Abstract
Petrography, mineral chemistry, metamorphic evolution and geothermo-barometric estimations concerning the Pohorje metabasites and metaultrabasites are presented and discussed. Consistently with the evolution detected in the associated eclogites, and disregarding serpentinization, these rocks record a three-stage metamorphic evolution: (i) an older, dry, high-pressure/high-temperature recrystallization;(it) a later, lower-pressure/lower temperature granulitic stage;(iii) a younger, epidote-amphibolite overprint. The latter water-controlled recrystallization is believed to be Alpine, while the main part of the metamorphic history is to be considered pre-Alpine. Such chronological classification is consistent with the prevailing interpretation concerning similar rocks in the Eastern Alps, and is supported by the occurrence of foliated leucocratic veins which crosscut the metaultrabasites and the eclogites.
Riassunto
Le metabasiti e le metaultrabasiti affioranti nell’area di Pohorje vengono studiate dai punti di vista petrografico, petrologico, del chimismo delle fasi mineralogiche e dell’evoluzione metamorfica. Prescindendo dalla serpentinizzazione. talc evoluzione risulta congruente con quella nconosciuta nelle eclogiti associate e precisamente articolata in tre stadi: i) una antica ricristallizzazione sotto alti valon di T e P in condizioni anidre;ii) un successivo stadio granulitico svoltosi sotto valori di TeP piu bassi; iii@#@) una più recente rielaborazione in facies delle antiboliti ad epidoto, in presenza di H2O. Quest’ultimo stadio viene considerato di età Alpina. Invecc, sulla base di considerazioni geologiche, i precedenti stadi sono ritenuti pre-Alpini, congruentemente con le opinioni prevalenti nella letteratura regionale su analoghe rocce austroalpine. Tale interpretazione e awalorata dalla presenza di vene leucocratiche foliate che attraversano le metabasiti e le eclogiti studiate.
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Nella seduta del 15 dicembre 1990.
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Hinterlechner-Ravnik, A., Sassi, F.P. & Visonà, D. The Austridic eclogites, metabasites and metaultrabasites from the Pohorje area (Eastern Alps, Yugoslavia): 2. The metabasites and metaultrabasites, and concluding considerations. Rend. Fis. Acc. Lincei 2, 175–190 (1991). https://doi.org/10.1007/BF03001420
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DOI: https://doi.org/10.1007/BF03001420