O charakterze petrograficznym otoczaków skał wulkanicznych w utworach dolnego karbonu okolic Zalasu

Abstract

ON THE PETROGRAPHIC CHARACTER OF PEBBLES FROM VOLCANIC ROCKS IN LOWER CARBONIFEROUS DEPOSITS NEAR ZALASIn further pursuing their previous argumentation (1958) with T. Piłatowa (1957, 1960) the authors mention evidence supporting their assignment of pebbles from Lower Carboniferous volcanic rocks in the vicinity of Zalas (the Cracow Region) to the group of acidic rocks (rhyolite-granite) and not to the group of diorites or syenites. The author's assertment is based on the mineral composition of these rocks which contains ca. 23 weight per cent of quartz, also on a comparison of Niggli's parametres computed from the chemical analysis of one of the pebbles (fig. 1) with Niggli's patametres of various magmas (1923).