{{short description|Unroofed portion of a cavern which reveals part of a subterranean river}} A '''karst window''', also known as a '''karst fenster''', is a geomorphic feature found in karst landscapes where an underground river is visible from the surface within a sinkhole.<ref>{{cite web |url=https://www.speleogenesis.info/directory/glossary/?term=karst%20window |title=Glossary of Karst and Cave Terms: Karst Window |author=<!--Not stated--> |date= |website=Speleogenesis.info |publisher=Speleogenesis |access-date=December 21, 2020 |archive-date=July 30, 2020 |archive-url=https://web.archive.org/web/20200730223920/http://www.speleogenesis.info/directory/glossary/?term=karst%20window |url-status=dead }}</ref><ref>Monroe, W.H., 1970. A glossary of karst terminology (No. 1899-K). US Govt. Printing Office</ref> In this feature, a spring emerges, then the discharge abruptly disappears into a sinkhole. The word ''fenster'' is German for 'window', as these features are windows into the karst landscape.
The term is used to denote an unroofed portion of a cavern which reveals part of a subterranean river.<ref>*Easterbrook, Don J. Surface Processes and Landforms. Upper Saddle River, NJ: Prentice-Hall, Inc, 1999</ref> A complex system of caves, known as karst topography, evolves from the effects of water erosion on carbonate rocks such as limestone, dolomite or gypsum. "A karst fenster is caused by a caving in of portions of the roof of a subterranean stream, thus making some of the underground stream visible from the surface".<ref>*Ritter, Michael E. The Physical Environment: an Introduction to Physical Geography. 2006. Dec 2009.</ref> Theories in the creation of karst topography and karst fensters involve vadose water above the water table, and deep-circulating phreatic water (water in the zone of saturation) eroding away subsurface rock. Karst fensters may also form because of weathering from above.
An example of a karst window or fenster, recognized by the Kentucky Geological Survey, is Short Creek in Pulaski County, where a small river emerges and disappears in a space of less than 100 meters in length.<ref name="KGS">{{cite web |url=https://kgs.uky.edu/kgsweb/download/misc/landuse/pulaski/pulaskiissues.htm |title=Pulaski County, Kentucky |author=<!--Not stated--> |date= |website=kgs.uky.edu |publisher=University of Kentucky |access-date=April 18, 2021 |quote=}}</ref> An example of this formation on public parkland is Cedar Sink in Mammoth Cave National Park, Kentucky, where small watercourses emerge and disappear at the bottom of a large sinkhole.
[[File:OsinskiFig1.pdf|thumb|Illustration of development of karst window by roof rock collapse<ref>*Von Osinski, Wm. "Karst windows." In Proceedings of the Indiana Academy of Science, vol. 44, pp. 161-165. 1934. [https://journals.iupui.edu/index.php/ias/article/viewFile/4676/4528]</ref>]]
==References== {{reflist}} *[http://www.uwsp.edu/geo/faculty/ritter/geog101/textbook/title_page.htm]{{dead link|date=May 2017 |bot=InternetArchiveBot |fix-attempted=yes }}
Category:Karst springs Category:Sinkholes Category:Dinaric karst formations Category:Dinaric Alps
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