Summary
On the basis of whole-rock and mineral chemistry two main magmatic groups can be established for the Paleozoic Volcanism of the Carnian Alps. High-Ti Volcanics (HTV) and Low-Ti Volcanics (LTV). Spilitization processes have not masked the primary magmatic character. The two groups are characterized by very different trace element patterns and cannot be correlated by a fractionation process. The HTV require an enriched mantle source whereas the geochemistry of the LTV indicates strong crustal contamination. Both magmatic groups are consistent with a major rifting episode. The contamination via assimilation of crustal rocks of the LTV group implies that rifting developed in a continental area.
Zusammenfassung
Auf der Grundlage von Gesteins- und Mineralchemie der paläozoischen Vulkanite der Karnischen Alpen können zwei magmatische Hauptgruppen unterschieden werden: die Hoch-Ti Vulkanite (HTV) und die Nieder-Ti Vulkanite (LTV). Der Prozess der Spilitisation vermochte die ursprünglichen magmatischen Charakteristika nicht zu überdecken. Die zwei Gruppen sind durch sehr verschiedene Spurenelementgehalte charakterisiert und können nicht durch einen Differentiationsprozeß verknüpft werden. Die HTV erfordern eine angereicherte „mantle source”, während die Geochemie der LTV deutlich auf Kontamination hinweist. Beide magmatische Gruppen sind aus einer „rifting” Episode hervorgegangen. Die Kontamination der LTV-Gruppe durch Assimilation von Krustengesteinen zeigt, daß das „rifting” sich in einer kontinentalen Umgebung entwickelte.
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Sinigoi, S., Beltrame, C., Coltorti, M. et al. Petrogenesis of the paleozoic magmatic rocks of the Carnian Alps. Mineralogy and Petrology 38, 263–276 (1988). https://doi.org/10.1007/BF01167092
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DOI: https://doi.org/10.1007/BF01167092