Roman Province

Geld, iron, and lead were procured in the South, and soma tin in the North of Spain but the gold was probably of small amount, and silver was the chief mineral wealth of the country. Of this mineral Pliky says it was found in all tho Roman provinces, but the best in Spain, and that in a barren soil, even in the... 

Roman Province (Latium) (0.8 to 0.02 Ma) Vulsini (0.6-0.15), Vico (0.4-0.1), Sabatini (0.8-0.04), Colli Albani (0.6-0.02) - Large volcanic complexes formed of potassic (trachybasalt to trachyte) and ultrapotassic (leucite tephrite, to phonolite) pyroclastics and minor lavas. 

This is part of the belt of potassic and ultrapotassic rocks running from northern Latium to the Neapolitan area, which was defined as the Roman Comagmatic Region by Washington (1906). The Roman Province (or... 

Fig. 3.4. Chondrite normalised REE patterns and mantle normalised incompatible element patterns of Intra-Apennine volcanic rocks. Patterns for mafic rocks from the Roman Province and the Virunga volcanoes (East Africa), for Enriched Mid Ocean Ridge Basalts (E-MORB) and for limestones from northern Apennines are also shown.

HFSE (Bosi and Locardi 1992). These characteristics are common to both the IAP and Roman Province, and do not allow the exclusion of a provenance from Roman volcanoes for the most fine-grained deposits. 

Petrologically, Roman Province volcanic rocks are mostly ultrapotassic and undersaturated in silica, but saturated to oversaturated potassic rocks... 

Fig. 4.1. 1 Location map of volcanoes of the Roman Province. Inset schematic structural map of northern Apennines.

The volcanoes of the Roman Province developed in a region characterised by Late Miocene-Quaternary extensional tectonics related to the eastward migration of Apennine mountain range and to the contemporaneous opening of the Tyrrhenian Sea. The volcanic zone is characterised by a system of Upper Miocene to Pleistocene NW-SE basins, developed along normal faults and intersected by strike-slip NE-SW faults (Bartolini et al. 1982). Both fault systems represent zones of crustal weakness along which Roman potassic magmas were intruded. 

The Roman Province is characterised by less than 25 km thick crust (Pi-romallo and Morelli 2003) and by anomalous heat flow of more than 100 mWm"2 at a regional scale (Mongelli and Zito 1991 Mongelli et al. 1991),... 

Table 4.1. Petrological-volcanological characteristics and ages of volcanoes in the Roman Province. ...

Fig. 4.9. Sr vs. Nd isotope diagram for the volcanic rocks of the Roman Province. Compositions of other provinces are reported for comparison.

Variation diagrams of major and trace elements vs. MgO at Colli Albani (Fig. 4.19) show a positive correlation for CaO, TiC>2, FeOtotai and ferro-magnesian trace elements (Cr, Ni, Co, etc.), negative correlations for Na20, K2O, AI2O3 and incompatible elements (Th, La, Ta, etc.), and a bell shaped trend for P2O5. Incompatible elements show smooth inter-element positive trends (Fig. 4.19g). The pre-caldera lavas seem to define different trends on some major and trace element variation diagrams, especially on plots of incompatible element vs. incompatible element ratios (Fig. 4.19h). REE and incompatible element patterns have shapes that are similar to those for other ultrapotassic rocks from the Roman Province (Fig. 4.20). 

Interaction between magma and wall rocks has been a common process in the Roman Province. However, the core problem is the question of how much this interaction has modified the pristine compositional characteristics of the mafic parent magmas. A particularly important issue is whether the crustal-like geochemical and isotopic signatures of Roman mafic vol-canics can be explained solely by some form of crustal assimilation. These problems have been discussed at length not only for the Roman Province but for all the potassic volcanoes occurring across the Italian peninsula and in the Aeolian arc. 

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