Friday, 1 March 2013

Karst, clints, grykes and karren

What a lovely selection of words.   All tinny words, not woody at all.   Clints and grykes may be derived from the dialect of Northern England.   Karst almost certainly originated in Slovenia from the Karst limestone plateau.  Definitions as follows:

Karst topography is a geological formation shaped by the dissolution of a layer or layers of soluble bedrock, usually carbonate rock such as limestone or dolomite.

Limestone is slightly soluble in water and especially in acid rain, so corrosive drainage along joints and cracks in the limestone can produce slabs called "clints" isolated by deep fissures called "grikes" or "grykes."

The limestone features described above have specific scientific names and are known as ‘Karren’. Karren is a general term used to describe the total complex of superficial micro-solutional features of soluble rocks such as limestone and gypsum.

These are all terms used in relation to limestone pavements.    Glacial scouring exposed limestone deposited on sea beds around 350 million years ago. Limestone pavements are outcrops of rocks where the exposed surface has been dissolved by water over millions of years into 'paving blocks.' They are also home to a number of rare and unusual plants. Globally they are a rare habitat threatened by extraction for the rock garden and water feature trade and are often degraded by poor land management.

There is very little limestone pavement found anywhere in the world, but Britain and Ireland have much of this habitat.   Limestone pavement is protected by law in the UK and it is an offence to damage or remove it from areas covered by Limestone Pavement Orders.   

Google 'limestone pavements' and click 'images' for an interesting selection of limestone landscapes and read more on limestone pavement conservation here.   Water worn limestone for garden rockeries can still be found for sale and should have been sourced from unprotected areas.   The purchaser will never know whether this is truly the case, unless of course, you buy the lightweight artificial version here:  

The lightweight artificial rockery stone is perfect for green roofs or areas where access is limited.   It's also ideal for display use for nurseries selling alpine and rockery plants.   Water features in the same finish are also available.

A set of nine artificial Westmorland style stones with a three section waterfall.

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