A Little Contribution to the Karst Terminology: Special or Aberrant Cases of Poljes?

Abstract

UDC: 551.44:001.4 Jean Nicod: A little contribution to the karst terminology : special or aberrant cases of poljes? A usual definition of polje states that it is "great closed karst basin with flat bottom, karstic drainage and steep peripheral slopes". But the Dinaric karst shows a wide range of poljes. The article discusses the main criteria of polje definition and the different degrees of evolution of the polje are emphasised. The essentials are gathered in the table with new tentatives on classification of poljes and comparing the Dinaric karst with other Mediterranean and Alpine countries.

Geomorphological evolution of the Vendicari karstic coastal lake system (SE Sicily, Italy)

“…The sequence of four-stepped levels of corrosion surfaces represents alternating periods, some of them dominated by deepening and others by planation and expansion of the polje bottom, always controlled by the position of the water table. In coastal environments poljes can develop seasonal or permanent lakes, according to sea level (Bonacci 1987;Nicod 2003).…”

“…In the description and classification of poljes made by Gams (1978) intermediate terms can be found, like uvala-like-polje, polygenetic polje or compound polje. Nicod (2003) indicates that some poljes may proceed from connection of previous uvalas. Diagnostic indicators of poljes with respect to uvalas are: flat bottom (uvalas usually have uneven bottom), karst inflow and outflow, terraced corrosion levels, steep slopes surrounding the bottom, tectonic origin or control and relationship with water table, among others.…”

“…A discussion about this topic can be found in Frelih (2003). An additional diagnostic indicator in favour of the polje hypothesis is the recognition of cryptocorrosion markers, since cryptocorrosion is a genetic process typical of poljes (Fabre & Nicod 1982;Nicod 2003): hohlkarren, kluftkarren, etc., are very different from the typical coastal phytokarst micromorphologies (Ford & Williams 2007). The absence of these cryptokarren morphologies does not discard the polje hypothesis, but their presence is an argument in favour of the latter.…”

Polyelerin Sınıflandırılması ve Toroslardan Örnekler

“…Zaman zaman polye tabanı ya da kenarındaki düdenler bitki parçaları gibi çeşitli malzemeler veya kil ile tıkanabilir bu da polye tabanında geçici/kalıcı göl oluşumu sağlar (Bonacci, 2013). Bu gölsel koşullar iklim salınımlarına (Doğan, 2003;Doğan ve Koçyiğit, 2018), deniz kıyısındaki polyeler ise deniz seviyesi değişimlerine (Nicod, 2003) göre değişebilir. Tabanı geçirimsiz formasyonlardan oluşan ya da geçirimsiz alüvyal malzeme ile kaplanan polye tabanlarında biriken sular ya da polyeyi kat eden akarsular, polye yamaçlarını alttan aşındırarak geriletir (örn.…”

“…Polye tabanlarında yanal karstik gelişimi gösteren çözünme artığı hum tepeler oluşabilir. Bir polye dış drenaja açılırsa artık karakteristik bir polye olma özelliğini kaybeder ve fluvio-karstik vadi (Doğan, 1996), fosil ya da açık polye olarak kabul edilir (Nazik, 1992;Nicod, 2003). Polyeler daha çok kireçtaşı arazilerinde yaygın olarak görülse de, nadir olsa da jips arazilerinde polye benzeri oluşumlara rastlanır (Doğan & Özel, 2005).…”