Zr- and LREE-rich Titanite from Tre Croci, Vico Volcanic Complex (Latium, Italy)

G. Della Ventura, F. Bellatreccia and C. T. Williams
Dipartimento di Scienze Geologiche, Università di Roma Tre, Largo S. Leonardo Murialdo 1, 00146 Roma
Department of Mineralogy, The Natural History Museum, Cromwell Road, London SW7 5BD, UK

Abstract: Titanite occurs in the groundmass of a holocrystalline volcanic ejectum collected in the pyroclastic rocks of the Vico Volcanic complex at Tre Croci, near Viterbo, Italy. The host rock is composed of abundant K-feldspar and minor plagioclase, biotite, clinopyroxene and a feldspathoid (sodalite). Titanite is typically associated with zirconolite, biotite and Fe-oxides. It has a medium Al content (Al2O3 + Fe2O3 = 4–6 wt.%) and contains significant amounts of Zr and LREE, with a chondrite-normalised REE pattern similar to those of titanites from other alkaline rocks. Titanite has been corroded by fluids probably rich in dissolved F and P during a late alteration stage, with evidence for some remobilization and redistribution of the REE and actinide elements.

Keywords: Vico volcanic complex • titanite • chemistry • REE patterns • alteration

Mineralogical Magazine; February 1999 v. 63; no. 1; p. 123-130; DOI: 10.1180/002646199548240
© 1999, The Mineralogical Society
Mineralogical Society (www.minersoc.org)