Neapolitan Yellow Tuff

Fig. 6.10. TAS classification diagram for Campi Flegrei and for buried Pliocene rocks beneath Campi Flegrei (Parete-2 well). Circled fields indicate compositions of the Campanian Ignimbrite (Cl) and Neapolitan Yellow Tuff (NYT) pumices.

Pappalardo L, Civetta L, D Antonio M, Deino A, Di Vito MA, Orsi G, Caran-dente A, De Vita S, Isaia R, Piochi M (1999) Chemical and isotopical evolution of the Phlegraean magmatic system before the Campanian Ignimbrite (37 ka) and the Neapolitan Yellow Tuff (12 ka) eruptions. J Volcanol Geotherm Res 91 141-166... 

The plots confirm the existence of a contamination characterized by isotopic values very similar to those of the soils (i.e., the natural values). Plots of the isotopic ratios (207/20/ Pb vs. 208/20/ Pb) show two distribution trends that converge toward values typical of the Neapolitan Yellow Tuff (D Antonio el al, 1995) (Fig. 15.10). 

The early discovered sedimentary zeolite deposits, during the 1950s, were the Green tuff formation of Yokolemachi, Akira Prefecture, Japan, [18], the low-grade metamorphic rocks of Southland, New Zealand [19], and the Neapolitan yellow tuff, around Naples, Italy [20], Many zeolite occurrences were made known a few years later in the western USA, as a result of a capillary five-year exploration campaign promoted by Union Carbide and other chemical companies [21]. After these, hundreds of zeolite formations were and are being discovered in many countries around the world. 

Fig. 2. Phillipsite crystals, (a) macrocrystals of hydrothermal origin (sample from Collezione Vesuviana, Arcangelo Scacchi hall, Real Mineralogical Museum, Naples, Italy) (b) microcrystals of sedimentary origin covering a pumice wall in Neapolitan yellow tuff (sample from Rione Sanita, Naples, Italy) (SEM, Oxford-Cambridge S440)...

The interaction of zeolite-rich materials with Ca(OH)2 is of special interest, because zeolites, like other reactive aluminosilicate systems, e.g., crushed bricks, give rise to calcium silicates and aluminates, which are able to harden upon hydration in both aerial and aqueous environments. This behaviour, already known in ancient times, is typical of a volcanic, mostly glassy material, called pozzolana, which is the genetic precursor of the mentioned Neapolitan yellow tuff, widely spread in the surroundings of Naples, Italy [61]. That is why every material able to behave as pozzolana is called "pozzolanic material" and the property to react with lime is called "pozzolanic activity". 

Fixed-bed ion-exchange process performance of removal from a simulated ceramic wastewater by Neapolitan yellow tuff... 

A phillipsite-rich Neapolitan yellow tuff bed, pre-exchanged in Na form, was used to remove PV from a simulated wastewater of a ceramic manufacture through cation-exchange in dynamic conditions. The composition of the simulated wastewater was the following Pb 22 mg/1 Na 110 M K ", 1 10- M Ca ... 

The phillipsite-rich tuff sample came from a quarry in Chiaiano (Naples, Italy), belonging to the huge formation of Neapolitan Yellow Tuff (NYT) spread over a vast area NW of Naples, called Campi Flegrei [12]. 

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