@prefix prodottidellaricerca: . @prefix istituto: . @prefix prodotto: . istituto:CDS043 prodottidellaricerca:prodotto prodotto:ID187714 . @prefix pubblicazioni: . @prefix unitaDiPersonaleInterno: . unitaDiPersonaleInterno:MATRICOLA15051 pubblicazioni:autoreCNRDi prodotto:ID187714 . @prefix modulo: . modulo:ID8075 prodottidellaricerca:prodotto prodotto:ID187714 . @prefix rdf: . @prefix retescientifica: . prodotto:ID187714 rdf:type retescientifica:ProdottoDellaRicerca , prodotto:TIPO1101 . @prefix rdfs: . prodotto:ID187714 rdfs:label "OPHIOLITIC MAGMATISM IN THE LIGURIAN TETHYS - AN ION MICROPROBE STUDY OF BASALTIC CLINOPYROXENES (Articolo in rivista)"@en . @prefix xsd: . prodotto:ID187714 pubblicazioni:anno "1993-01-01T00:00:00+01:00"^^xsd:gYear ; pubblicazioni:doi "10.1007/BF00321215"^^xsd:string . @prefix skos: . prodotto:ID187714 skos:altLabel "
VANNUCCI R. 1,2; RAMPONE E. 3; PICCARDO G.B. 3; OTTOLINI L. 2; BOTTAZZI P. 2 (1993)
OPHIOLITIC MAGMATISM IN THE LIGURIAN TETHYS - AN ION MICROPROBE STUDY OF BASALTIC CLINOPYROXENES
in Contributions to mineralogy and petrology
"^^rdf:HTML ; pubblicazioni:autori "VANNUCCI R. 1,2; RAMPONE E. 3; PICCARDO G.B. 3; OTTOLINI L. 2; BOTTAZZI P. 2"^^xsd:string ; pubblicazioni:paginaInizio "123"^^xsd:string ; pubblicazioni:paginaFine "137"^^xsd:string ; pubblicazioni:numeroVolume "115"^^xsd:string . @prefix ns11: . prodotto:ID187714 pubblicazioni:rivista ns11:ID598554 ; pubblicazioni:numeroFascicolo "2"^^xsd:string ; skos:note "ISI Web of Science (WOS)"^^xsd:string ; pubblicazioni:affiliazioni "1. UNIV PAVIA,DIPARTIMENTO SCI TERRE,VIA BASSI 4,I-27100 PAVIA,ITALY; \n2. CNR,CNR,CTR STUDIO CRISTALLOCHIM & CRISTALLOG,I-27100 PAVIA,ITALY; \n3. UNIV GENOA,DIPARTIMENTO SCI TERRE,I-16132 GENOA,ITALY"^^xsd:string ; pubblicazioni:titolo "OPHIOLITIC MAGMATISM IN THE LIGURIAN TETHYS - AN ION MICROPROBE STUDY OF BASALTIC CLINOPYROXENES"^^xsd:string ; prodottidellaricerca:abstract "Ion microprobe data (REE, Na, Sc, Ti, V, Cr, Sr, Zr) of unaltered clinopyroxenes in the ophiolitic basalts from the Northern Apennines have been used in a cpx-based geochemical modelling of MORB magmatism from both External (EL) and Internal (IL) sectors of the Ligurian Tethys (i.e. Jurassic Ligure-Piemontese basin), alternative to the more common whole-rock approach. Clinopyroxenes from EL basalts display slightly fractionated LREE (Ce(N)/Sm(N) approximately 0.5) and HREE (Gd(N)/Yb(N) approximately 1.5) patterns and large variations in the REE composition (up to 6 times from microphenocryst cores to interstitial clinopyroxenes). Interstitial clinopyroxenes in IL basalts are similar to the microphenocrysts from the most primitive EL basalts. By contrast, IL microphenocrysts are characterized by greater LREE (Ce(N)/Sm(N) approximately 0.3) and lesser HREE (Gd(N)/Yb(N) < 1.2) fractionation. The comparison of trace element variations in whole-rocks and clinopyroxenes clearly shows that the olivine and plagioclase portion of the fractionation sequence is poorly represented by the EL and IL basalts. In fact, ophiolitic basalts mainly consist of a minor interstitial glass (now deeply altered) associated with a prevailing plagioclase-clinopyroxene assemblage crystallized from liquids significantly evolved along the olivine-plagioclase-clinopyroxene saturation boundary. Thus, bulk rock chemistry is largely governed by clinopyroxene composition. This, in addition to alteration, indicates that the bulk rock chemistry does not provide reliable chemical information to constrain the composition and the generation of the parental magmas. Unfortunately, most clinopyroxenes are characterized by complex zoning, probably caused by disequilibrium partitioning during crystal growth as a result of kinetic factors. On this ground, estimation of melt chemistry and inferences about the origins of these basalts are only allowed by the core compositions of microphenocrystic clinopyroxenes. Modelling. of (Nd/Yb)N and Ti/Zr in the parental magmas, as deduced from the clinopyroxene compositions, indicates thata EL and IL basalts do not represent products of different mantle source compositions. Rather, they were generated by varying degrees of fractional melting in the spinel stability field, lower for the EL (a few percent) relative to IL, totalling no more than 10% of an asthenospheric MORB source, and leaving in the residua clinopyroxene with REE patterns similar to those shown by IL suboceanic type peridotites. Accordingly, these latter are interpreted as refractory residua after MORB-generating fractional melting occurred during rifting and opening of the Ligure-Piemontese basin. By contrast, residual clinopyroxenes from the EL subcontinental type peridotites are not consistent with low degrees of fractional melting, in agreement with the current interpretation that EL peridotites are unrelated to the MORB magmatism in the Ligure-Piemontese basin and represent lithospheric mantle material already emplaced towards the surface by a tectonic denudation mechanism during the early stages of oceanic rifting."@en ; prodottidellaricerca:prodottoDi modulo:ID8075 , istituto:CDS043 ; pubblicazioni:autoreCNR unitaDiPersonaleInterno:MATRICOLA15051 . @prefix parolechiave: . prodotto:ID187714 parolechiave:insiemeDiParoleChiave . ns11:ID598554 pubblicazioni:rivistaDi prodotto:ID187714 . parolechiave:insiemeDiParoleChiaveDi prodotto:ID187714 .