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Acta carsologica
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SYSNO ASEP 0145287 Document Type M - Monograph Chapter R&D Document Type Monograph Chapter Title The evolution of karst and caves in the Koněprusy region (Bohemian Karst, Czech Republic), Part III: Collapse structures Author(s) Bosák, Pavel (GLU-S) RID, SAI Source Title Acta carsologica. - : Inštitut za raziskovanje krasa - ISSN 0583-6050 Pages s. 35-50 Number of pages 16 s. Language eng - English Country SI - Slovenia Keywords paleokarst ; hydrothermal karstification ; collapse Subject RIV DB - Geology ; Mineralogy CEZ AV0Z3013912 - GLU-S UT WOS 000080470800003 DOI https://doi.org/10.3986/ac.v29i2.447 Annotation Vertical and subvertical pipes are circular to ovate in shape with diametres from 2-4 m up to tens of metres and with proven depth up to 82 m. Some of them terminate by horizontal cave levels at depth. Pipes are filled with complicated sedimentary sequences with clearly developed collapse structures. The fill is composed of pre-Cenomanian, Cenomanian-Turonian and Tertiary deposits. Internal structures of the fill indicate multiphase collapses. Cretaceous and pre-Cretaceous deposits are often subvertical with chaotic internal texture. In the centre of some of pipes, there are traces of younger collapses, most probably induced by continuing karstification and suffosion at depth. Tertiary deposits overlay the Cretaceous ones unconformably; they show gentler centripetal inclination, but in places they fill the central parts of collapsed fill. The origin of solution pipes is connected with hydrothermal activity most probably during Paleogene to Miocene, when the surface of limestones was still covered by slightly eroded cover of Upper Cretaceous platform sediments. Hydrothermal karst forms developed up to the surface of limestones as the piezometric level was situated within the Cretaceous cover. After the lost of buoyancy support of water, sedimentary cover started to move (collapse) down. Workplace Institute of Geology Contact Jana Popelková, popelkova@gli.cas.cz, Tel.: 226 800 273 Year of Publishing 2002
Number of the records: 1