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Aktywność neotektoniczna Pasma Lubania (Gorce) na podstawie analizy parametrów morfometrycznych

Buczek Krzysztof, Górnik Marek

Przegląd Geologiczny

2019

Vol. 67, nr 4

270--278

The aim of this paper is to use a relative tectonic index (Iat) in order to evaluate tectonic activity in the intermediate mountain area of the Lubań Range. To estimate the tectonic activity in the study area, we analyzed 6 DEM derived geomorphic indices for 66 basins: the stream-gradient index (SL), asymmetry factor (Af), basin shape ratio (Bs), hypsometric integral (Hi), valley floor width-valley height ratio (Vf) and mountain-front sinuosity (Smf). These parameters were combined to obtain the relative tectonic activity index (Iat). According to Iat values, ca. 25% of the Lubań Range was classified as areas of relatively high tectonic activity and ca. 72% as moderately tectonically active. The Iat values suggest a higher relative tectonic activity in the western part of the range, since some morphometric indices, like HI and SL, indicate a higher rate of tectonic uplift along the Dunajec Fault and normalfaults on the northern slopes of the Lubań Range. The rate of the tectonic uplift obtained from the Iat values is similar to that derivedfrom river incision. Morphometric analysis as well as field evidence of active tectonics, such as triangularfacets, suggest a high rate of tectonic uplift along the northern margins of the range and probably along the eastern slopes of the Lubań Range. The high relative tectonic activity on the southern slopes in the western part of the Lubań Range is probably related to active subsidence of the Nowy Targ Basin

Dated landslides in the Gorce Mts. (Polish Outer Carpathians) : preliminary results

Buczek Krzysztof

Geological Quarterly

2019

Vol. 63, No. 4

849--860

Preliminary results of dating landslides in the Gorce Mts. (Polish Outer Carpathians) are given, where ages of landslide activity have been poorly constrained. Four landslide zones with minerogenic mires (fens) were selected in order to determine the age of landslide movements, with depositional sequences of six fens being investigated by boreholes. Conventional radiocarbon dating of wood samples from mineral sediments sealing the landslide depressions was carried out to establish the age of landslide formation or rejuvenation. Loss on ignition analyses were obtained at 2.5 cm intervals along the cores to indicate possible delivery of allochthonous material into the peat bogs. Landslide formation in the Gorce Mts. corresponds to phases of mass movement hitherto identified in the Polish Outer Carpathians. Increased mass movements activity in the Gorce Mts. relate to cold and humid periods of the Holocene which occurred: ~11.1 ka cal BP, 8.6-8.0 cal BP; 6.5-5.9 ka cal BP, 4.8-4.5 cal BP, 3.3-2.5 cal BP and 1.75-1.35 cal BP. Loss on ignition analyses revealed changes in sedimentation in the landslide mires such as formation of mineral and illuvial horizons in peat sequences, and mineral covers overlying fens, associated with humid climatic phases of the Holocene.