Saturday, 28 June 2014

A short story about Karst Limestone Landscapes

The Hotel built on a limestone outcrop
Lime stone is the rock that predominates in Asturias and The Picos de Europa are a geological unit composed almost purely of limestone and are the largest single mass of mountain limestone in Europe. The hotel is actually built on a limestone outcrop and this limestone becomes very noticeable in the upper part of our farm; but have you thought about what limestone actually is?

Limestone in the Picos de Europa
Limestone is a sedimentary rock composed from skeletal fragments of marine organisms (calcium carbonate minerals) such as coral or foraminifera shells. Yes that’s right; this means that the rock underneath the hotel and the soil on the hotel farm was made from shells of animals that once lived at the bottom of the ocean. A billion year history through the movement of tectonic plates brought these rocks high above the ocean, where we stand today.

Limestone rocks in the top part of the hotel farm

Limestone rocks in the Picos 
However the story of this mother rock doesn't stop here, it's the relationship of limestone with water that leads to these so called "karst landscapes", water eroding limestone over thousands to millions of years. The landscape at the top of the farm is very similar to the one in many parts Picos the Europa. Almost all of the rock in the Picos is limestone, and glacial action has contributed to create an impressive area of alpine karst. 

Flutes or pencil karst in The Picos
The mysterious stories of karst affect not only the rock that you can see, it also happens underneath the dark soil where we can't see. Above sink holes, flutes, runnels, vertical shafts, clints and grikes are some of the most visible features on the surface of the terrain.  Beneath the surface, complex underground drainage systems (such as karst aquifers) and extensive caves and cavern systems form a mysterious underground world.

Blow holes in the limestone at the coast near LLanes
Limestone eroded by the sea
As for all the inhabitants of this landscape, farmers in karst areas must take into account the lack of surface water. The soils may be fertile enough, and rainfall may be adequate, but rainwater quickly moves through the crevices into the ground, sometimes leaving the pastures parched brown between rains. 

Parched landscape near Vega Ario in the Picos
A delicate and precise management of the land makes this unique place a living museum. Here the most outstanding geological sculptures are married with a sustainable farming system that brings to life a cultural conservation of nature.

Geological sculptures in the hotel farm
This blog entry is based on text for a farm poster written by Sebastian Burch co founder and worker at Gaia y Sofia

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Hotel Posada del Valle is a small hotel in Asturias Northern Spain surrounded by its own organic farm and where we are passionate about organic farming, food, and sustainable livelihoods. In this Blog those of us who live and work at Hotel Posada del Valle open a door to share with all of you who are interested in what we are doing.