Extension of the melilite-carbonatite province in the Apennines of Italy: the kamafugite of Grotta del Cervo, Abruzzo F. STOPPA 1, *, A. R. WOOLLEY 2 AND A. CUNDARI 3 1 Dipartimento di Scienze della Terra, Universita ` G.d’Annunzio, Chieti, Italy 2 Department of Mineralogy, Natural History Museum, Cromwell Road, London SW7 5BD, UK 3 Dipartimento di Geofisica e Vulcanologia, Universita ` Federico II, Napoli, Italy ABSTRACT A new occurrence of a rare kamafugite near L’Aquila, Abruzzo, is described in detail to characterize its paragenesis and to establish possible genetic links with similar alkaline mafic igneous rocks from the Oricola-Camerata Nuova (OC) volcanic field, ~20 km to the west. Both occurrences belong to the Umbria-Latium-Ultralkaline-District (ULUD), an igneous district represented by rare kamafugites and carbonatites and distinct from the much more voluminous Roman Region (RR) rocks. The new kamafugite was found in a cave known as Grotta del Cervo (GC), associated with epiclastic and pyroclastic rocks. In the latter, lapilli ash tuff, welded lapilli, ultramafic xenoliths, cognate lithics and pelletal lapilli have been identified. The mineralogy of the welded lapilli comprises, in order of decreasing abundance, diopside, leucite, hau ¨yne, Mg-mica, andraditic garnet, apatite, magnetite, kalsilite and olivine. The rock is carbonate-free. Based on bulk-rock chemistry it is classified as a kamafugite, closely approaching the composition of ULUD kamafugites, according to Sahama’s (1974) criteria. Separate lapilli ash tuff, characterized by the same silicate mineralogy as that of the welded lapilli, plus modal carbonate exceeding 10 wt.%, is classified as a carbonatitic kamafugite. Bulk-rock and trace-element compositions confirm that the Grotta del Cervo rocks closely approach the ULUD analogues. The Grotta del Cervo occurrence partially fills the geographical and compositional gap between ULUD rocks and the rocks from the Vulture Complex, also a carbonatite and melilitite locality ~200 km south of GC, and adds considerably to the bulk of kamafugitic and related rocks lying along the Italian Apennines. The petrogenesis of these kamafugites rocks is discussed and possible mineralogical similarities with the Roman Region rocks are highlighted. KEYWORDS: kamafugite, carbonatite, Central Italy, extensional tectonics. Introduction LYING to the east of the volcanic rocks of the Roman Region of central Italy are a number of minor intrusions, diatremes and small volcanoes that form the Umbria-Latium ultra-alkaline district (ULUD) (Lavecchia and Stoppa, 1992). The ULUD rocks differ markedly in their petrology from those of the much more volumi- nous Roman Region and include melilite-bearing rocks, including the rare kamafugites, and five occurrences of extrusive carbonatite. Stoppa and Woolley (1997) demonstrated that another Italian carbonatite occurrence at Vulture is close in composition to the ULUD occurrences. Therefore, Vulture+ULUD may be considered as a single, consanguineous petrographic province. The lateral extent of this province is ~350 km, but there is a gap of ~200 km between the most southerly ULUD occurrences and Vulture. Two new occurrences at the southern end of ULUD have been discovered, namely at Grotta del Cervo (GC) and in the Oricola-Camerata Nuova (OC) area (Fig. 1). The GC rocks are kamafugites s.s., whereas OC rocks comprise carbonatites and foidites. These new occurrences enable significant # 2002 The Mineralogical Society * E-mail: fstoppa@unich.it DOI: 10.1180/0026461026640049 Mineralogical Magazine, August 2002, Vol. 66(4), pp. 555–574