Authigenic monazite and xenotime from pelitic metacherts in pumpellyite-actinolite-facies conditions, Sestri-Voltaggio Zone, central Liguria, Italy

Monazite-(Ce) and xenotime-(Y) were found in the metacherts (pumpellyite-ac tinolite-facies conditions: 3 less than or equal to P less than or equal to 4 kbars and 300 less than or equal to T less than or equal to 350 degreesC ) of the Monte Figogna Unit, Sestri-Voltaggio Zone, Liguria, in Italy, as s cattered submillimetric grains in pelitic beds and as euhedral crystals in both millimeter-thick quartz veins and open fissures. Their composition is comparable to those of known occurrences in metapelites from greenschist-fa cies conditions, The textural evidence points to a synmetamorphic authigeni c origin of these phases related to local mobilization and reconcentration of the REE during the metamorphic recrystallization of the clay fraction.