<abstract xml:lang="en" xmlns="http://www.w3.org/1999/xhtml"><p>K-Ar determinations have been conducted on the background of the earlier radiometric data in the eastern part of the northern Karkonosze-Izera envelope of the granite massif, composed of different varieties of granites, gneisses and mica schists. The values of the K-Ar age for minerals and rocks from the Karkonosze-Izera block lie in the wide interval ranging from 226.0±6.7 Ma to 386.1±3.0 Ma. The K-Ar age data obtained by volumetric method oscillate between 308±21 and 372±26 Ma. Most biotite K-Ar age values of the Izera granite-gneisses complex give an average age of 316.1±3.3 Ma. They correspond to the cooling age of the Karkonosze pluton while the data below 300 Ma are minimum age values that postdate the last granite intrusion of the Krkonoše-Jizera pluton. The obtained results over 300 Ma are mixed apparent ages between the age of the Karkonosze and the Izera granite ages. The K-Ar dates in the studied region have been compared with fission-track (FT) ages of zircon and titanite in the same area which display another distribution pattern.</p></abstract>

K-Ar determinations have been conducted on the background of the earlier radiometric data in the eastern part of the northern Karkonosze-Izera envelope of the granite massif, composed of different varieties of granites, gneisses and mica schists. The values of the K-Ar age for minerals and rocks from the Karkonosze-Izera block lie in the wide interval ranging from 226.0±6.7 Ma to 386.1±3.0 Ma. The K-Ar age data obtained by volumetric method oscillate between 308±21 and 372±26 Ma. Most biotite K-Ar age values of the Izera granite-gneisses complex give an average age of 316.1±3.3 Ma. They correspond to the cooling age of the Karkonosze pluton while the data below 300 Ma are minimum age values that postdate the last granite intrusion of the Krkonoše-Jizera pluton. The obtained results over 300 Ma are mixed apparent ages between the age of the Karkonosze and the Izera granite ages. The K-Ar dates in the studied region have been compared with fission-track (FT) ages of zircon and titanite in the same area which display another distribution pattern.

Radiometric Age Analyses of Rocks from the Northern Envelope of the Karkonosze Massif, the Sudetes, Poland: A Comparative Geochronological Study

Polish Geological Institute - National Research Institute, ul. Rakowiecka 4, 00-975 Warszawa, Poland

Institute of Physics, Marie Curie-Sklodowska University, pl. Marii Curie-Skłodowskiej 1, 20-031 Lublin, Poland

Geochronometria

K-Ar determinations have been conducted on the background of the earlier radiometric data in the eastern part of the northern Karkonosze-Izera envelope of the...

Radiometric Age Analyses of Rocks from the Northern Envelope of the Karkonosze Massif, the Sudetes, Poland: A Comparative Geochronological Study

Published Online: Dec 22, 2009

Page range: 33 - 39

DOI: https://doi.org/10.2478/v10003-009-0016-2

Keywords
K-Ar, radiometric age, geochronology, the Karkonosze-Izera Block

This content is open access.

Radiometric Age Analyses of Rocks from the Northern Envelope of the Karkonosze Massif, the Sudetes, Poland: A Comparative Geochronological Study

Published Online: Dec 22, 2009

Page range: 33 - 39

DOI: https://doi.org/10.2478/v10003-009-0016-2

KeywordsK-Ar, radiometric age, geochronology, the Karkonosze-Izera Block

This content is open access.

Keywords
K-Ar, radiometric age, geochronology, the Karkonosze-Izera Block