Rb-Sr AND U-Pb AGE DETERMINATIONS ON THE PEGMATITE OF I MONDEI (PENNINIC CAMUGHERA-MONCUCCO-COMPLEX, ITALIAN ALPS AND SOME GNEISSES FROM THE NEIGHBORHOOD)

Journal Article · Sat Dec 01 04:00:00 EST 1962 · Eclogae Geologicae Helvetiae (Switzerland)

OSTI ID:4160377

Ferrara, G; Hirt, B; Jaeger, E; Niggli, E

Results are given concerning the formation of the Camughera-Moncucco complex (Val d'Ossola, Northern ltaly). Large crystals of Muscovite from a beryl pegmatite from the cava di mica I Mondei and biotite samples and muscovite samples of gneisses of the neighborhoods were measured with the Rb/Sr method. On the pegmatite, traces of the alpine metamorphism are evident. Biotites give quite young ages (18-26 MY); those of muscovites are a little higher (32 MY). Results obtained on muscovites samples from the pegmatite 1200 MY) show that the muscovites with large crystals retain their radiogenic strontium even if undergone to a metamorphic action. Samples of uraninite coming from the pegmatite were also measured. Results (140-170 MY) show a loss of Pb. It was concluded that beryl pegmatite from I Mondei intruded in a pre-tertiary time. (auth)

• Research Organization: CNEN, Pisa, Italy
• NSA Number: NSA-18-000420
• OSTI ID: 4160377
• Journal Information: Eclogae Geologicae Helvetiae (Switzerland), Journal Name: Eclogae Geologicae Helvetiae (Switzerland) Vol. Vol: 55; ISSN EGHVA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

AGE ESTIMATION
ALUMINUM SILICATES
BERYLLIUM SILICATES
CRYSTALS
GEOLOGY AND MINERALOGY
GNEISS
LEAD
PEGMATITES
POTASSIUM SILICATES
QUANTITATIVE ANALYSIS
ROCKS
RUBIDIUM
STRONTIUM
STRONTIUM ISOTOPES
URANINITES
URANIUM