Use of Be-10 exposure ages and Schmidt hammer data for correlation of moraines in the Krkonose Mountains, Poland/Czech Republic

摘要

Exposure ages and relative-age data are presented from eight sites in the Lomnica and Lomniczka valleys to provide essential information for reconstructing local glaciation chronology. A combination of Be-10 exposure ages and Schmidt hammer data obtained for moraines indicate relatively short period of glacier accumulation lasting from 17.0 +/- 0.4 ka to 13.6 +/- 0.9 ka. Exposure age of 8.4 +/- 0.3 ka measured on the lowermost section of the Lomnica cirque headwall further confirms the view of glacier preservation in favourable sites until the beginning of the Holocene. A comparison of the obtained chronological data with timing of mountain glaciation in the nearby Upa Valley is used to propose the first correlative model of Late Quaternary glaciation in the eastern part of the Krkonose Mountains. The correlation implies that the lowermost preserved moraines originated during the local maximum of the last glaciation whereas recessional moraines were deposited until the Lateglacial period. A subsequent melting of glaciers terminated at the beginning of the Holocene. The implications of the model are discussed and further investigations are suggested to extend its validity to the whole mountain area.