Z. dt. Geol. Ges.147/1S. 101-123, 9 Abb., 3 Tab.de.Txt.Stuttgart, März 1996

Die Vulkanite der Tyros-Schichten Kretas und des Peloponnes
- orogene Andesite oder anorogene Trapp-Basalte?

[The volcanic rocks of the Tyros beds from Crete and Peloponnesus
orogenic andesites or onorogenic trap-basalts?]


Authoren : Ulrich Friedrich Dornsiepen & Emmanuil Manutsoglu

Abstract :

Triassic volcanic rocks are an essential rock type of the Tyros beds of Crete and the Peloponnesus. Previous investigations interpreted them as rocks of a calcalkaline character, typical for active continental margin settings. Processes of subduction in the External Hellenides during the Triassic are however not consistent with geological observations. Studies concerning Mesozoic trap­basalts of Gondwana and Siberia revealed the occurrence of Low­Ti­Trap­Basalts, resembling rocks of calcalkaline character. A new evaluation of so far unpublished geochemical data concerning volcanic rocks of the Tyros beds of the Peloponnesus shows a comparable low­Ti signature, but they do not all represent calcalkaline rocks. The Sr/Nb­relation is significantly different regarding both rock types. It is above 100 in calcalkaline rocks and only less than 50 in Low­Ti­Trap­Basalts. These results do not favour the possibility of subduction processes in the External Hellenides during the Triassic.

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