Lithofacies characteristics of the Smrekovec volcaniclastics, northern Slovenia


  • Polona Kralj



The Smrekovec mountains are characterised by a widespread occurrence of volcanic rocks of the Upper Oligocene age. Their development is closely related to volcanic activity which resulted in the formation of a submarine stratovolcano complex, emplaced onto pre-Tertiary carbonate basement and locally, on Upper Oligocene marine marls and silts. Magma composition varied with time during volcanic activity. The original tholeiitic magmas very likely underwent a differentiation due to low pressure crystal fractionation, resulting in the development of andesitic and finally rhyodacitic magmas. The early stage of volcanic activity was dominantly non-explosive; the main style of fragmentation was autoclastic, related to chill and quench processes that affected lavas and high-level intrusive bodies. During the late-stage of volcanic activity, explosive volcanism was also present, being most probably related to magmatic and combined magmatic-hydrovolcanic activity. Explosions also seem to have generated or triggered volcaniclastic debris flows and turbidity ash flows. Shallow intrusive bodies (syn-volcanic sills and feeder dykes) were a local source of heat that generated hydrothermal/geothermal conditions in the enclosing, water-saturated volcaniclastic sediments. Consequently laumontite, analcime, clinoptilolite, heulandite, thomsonite, yugawaralite, prehnite, pumpellyite, albite, apophyllite, epidote, sphene, chlorite and mixed-layered clay minerals developed as replacements of the primary constituents, interstitial fillings and vein minerals. 


How to Cite

Kralj, P. (1996). Lithofacies characteristics of the Smrekovec volcaniclastics, northern Slovenia. Geologija, 39(1), 159–191.




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