We’re just back from a week in Dartmoor, Devon, walking between some of the well-known, usually prominent rocky features of this beautiful landscape, known as tors. 

The Challenge

The tors (there are over 160 of them) are the focus of an annual event known as the Ten Tors Challenge, when around 2400 people aged between 14 and 19 (in over four hundred teams of six), face hikes of 35, 45 or 55 miles (56, 72 or 88km) visiting ten nominated tors over two days.  The teams must be self-sufficient, carrying all that they need to complete their route safely despite the terrain and the weather.  The latter can be very changeable and at times quite extreme, and success or failure can depend very much on the extent to which a team has been trained for all eventualities.

Not having completed this in her youth, my partner ( a local lass), was keen to do her own ‘Ten Tors Challenge’, but at a more leisurely pace. In the event, extremely good weather meant that we were able to visit double the target number of tors spread over six days, and including excellent overnight accommodation at my mother – in – law’s house in Tavistock! Over a series of posts in the next few days, I hope to give an interesting account of our adventures along with a few pictures. For starters here’s a ‘primer’ on Dartmoor and the tors in question….

The Moor

Covering an area of 954 sq km (368 sq miles), Dartmoor contains the largest and wildest area of open country in the south of England. By virtue of its outstanding natural beauty it is one of the National Parks of England and Wales. Unlike many National Parks in other countries, for example the USA, the National Parks in England, Wales and Scotland are not owned by the state.  The term ‘National’ means that they have been identified as being of importance to our national heritage and as such are worthy of special protection and attention.  Within each National Park there are many landowners, including public bodies and private individuals. National Parks are places where people live and work.

Geology

A large part of Dartmoor (65%) is made up of granite, an igneous rock which was intruded some 295 million years ago.  This great granite core is surrounded by sedimentary rocks including limestones, shales and sandstones belonging to the Carboniferous and Devonian periods.  Those nearest the granite intrusion were altered (metamorphosed) by intense heat and pressure and chemical reactions.

Tors

Dartmoor is known for its tors – hills topped with outcrops of bedrock, which in granite country such as this are usually rounded boulder-like formations. More than 160 of the hills of Dartmoor have the word tor in their name but quite a number do not.   However this does not appear to relate to whether or not there is an outcrop of rock on their summit.

The processes resulting in the formation of the Dartmoor tors started about 280 million years ago as the granite forming Dartmoor cooled and solidified from molten rock at a temperature of 900 – 1000˚C. The minerals which make up granite crystallised as closely interlocking grains forming the hard rock. Granite is formed of three main minerals: Quartz – appearing in the granite as translucent slightly greyish looking grains; Feldspar – white grains, sometimes stained yellowish or pink (in parts of the granite feldspar forms large white crystals); and Biotite – dark brown glistening flakes.

Varying climatic conditions occurring over millions of years, along with the cooling of the molten and other materials were the first, mainly chemical factors in the formation of the tors. Most recently, cold conditions in the Ice Age (between 2 million to 10,000 years ago), have caused major mechanical forces to shape the landscape we see today. Of these the most important is the expansion of freezing water. The deeply weathered granite was forced apart and broken up into blocks by being subjected to frequent freezing and thawing during the cold periods of the Ice Age, and gravity was also important, moving the loose material downhill.

 The principal tors are:

Well that’s the basics….except you might be interested in a TV programme that is showing this evening (Tuesday 9th September) on ITV 1 (7.30pm). The first in a new series of ‘Wilderness Walks’ by bushcraft expert Ray Mears focuses on Dartmoor. I’ll certainly be watching….

…so now for an article on the first stage of our trip – and it’s a mysterious beginning to our adventure that awaits…..(I’ll explain more about the nudist along the way too).

Further Information:  Dartmoor National Park

Old School Gardener