare e trasformano composti inorganici in sostanze utilizzabili dai bivalvi; viceversa questi ultimi forniscono protezione ai batteri. In corrispondenza dei cold seeps si può realizzare la precipitazione di carbonati autigeni, che sono stati riconosciuti nel record geologico a partire almeno del Fanerozoico (Barbieri et al. 2001; Campbell et al, 2002, Campbell, 2006 e riferimenti bibliografici in essi contenuti). E’ ampiamente riconosciuto che i migliori indicatori di prodotti fossili di cold seeps sono: a) forte impoverimento in 13C dei carbonati, con conseguenti valori isotopici negativi del δ13C; b) associazioni di macrofauna particolare e oligotipica; c) biomarkers specifici (Campbell and Bottjer, 1993; Aharon et al, 1992; Aharon, 2000; Taviani, 2001; Peckmann et al, 2001, 2002; Campbell et al, 2002); d) peculiari strutture riconducibili a fenomeni diapirici.Interessanti esempi fossili di cold seeps sono rappresentati dal “calcare a Lucina” dell’Appennino settentrionale, oggetto della presente escursione. Questi carbonati, caratterizzati da una composizione isotopica negativa del carbonio e da una consistente presenza di fossili di bivalvi (principalmente lucinidi di grandi dimensioni), sono testimonianza di una lunga e complessa storia di risalita di fluidi arricchiti in metano perdurata durante la strutturazione della catena appenninica nel tardo Terziario. Il “calcare a Lucina” è conosciuto e studiato a partire dalla seconda metà dell’800, ed ha suscitato interesse per l’ampia diffusione degli affioramenti, dal Monferrato alla Sicilia e perché si riteneva che la specie Lucina Pomum fosse un fossile guida del Miocene Medio (per i riferimenti storici vedere Conti et al, 1996; Ricci Lucchi and Vai, 1994; Taviani, 2001). A partire dall’inizio del ‘900 l’importanza stratigrafica della specie L. Pomum venne confutata in quanto risultava evidente che il genere Lucina affiorava nei terreni miocenici di tutte le età; rimase tuttavia la convinzione che fosse un buon fossile di facies, indicatore di acque poco profonde. Successivamente, il riconoscimento che alcuni depositi contenenti il genere Lucina sono in realtà risedimentati ne ha rinnovato l'interesse in quanto ritenuti indicatori di fenomeni d'instabilità nell'avanfossa appenninica.I depositi calcarei a Lucina sono stati recentemente reinterpretati come il prodotto fossile degli attuali cold seeps, a partire dagli studi di Clari et al (1988) sui “calcari Marmorito” del Piemonte. In seguito questa interpretazione è stata estesa ad altri affioramenti dell’Appennino settentrionale (Ricci Lucchi and Vai, 1994; Clari et al, 1994; Berti et al, 1994; Terzi et al, 1994; Taviani, 1994, 1996, 2001; Conti et al, 1996; Cavagna et al, 1999; Conti and Fontana, 1999, 2002; Barbieri et al, 2000, 2001; Peckmann et al, 2001). Questi studi hanno evidenziato che il “calcare a Lucina” è uno fra i migliori esempi di prodotti fossili collegati a risalite di fluidi freddi, comparabile ad altre situazioni descritte per il Mesozoico ed il Terziario del Giappone e del margine convergente del Pacifico nordorientale (Campbell and Bottjer, 1993; Shibasaki and Majima, 1997; Campbell et al, 2002; Peckmann et al, 2002)

Sedimentology and composition of sands injected during the seismic crisis of May 2012 (Emilia, Italy): Clues for source layer identification and liquefaction regime

In May 2012 widespread sand blows formed along buried channels in the eastern sector of the Po Plain as a consequence of a seismic crisis with main shocks of Mw 6.1 and 5.9. At San Carlo (Ferrara) a trench dug a few week after the earthquakes exposed sand dikes cutting through an old Reno River channel-levee system that was diverted in the 18° century and was deposited starting from the 14° century (unit A); this sequence lie on Holocene muddy floodplain and scattered sandy channel deposits (unit B) and a Pleistocene channel sand unit (unit C). Sand inverse and direct grading, concave layering and vertical lamination coexisting along the dikes suggest multiple rhythmic opening and closing of the fracture borders that were injected and filled of slurry sand during the compression pulses end emptied during the extension phase. The pulse mechanism may have lasted for several minutes and formed well stratified structure of the sand volcanoes that formed on the top of some fractures. Sands from dikes and from the various units show well defined compositional fields from lithoarenitic to quartz-feldspar-rich compositions. Sorting related to sediment flux variations did not apparently affect the sand composition, across the sedimentary structures. Sands from the old Reno levee and channel fill (unit A) have abundant lithic fragments deriving from the erosion of Apennine sedimentary carbonate and terrigenous successions. Pleistocenic sands (unit C) are enriched in quartz and feldspars as a consequence of the different climatic weathering condition that prevailed during the last glacial stage. The Pleistocene sand were partially reworked during the Holocene (unit B). Composition of the sand filling the dikes show clear affinities with sand layer of the old Reno River channel (Unit A) and clearly differ from any sand from deeper layers (Unit B and C), which are richer in quartz and feldspar and poorer in sedimentary lithic fragments. Textural and compositional data indicate that the liquefaction processes originated from a relatively shallow source consisting of channel sands located within Unit A at 6.8.to 7.5 m depth

Composition of sands injected during the seismic crisis of May 2012 at San Carlo, Ferrara (Italy)

In May 2012 widespread sand blows formed along buried channels in the eastern sector of the Po Plain as a consequence of a seismic crisis with main shocks of Mw 6.1 and 5.9. At San Carlo (Ferrara) a trench dug a few week after the earthquakes exposed sand dikes cutting through an old Reno River channel-levee system that was diverted in the 18° century and was deposited starting from the 14° century (unit A); this sequence lie on Holocene muddy floodplain and scattered sandy channel deposits (unit B) and a Pleistocene channel sand unit (unit C). Sand inverse and direct grading, concave layering and vertical lamination coexisting along the dikes suggest multiple rhythmic opening and closing of the fracture borders that were injected and filled of slurry sand during the compression pulses end emptied during the extension phase. The pulse mechanism may have lasted for several minutes and formed well stratified structure of the sand volcanoes that formed on the top of some fractures. Sands from dikes and from the various units show well defined compositional fields from lithoarenitic to quartz-feldspar-rich compositions. Sorting related to sediment flux variations did not apparently affect the sand composition, across the sedimentary structures. Sands from the old Reno levee and channel fill (unit A) have abundant lithic fragments deriving from the erosion of Apennine sedimentary carbonate and terrigenous successions. Pleistocenic sands (unit C) are enriched in quartz and feldspars as a consequence of the different climatic weathering condition that prevailed during the last glacial stage. The Pleistocene sand were partially reworked during the Holocene (unit B). Composition of the sand filling the dikes show clear affinities with sand layer of the old Reno River channel (Unit A) and clearly differ from any sand from deeper layers (Unit B and C), which are richer in quartz and feldspar and poorer in sedimentary lithic fragments. Textural and compositional data indicate that the liquefaction processes originated from a relatively shallow source consisting of channel sands located within Unit A at 6.8.to 7.5 m depth

Progress in mineralogical quantitative analysis of rock samples: Application to quartzites from Denali National Park, Alaska Range (USA)

This work deals with the determination of the mineralogical composition of three quartzite samples, selected as case study to verify the viability and accuracy of various experimental techniques commonly used in geometallurgy and petrography for the determination of the mineralogical composition of rock samples. The investigated samples are from the North-Eastern side of the Denali National Park (Alaska Range, USA). The mineralogical phase abundance of the samples was determined by digitally assisted optical modal point counting, scanning electron microscopy (SEM) + energy dispersive spectroscopy (EDS) modal and digital image analysis, normative calculation from bulk chemistry calculation, and modal Rietveld X-ray powder diffraction. The results of our study indicate that the results provided by modal optical and SEM digitalized counting seem less accurate than the others. The determination with EDS mapping was found to be inaccurate only for one sample. Agreement was found between the X-ray diffraction estimates and bulk chemistry calculation. For both modal optical and SEM digitalized counting, the statistics was probably insufficient to provide accurate results. The estimates obtained from the various methods are compared with each other in the attempt to attain general indications on the precision, accuracy, advantages/disadvantages of each method

I materiali da costruzione nell'interno della torre: le pietre, i mattoni, le malte, gli intonaci

Il rilievo del paramento esterno delle torre ha permesso di individuare le fonti di approvvigionamento dei materiali lapidei e di fornire indicazioni sulle fasi costruttive (Lugli et al., 2009). Un contributo fondamentale alla lettura del monumento viene dallo studio integrato della struttura interna e dei materiali che la compongono: le pietre naturali, i mattoni le malte e gli intonaci. Il rilievo dei parametri dimensionali dei mattoni permette di individuare l\u2019entit\ue0 del reimpiego di laterizi provenienti da antichi edifici e le caratteristiche dei prodotti di nuova preparazione. L\u2019analisi composizionale delle malte e degli intonaci permette di ottenere informazioni sulle tecniche di preparazione e la loro evoluzione nel tempo per effettuare un tentativo di datazione indiretta delle fasi costruttive. Vengono inoltre individuate le fonti di approvvigionamento delle materie prime (calce e sabbia) fornendo indicazioni indispensabili sulla preparazione di malte e intonaci da impiegare nelle operazioni di restauro

Archaeometrical investigations of impasto pottery from Terramara of Gorzano (Modena, Italy)

Il contributo è dedicato all'approccio archeometrico relativamente a ceramiche di impasto dell'età del bronzo delle terramare, con particolare riguardo a quelle provenienti dalla terramara di Gorzano (Modena)Bronze Age Impasto pottery from Gorzano Terramara was analysed to identify raw materials and manufacturing techniques. Impasto ceramic paste is a heterogeneous mixture of fine sediments and tempers. Ceramics and sediments surrounding the site were characterised through petrographic analysis, chemical analysis of major, minor and trace elements and X-ray powder diffraction. The results show that the fine fraction of the pottery is low in carbonates, while most sediments are calcareous and show different clay mineral/carbonate ratios. Only three sediment samples of the Niviano unit are chemically and mineralogically similar to the fine fraction of the pottery. However the higher concentration of Al2O3 in the pottery suggests the use of a raw material richer in clay minerals and hence the possibility that sediment from the Niviano unit were partially levigated before use

Bronze Age Terramare pottery from Northern Italy – exercises in experimental reproduction

Bronze age pottery from Montale Terramara was reproduced to investigate the specialization degree of manufacturing craft. The technique (coiling or moulds) and the raw materials (local clay tempered with grog) were investigated in a previous achaeometric research. 20 pots of various shapes (cup, bowl, pithos and jar) were reproduced by three professional potter in the archaeological park of Montale, formed with coilings and moulds and fired in a traditional kiln (reproduction of a Bronze Age kiln from the area). During the manufacturing process the time and the technical – artistic difficulty were recorded. The results helps to define the manufacturing process of the different shapes in the various phases, and contribute to the discussion of the craft specialization: five groups of pots have been classified corresponding to an increasing specialization degree