caa a22 4500 467890218 CHVBK 20180406152746.0 cr unu---uuuuu 170328e20060101xx s 000 0 eng 10.1007/s00710-005-0092-6 doi (NATIONALLICENCE)springer-10.1007/s00710-005-0092-6 Gabbroic xenoliths in tuff-breccia pipes from the Hyblean Plateau: insights into the nature and composition of the lower crust underneath South-eastern Sicily, Italy [Elektronische Daten] [V. Scribano, G. Sapienza, R. Braga, L. Morten] Summary: Crust-derived xenoliths hosted by Miocene basaltic diatremes in the Hyblean Plateau (south-eastern Sicily, Italy) provide new information regarding the nature of a portion of the central Mediterranean lower crust. These xenoliths can be divided into three groups: gabbros (plagioclase + clinopyroxene + Fe-Ti oxides ± apatite ± amphibole ± Fe-rich green spinel), diorites (An-poor plagioclase, clinopyroxene ± Fe-Ti oxides ± orthopyroxene) and mafic granulites (plagioclase + clinopyroxene + green spinel ± orthopyroxene ± Fe-Ti oxides). Gabbros form the main subject of this paper. They represent cumulates whose igneous texture has been locally obliterated by metamorphic recrystallization and shearing. They were permeated by Fe-Ti-rich melts related to tholeiitic-type fractional crystallisation. Incompatible element ratios (Zr/Nb = 5-26; Y/Nb = 1.4-11) indicate that these cumulate gabbros derived from MORB liquids. Late-stage and hydrothermal fluids caused diverse, sometimes important, metasomatic trasformations. Petrographic and geochemical comparison with gabbroids from well-known geodynamic settings show that the Hyblean lower crustal xenoliths were probably formed in an oceanic or oceanic-continent transition environment. Springer-Verlag/Wien, 2005 Scribano V. Dipartimento di Scienze Geologiche, Università di Catania, Catania, Italy aut Sapienza G. Dipartimento di Scienze della Terra e Geologico-Ambientali, Università di Bologna, Bologna, Italy aut Braga R. Dipartimento di Scienze della Terra e Geologico-Ambientali, Università di Bologna, Bologna, Italy aut Morten L. Dipartimento di Scienze della Terra e Geologico-Ambientali, Università di Bologna, Bologna, Italy aut Mineralogy and Petrology Springer-Verlag 86/1-2(2006-01-01), 63-88 0930-0708 86:1-2<63 2006 86 710 https://doi.org/10.1007/s00710-005-0092-6 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00710-005-0092-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Scribano V. Dipartimento di Scienze Geologiche, Università di Catania, Catania, Italy aut NATIONALLICENCE 700 1- Sapienza G. Dipartimento di Scienze della Terra e Geologico-Ambientali, Università di Bologna, Bologna, Italy aut NATIONALLICENCE 700 1- Braga R. Dipartimento di Scienze della Terra e Geologico-Ambientali, Università di Bologna, Bologna, Italy aut NATIONALLICENCE 700 1- Morten L. Dipartimento di Scienze della Terra e Geologico-Ambientali, Università di Bologna, Bologna, Italy aut NATIONALLICENCE 773 0- Mineralogy and Petrology Springer-Verlag 86/1-2(2006-01-01), 63-88 0930-0708 86:1-2<63 2006 86 710 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer