Soft-sediment deformation structures in cave deposits and their possible causes (Kalacka Cave, Tatra Mts., Poland)

0541402 - GLÚ 2022 RIV GB eng J - Journal Article
Szczygieł, J. - Wróblewski, W. - Mendecki, M. - Hercman, H. - Bosák, Pavel
Soft-sediment deformation structures in cave deposits and their possible causes (Kalacka Cave, Tatra Mts., Poland).
Journal of Structural Geology. Roč. 140, November (2020), č. článku 104161. ISSN 0191-8141. E-ISSN 1873-1201
Institutional support: RVO:67985831
Keywords : Cave sediments * Liquefaction * Site effects * Palaeoseismicity * Tatra mountains
OECD category: Geology
Impact factor: 3.571, year: 2020
Method of publishing: Limited access
https://www.sciencedirect.com/science/article/pii/S019181412030081X

Clastic deposits in Kalacka Cave in the Tatra Mts. Show soft-sediment deformation structures (SSDS) rare for a cave environments. The poorly sorted allochthonous sediments were deposited within a cave sump under a fluvial regime, likely due to glacially initiated back-flooding during the Last Glacial. The structures include smallscale faults (normal and reverse), folds (upright symmetric anticlines, low-amplitude open folds, W-vergent folds and fault-propagation folds), and water-escape structures. A laboratory experiment is used to assess the possibile liquefaction of a thin soft-sediment filling in a limestone tube, including calculation of the site effects of resonance frequency and amplification coefficient and the site vulnerability index Kg. The calculations indicate that seismic waves can be amplified up to 10 times and the expected resonance frequency is ~17.05 Hz. We argue that the observed SSDS formed in two stages. First, brittle and ductile deformation structures developed due to gravity-induced slumping. Next, liquefaction produced water-escape structures. The studied SSDS were likely seismically triggered. Favorable conditions occurred during the withdrawal of the last glacier (MIS 2) when the sediments were oversaturated and the Tatra Mts. experienced a strong earthquake (M7.0). Alternatively, high-frequency microearthquakes could have been triggered by slope failure cutting into Kalacka Cave.
Permanent Link: http://hdl.handle.net/11104/0318962