engleski

Zeolite deposits in Croatia

In spite of the fact that zeolites have been found at several locations in Croatia, so far only two regions with economically interesting concentrations are known, both situated in northern part of the country. The first one is located in the Macelj area in north-western part of Hrvatsko zagorje (NW Croatia) in which Lower Miocene (Egerian-Ottnangian) volcaniclastic rocks crop out on several localities. They have variable primary composition, and contain various alteration products of volcanic glass. The alteration products comprise zeolites (clinoptilolite as the most abundant zeolite, analcime and mordenite), clay minerals (smectite, authigenic mica), SiO2 phases and authigenic feldspars. Performed investigations indicate that alteration products are the result of burial diagenesis. In the other deposit, located in the vicinity of village Poljanska in Požega Valley, on the southern slopes of Mt. Papuk (Slavonian Mountains, N Croatia) analcime-bearing rocks can be found. Analcime was formed within closed hydrological system i.e. shallow saline alkaline lake which existed during early Miocene (Ottnangian) time.

analcime; clinoptilolite; Croatia; mordenite; zeolite

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