Volcanic products of Lipari (Aeolian islands, Italy): Multivariate analysis of petrographic and radiometric data
- Autori: Lanzo, G; Basile, S; Brai, M; Rizzo, S
- Anno di pubblicazione: 2010
- Tipologia: Articolo in rivista (Articolo in rivista)
- Parole Chiave: Lipari volcanic products, XRF, Gamma-ray spectrometry, environmental radioactivity, multivariate analysis
- OA Link: http://hdl.handle.net/10447/50464
Abstract
A petrographicandradiometricstudy,alongwithstatisticalmultivariateanalysisofvolcanicproductsof the islandofLipari(Aeolianislands,Italy)wascarriedout.ThevolcanologicalhistoryofLipariwas reconstructed defining twostages(pre-andpost-erosivestages)furtheronsubdividedinfourvolcanic phases,eachofwhichcharacterizedbyproductswithaparticularchemicalcompositionandseparated by stratigraphicunconformities.Thecorrelationsbetweenpetrographicfeatures,determinedbyX-ray fluorescence, andvolcanologicalhistoryoftheislandhighlightagradualdifferentiationwithyounger rocksshowingamoreacidchemicalcompositionthantheolderones.Radiometricfeatures,andin particularthecontentofprimordialradionuclides 238U, 232Th and 40K,havebeenmeasuredthrough gamma-rayspectrometrywithhyper-puregermaniumdetector. Thedifferentvolcaniclithologies,suchasbasalts,andesitesandrhyolites,havebeencharacterizedby petrographicdiagrams.Thecalculateddoseratehasalsobeenusedasanadditionalclassificationparameter. Olderproductsshowlowalkalicontentthantheyoungerones.Thisisrelatedwiththeincreasingof incompatibleelements,suchasuraniumandthorium,intheyoungerproducts. Principalcomponentsandhierarchicalclusteringstatisticalanalyseshaveprovidedadditionalinfor- mation onsampledifferentiationandsimilarities.