Campanian

These studies reported two distinctive events one broadly coeval Turonian to Campanian ( 88-81 Ma) volcanism-sedimentation, and the other, a younger Paleocene ( 64-60 Ma) emptive event. Three different emplacement settings are represented, the combination of which defines a complex kimberlite field characterized by tabular, often stacked kimberlite layers of varying ages (Fig. 2). 

The youngest eruptive event is of Paleocene age ( 60 Ma) whereas the youngest preserved host rocks capping the Buffalo Head Hills are of Campanian age ( 78 Ma). In this instance, the only record of now eroded latest Campanian through Paleocene host rocks is provided by sedimentary xenoliths preserved in the truncated intra-crater facies ultramafic bodies (e.g., K1 body). 

Figure 5. The increase of rank of coal (on the basis of vitrite analyses) towards the magnetic anomaly near Bramsche. kru = Weatden (Lower Cretaceous) kroi = Cenomanian krot = Upper Campanian (Upper Cretaceous). The numbers at the margin of the map indicate the numbers of the single topographic maps 1 25 000...

Figure 6. The doming of the isovols in the roof of the Bramsche Masstf.B borehole cro4 = Upper Campanian (Upper Cretaceous) cro = Upper Cretaceous croi = Cenomanian (Upper Cretaceous) k = Albian (uppermost Lower...

Aiuppa, A., Avino, R., Brusca, L. et al. (2006) Mineral control of arsenic content in thermal waters from volcano-hosted hydrothermal systems Insights from island of Ischia and Phlegrean fields (Campanian volcanic province, Italy). Chemical Geology, 229(4), 313-30. 

This province is characterised by the close association of KS and HKS rocks, showing diverse geochemical and isotopic signatures. Some low-potassium mafic rocks falling in the calc-alkaline compositional field have been also found. Potassic rocks display ratios of some incompatible trace elements such as Ba/La, and radiogenic isotope signatures that are close to those of the Neapolitan volcanoes (Vesuvio, Campi Flegrei, Ischia). On the contrary, ultrapotassic rocks resemble the Colle Albani and other Roman volcanoes. Therefore, the Ernici-Roccamonfina zone is characterised by the coexistence of Roman-type and Campanian-type rocks. 

The Emici and Roccamonfina magmas exhibit peculiar compositional characteristics in terms of their very variable geochemical and isotopic signatures for potassic to ultrapotassic mafic rocks. These are not encountered in other potassic volcanoes of central Italy (i.e. Roman and Campanian provinces, with the possible exception of Vico volcano), where coexisting KS and HKS rocks have different potassium and incompatible trace element abundances but exhibit similar incompatible element ratios and radiogenic isotope signatures (Peccerillo 1999, 2002). 

Volcanic rocks in Campania and Pontine Islands range from mafic to felsic and mostly have silica undersaturated potassic to ultrapotassic compositions (Fig. 6.2). Mafic rocks with K2O contents close to calc-alkaline basalts have been found both as lavas and as lithic ejecta at Ventotene and Procida-Vivara. Pliocene (about 4.5 Ma) calc-alkaline rhyolites occur at Ponza, and 2 Ma old calc-alkaline basalts to andesites have been found by borehole drilling beneath the Campanian Plain north of Campi Flegrei. 

Fig. 6.1. Location map of the Campanian volcanoes, Pontine Islands and Mount Vulture.

Oxygen isotope signatures of Vesuvio rocks show wide variations (S180 —1-7.0 to +10.0) and are negatively correlated with MgO (Ayuso et al. 1998). Helium isotope studies on clinopyroxene and olivine from historical lavas gave values of R/Ra 2.2 to 2.7, close to ratios found in the fumar-oles of Campanian volcanoes (Tedesco et al. 1990 Graham et al. 1993). 

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.

Major elements show a vertical trend for potassium in the mafic rocks (Fig. 6.16c). These have moderate enrichments in incompatible elements, which are lower than in other Campanian volcanoes ferromagnesian trace element contents are high in the mafic rocks (Ni up to 230 ppm, Cr up to 600 ppm). REE are fractionated, with small or no Eu anomalies (Fig. 6.17a). Incompatible element patterns of mafic rocks are fractionated and contain small negative anomalies of HFSE and positive spikes of Pb (Fig. 6.17b). Sr and Nd isotopic ratios respectively display lower and higher... 

The volcanoes in the Campania Province, Pontine Islands and Vulture are composed of a wide variety of magma types. Silica undersaturated ultrapo-tassic volcanism is restricted to Somma-Vesuvio, whereas mildly undersaturated to oversaturated potassic rocks occur at Campi Flegrei, Ischia, Procida and Ventotene. In the latter two islands, low potassium compositions close to calc-alkaline basalts are found among lavas and lithic ejecta. Pliocene calc-alkaline rocks are found as rhyolites at Ponza and as basalts and basaltic andesites beneath the Campanian Plain. At Vulture, volcanism is highly enriched in both Na and K, a composition that is distinct from any other volcano in the Italian peninsula. 

The Vulture, Campania and Pontine volcanoes are characterised by magmas that vary from calc-alkaline to ultrapotassic compositions. Calc-alkaline rocks occur as rhyolites at onza and as basalt to basaltic andesites beneath the Campanian plain. Both these occurrences are older than the potassic and ultrapotassic magmas, indicating an overall time-related increase in potassium on a regional basis. 

At Stromboli, the increase in incompatible element abundances and Sr isotopic ratios from calc-alkaline to potassic suites was suggested by Fran-calanci et al. (1989) to have been generated by a process of continuous fractional crystallisation, assimilation and mixing. However, although this process can be modelled numerically, it fails to explain the geochemical similarity of Stromboli and Campanian volcanoes, as discussed earlier. 

Sr-Nd-Pb isotope variation along the Aeolian arc represents a part of a larger hyperbolic array connecting the Na-alkaline rocks of Etna-Iblei-Ustica and Tuscany (Figs. 7.6, 7.17). Most of the western and central Aeolian islands plot near to the low-Sr, high-Nd-Pb end-member, whereas the Stromboli volcanics plot away from Etna together with Campanian volcanoes and Emici-Roccamonfina KS rocks. However, the isotopically most primitive rocks from Alicudi have low Sr-isotopic ratios that fall outside the trend (Fig. 7.17). 

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