TY - JOUR
TI - Carbonatitic dykes during Pangaea transtension (Pelagonian Zone, Greece)
AU - Schenker, F.L.
AU - Burg, J.-P.
AU - Kostopoulos, D.
AU - Baumgartner, L.P.
AU - Bouvier, A.-S.
JO - LITHOS - AMSTERDAM
PY - 2018
VL - 302-303
TODO - null
SP - 329-340
PB - Elsevier B.V.
SN - 0024-4937
TODO - 10.1016/j.lithos.2018.01.011
TODO - carbonatite;  dike;  fenite;  Hercynian orogeny;  magmatism;  Pangaea;  Permian;  rare earth element;  Tethys, Greece;  Pelagonia
TODO - Carbonatitic dykes surrounded by K-Na-fenites were discovered in the Pelagonian Zone in Greece. Their carbonate portions have an isotopic mantle signature of δ13C and δ18O ranging from −5.18 to −5.56 (‰ vs. VPDB) and from 10.68 to 11.59 (‰ vs. VSMOW) respectively, whereas their mafic silicate portions have high Nb, Ta and ɛNd values, typical of alkaline basalts. Textural relationships hint at a cogenetic intrusion of silicate and carbonate liquids that according to antithetic REE profiles segregated at shallow depths (<0.6 GPa) from a parental melt sourced deeper in the mantle. Fenites bear similar REE abundances to mafic rocks but with high Rb-Ba and low Nb-Ta values. SHRIMP II U-Pb analyses of magmatic zircon cores (δ18O = 7.21–7.51) from a carbonate-bearing syenitic amphibolite yielded a Permian intrusion age at 278 ± 2 Ma, considerably older than a Cretaceous (118 ± 4 Ma) greenschist overprint obtained from metamorphic zircon rims (δ18O = 6.78–7.02). From 300 to 175 Ma the ɛNd of the Pelagonian magmatism rose irregularly to more primitive values attesting to a higher increment of asthenosphere-derived melts. In this context, the carbonatite formed within a transtensional regime of an intra-Pangaea dextral transform fault that signalled the forthcoming penetrating breakoff of the supercontinent, manifested in the Permo-Triassic. © 2018 The Authors
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