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Krytyczne uwagi na temat rekonstrukcji geometrii powierzchni lodowców w polskich Tatrach Wysokich

100%

Zasadni J.

tom Vol. 57, nr 7

607-613

The paper presents critical remarks on reconstruction by Makos and Nowacki (2009). The authors worked out a model of ice-surface geometry and equilibrium line altitude (ELA) of glacier which existed in the Białka Valley system (High Tatra Mts.) during the Last Glacial Maximum (LGM), utilizing mapped trimlines in accumulation areas and literature data about glacier extent in ablation areas. Some palaeoclimate implications from this study indicate LGM-modern temperature amplitude ca 5.5grade C from ELA depression and prevailing southern atmospheric circulation pattern during the LGM in the Tatra Mts. The reconstruction does not comprise the whole former glacier system of the valley and therefore the use of arbitrary assumed accumulation area ratio (AAR) resulted in considerable error in determinations of ELA. It is concluded that ELA calculated for 1400 m a.s.l. was obtained with AAR 0.77 value instead of intended 0.65–0.67. Critical remarks also concern ice-surface geometry which is in some places inconsistent with glaciological conformities. The LGM modern temperature amplitude was calculated without considering precipitation changes between LGM and modern time and on the basis of questionable position of modern ELA position, therefore it can not be treated as a valuable one. Similarly, the thesis about southern atmospheric circulation is here discussed in detail. It is concluded that the evidences presented by Makos and Nowacki (2009) can not support nor contradict this thesis. It should be treaded as a speculation made under the influence of Alpine results.

Metody rekonstrukcji wysokości linii równowagi lodowców

100%

Zasadni J.

tom 81

nr 1-2

Osady późnego glacjału i holocenu w dolinie Tuxer (Alpy Zillertalskie, Austria)

100%

Zasadni J.

2007

nr 04

Research history on the Tatra Mountains glaciations

63%

Kłapeta P. , Zasadni J.

tom Vol. 51/52

43--85

In this paper, we provide a brief history of glacial geomorphologic research in the Tatra Mountains with a special focus on glacial chronologies. We provide critical comments on previously published glacial chronologies and identify relevant gaps in knowledge on Tatra mountain glaciations suggesting future challenges and the focus of scientific research. Distinct differences in applied methodologies, presented conceptions, and research paradigms over 160 years of research enable us to distinguish four phases of scientific research on Tatra mountain glaciation (pioneer phase, mapping phase, geochronological phase and meta-analysis phase). These four phases follow the universal sequence of glacial geomorphologic research history defined by P.D. Hughes et al. (2006) and P.D. Hughes and J.C. Woodward (2016) for Mediterranean mountain areas. In the last two phases, the glacial chronology was substantially supported with radiometric dating of landforms and sediments as well as paleobotanical data obtained from intra-moraine sites. The current meta-analysis phase of research provides dating techniques using terrestrial cosmogenic nuclide (TCN) exposure ages and glacier-climate modeling. The present-day TCN dataset for the Tatra Mountains includes 300 individual ages (10Be and 36Cl together). We underscore the fact that this dataset has substantially verified many key issues in the glacier geochronology of the Tatra Mountains. This is particularly true of the Last Glacial Maximum (LGM) – the Lateglacial chronology for which abundant datings are currently available and their number is still increasing. However, it is challenging to evidence the chronology and extent of the most extensive glaciation(s) (MEG).