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6902199 
Journal Article 
Phase equilibrium modelling of the amphibolite to granulite facies transition in metabasic rocks (Ivrea Zone, NW Italy) 
Kunz, BE; White, RW; , 
2019 
Yes 
Journal of Metamorphic Geology
ISSN: 0263-4929
EISSN: 1525-1314 
WILEY 
HOBOKEN 
37 
7 
935-950 
English 
WOS:000479310300004 
The development of thermodynamic models for tonalitic melt and the updated clinopyroxene and amphibole models now allow the use of phase equilibrium modelling to estimate P-T conditions and melt production for anatectic mafic and intermediate rock types at high-T conditions. The Permian mid-lower crustal section of the Ivrea Zone preserves a metamorphic field gradient from mid amphibolite facies to granulite facies, and thus records the onset of partial melting in metabasic rocks. Interlayered metabasic and metapelitic rocks allows the direct comparison of P-T estimates and partial melting between both rock types with the same metamorphic evolution. Pseudosections for metabasic compositions calculated in the Na2O-CaO-K2O-FeO-MgO-Al2O3-SiO2-H2O-TiO2-O (NCKFMASHTO) system are presented and compared with those of metapelitic rocks calculated with consistent end-member data and a-x models. The results presented in this study show that P-T conditions obtained by phase equilibria modelling of both metabasic and metapelitic rocks give consistent results within uncertainties, allowing integration of results obtained for both rock types. In combination, the calculations for both metabasic and metapelitic rocks allows an updated and more precisely constrained metamorphic field gradient for Val Strona di Omegna to be defined. The new field gradient has a slightly lower dP/dT which is in better agreement with the onset of crustal thinning of the Adriatic margin during the Permian inferred in recent studies. 
Ivrea Zone; metabasic rocks; mineral equilibria modelling; partial melting; thermocalc 
5th Granulites and Granulites Meeting 
Ullapool, SCOTLAND