Radiometric dating of the Tertiary volcanics in Lower Silesia, Poland.II. K-Ar and palaeomagnetic data from Neogene basanites near Lądek Zdrój, Sudetes Mts

Abstract

Datowanie radiometryczne trzeciorzędowych wulkanitów Dolnego Śląska. II. Daty K-Ari wyniki badań paleomagnetycznych neogeńskich bazanitów okolic Lądka Zdroju w Sudetach K-Ar dating of Cenozoic basaltic rocks (one plug and two lava flows) in the Lądek Zdrój area, Sudetes Mts, Poland (50.5°N, 17°E), has established their Neogene (Messinian-Zanclean) ages: from 5.46 to 3.83 Ma. They are the youngest manifestations o f the Cenozoic vulcanicity in the Polish part o f the Bohemo-Silesian Belt. According to new petrological and geochemical data, the studied rocks belong to basanites which display slightly differentiated mineral and chemical composition between the exposures. The basanites were magnetized most probably in one or more than one normal subchrons during middle part o f the reversed Gilbert chron (between 4.18 and 5.23 Ma).