Karst window

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.^[1]^[2] 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.^[3] 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".^[4] 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, County, where a small river emerges and disappears in a space of less than 100 meters in length.^[5] 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.

Illustration of development of karst window by roof rock collapse^[6]

References

^ "Glossary of Karst and Cave Terms: Karst Window". Speleogenesis.info. Speleogenesis. Retrieved December 21, 2020.
^ Monroe, W.H., 1970. A glossary of karst terminology (No. 1899-K). US Govt. Printing Office
^ *Easterbrook, Don J. Surface Processes and Landforms. Upper Saddle River, NJ: Prentice-Hall, Inc, 1999
^ *Ritter, Michael E. The Physical Environment: an Introduction to Physical Geography. 2006. Dec 2009.
^ "Pulaski County, Kentucky". kgs.uky.edu. University of Kentucky. Retrieved April 18, 2021.
^ *Von Osinski, Wm. "Karst windows." In Proceedings of the Indiana Academy of Science, vol. 44, pp. 161-165. 1934. [1]

[2]^{[permanent dead link]}

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[1] "Glossary of Karst and Cave Terms: Karst Window". Speleogenesis.info. Speleogenesis. Retrieved December 21, 2020.

[2] Monroe, W.H., 1970. A glossary of karst terminology (No. 1899-K). US Govt. Printing Office

[3] *Easterbrook, Don J. Surface Processes and Landforms. Upper Saddle River, NJ: Prentice-Hall, Inc, 1999

[4] *Ritter, Michael E. The Physical Environment: an Introduction to Physical Geography. 2006. Dec 2009.

[KGS-5] "Pulaski County, Kentucky". kgs.uky.edu. University of Kentucky. Retrieved April 18, 2021.

[6] *Von Osinski, Wm. "Karst windows." In Proceedings of the Indiana Academy of Science, vol. 44, pp. 161-165. 1934. [1]