Publisher © Czech Geological Survey, ISSN: 2336-5757 (online), 0514-8057 (print)
Intrusive rocks in the Barrandian Proterozoic of the Plasy area
Abstract
The Neoproterozoic volcanosedimentary sequences were intruded by a variety of dyke rocks and minor stocks. A reconnaissance survey in the Plasy area focused on sixty six intrusive occurrences that include dykes of diabases, spessartites, quartz diorites and microdiorites, subvolcanic trachytes and dacites, several types of granite porphyries as well as six mafic stocks (gabbros, diorites, spessartites). Trachytes, dacites and microdiorites appear to be restricted to this area whereas granite porphyries bear similarities with the Kožlany intrusive zone, and granodiorite porphyries, spessartites and diabases each belong to regionally extensive dyke swarms. Field measurements of the whole-rock magnetic susceptibility indicate a broad range of values between 2 . 10-5 and 4 . 10-1 [SI]. Individual data correlate with the abundance of mafic minerals and the modal proportion of magnetite.
