Acta carsologica

0145287 - GLU-S 20013072 RIV SI eng M - Monography Chapter
Bosák, Pavel
The evolution of karst and caves in the Koněprusy region (Bohemian Karst, Czech Republic), Part III: Collapse structures.
Acta carsologica. Inštitut za raziskovanje krasa, s. 35-50
Institutional research plan: CEZ:AV0Z3013912
Keywords : paleokarst * hydrothermal karstification * collapse
Subject RIV: DB - Geology ; Mineralogy
https://ojs.zrc-sazu.si/carsologica/article/view/447

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.
Permanent Link: http://hdl.handle.net/11104/0042897