|
|
|
|||||||||||||||||
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
1 Dipartimento di Scienze della Terra, Università G.dAnnunzio, Chieti, Italy
2 Department of Mineralogy, Natural History Museum, Cromwell Road, London SW7 5BD, UK
3 Dipartimento di Geofisica e Vulcanologia, Università Federico II, Napoli, Italy
* E-mail: fstoppa{at}unich.it
A new occurrence of a rare kamafugite near LAquila, 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, haüyne, 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 Sahamas (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
This article has been cited by other articles:
![]() |
F. Stoppa, G. Rosatelli, A. Cundari, F. Castorina, and A. R. Woolley COMMENT ON MELLUSO ET AL. (2003): Reported data and interpretation of some wollastonite- and melilite-bearing rocks from the Central Apennines of Italy American Mineralogist, November 1, 2005; 90(11-12): 1919 - 1925. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Di Muro, E. Bonaccorsi, and C. Principe Complex colour and chemical zoning of sodalite-group phases in a hauynophyre lava from Mt. Vulture, Italy Mineralogical Magazine, August 1, 2004; 68(4): 591 - 614. [Abstract] [Full Text] [PDF] |
||||
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |