caa a22 4500 477064566 CHVBK 20180405111409.0 cr unu---uuuuu 170330e19960601xx s 000 0 eng 10.1007/BF02422231 doi (NATIONALLICENCE)springer-10.1007/BF02422231 Gabbro-derived granulites from External liguride units (northern Apennine, Italy): implications for the rifting processes in the western Tethys [Elektronische Daten] [M. Marroni, R. Tribuzio] In Santonian-Early Campanian sedimentary melanges of the External Liguride units (northern Apennine), slide blocks of subcontinental mantle and MOR basalts are associated with lithologies derived from the continental crust. One of these sedimentary melanges, the Mt. Ragola complex, is characterized by the close association of mantle ultramafic, mafic and quartzo-feldspathic granulites. Mafic granulites show a wide compositional range. They generally display a marked metamorphic layering, but undeformed rocks which preserve a gabbroic fabric are found locally. The most frequent lithologies are Al-spinel gabbronorites, generally containing minor olivine, and Fe-Ti oxidebearing gabbronorites. Troctolites, olivine gabbronorites and anorthosites were also recovered. Relics of primary textures as well as mineral and bulk-rock compositional variations indicate a comagmatic intrusive origin for the protoliths of the mafic granulites. This intrusive mafic complex underwent a subsolidus reequilibration under granulite facies conditions, at 0.6-0.9 GPa and 810-920°C, and was derived from crystallization at intermediate levels of tholeiite-derived liquids, possibly affected by crustal contamination. Its primary features are similar to those of the upper zone of the Ivrea layered complex. The gabbroic protolith for the granulites of External Liguride units were probably crystallized into the extending Adria lithosphere in relation to the initial stages of the opening of the western Tethys. Springer-Verlag GmbH & Co KG, 1996 Gabbro nationallicence Granulite nationallicence External Liguride units nationallicence Northern Apennine nationallicence Western Tethys nationallicence Adria continental margin nationallicence Marroni M. Dipartimento di Scienze della Terra, Università di Pisa, via S. Maria 53, I-56100, Pisa, Italy aut Tribuzio R. Dipartimento di Scienze della Terra, Università di Pavia, via Ferrata 1, I-27100, Pavia, Italy aut Geologische Rundschau Springer-Verlag 85/2(1996-06-01), 239-249 0016-7835 85:2<239 1996 85 531 https://doi.org/10.1007/BF02422231 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02422231 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Marroni M. Dipartimento di Scienze della Terra, Università di Pisa, via S. Maria 53, I-56100, Pisa, Italy aut NATIONALLICENCE 700 1- Tribuzio R. Dipartimento di Scienze della Terra, Università di Pavia, via Ferrata 1, I-27100, Pavia, Italy aut NATIONALLICENCE 773 0- Geologische Rundschau Springer-Verlag 85/2(1996-06-01), 239-249 0016-7835 85:2<239 1996 85 531 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer