Thank you very much Steffi and Jesko for sending this card from the Krkonoše National Park, Czech Republic. This relatively small mountain range is located on the Czech Polish Border.
This beautiful area is popular with tourists from all over Europe, there is plenty of information about it here, including some incredible images of the landscape.
The rock formation shown in the following photograph is called a tor and there are several examples in Krkonoše:
This tor, and others like it, is granite rock. The granite was forced inbetween existing rock layers as an igneous intrusion. Imagine you have a syringe full of strawberry jam and you insert the needle into a sponge cake. Then you squeeze down the syringe; the jam squirts into the sponge. The molten granite was squeezed into the pre-existing layers of rock by the force of the heat and pressure of the mantle (below the earth’s crust). When it was squeezed in the granite was extremely hot, but gradually it cooled and eventually became solid rock. The process of cooling caused some contraction and this caused the rock to crack into tightly packed blocks.
Many millenia passed and finally the overlying rock is weathered and eroded away, leaving the more resistant granite as these high towers poking above the rest of the landscape. The removal of the weight above releases some of the pressure on the granite and some horizontal cracks break at this point. The breaks in the granite are now exposed to the elements and become vulnerable to weathering themselves. This emphasises the joints and cracks, giving the tors their unique appearance.
Tors can be found elsewhere too, the example below is Haytor in Dartmoor, England:
If you would like to find out more about these striking outcrops check out Dartmoor National Park’s factsheet.