Nowe dane o budowie geologicznej Góry Św. Anny (Śląsk Opolski)

Abstract

A kaldera from the Góra Św. Anny. Upper Silesia: New data on the geologic structure Primary tectonic and stratigraphic positions of the Triassic and Upper Cretaceous sedimentary rocks, occuring as xenoliths in the Góra Św. Anny nephelinite have been established. They formed a sedimentary cover prior to the eruption. Thermic and hydrothermal influence of the intrusion led to the formation of jaspers. Taking isotopic and palaeomagnetic data into account, the Góra Św. Anny is interpreted as relic of a deeply eroded caldera. A new, five-stage model of the development of this caldera is proposed.