A collection of walks, discoveries, insights and pictures of exploring Dartmoor National Park
March 7, 2025
Xenoliths
A good description of Xenoliths is in ‘Geology Explained: Dartmoor and the Tamar Valley’ by John W. Perkins (1972). Perkins description is : “…pieces of rock which fell into Molten granite. Their chemicals were replaced by those of the granite around then but they can still be spotted by their different grain size”.
The dictionary definition of a Xenolith is a piece of rock within an igneous mass which is not derived from the original magma but has been introduced from elsewhere, especially the surrounding country rock.
Xenoliths exist all over Dartmoor and the author is aware of them at : Blackingstone Quarry, Birch Tor, Braddon Tor, Higher White Tor, Lower White Tor, Blacka Tor, Fur Tor, Hartland Tor, Heckwood Tor and Hamel Down. The list is certainly not exhaustive. This post shows Xenoliths from some of these locations
The author would invite photographic contributions to this post (duly acknowledged of course). Thank you
‘Geology Explained: Dartmoor and the Tamar Valley’ by John W. Perkins (1972) where Xenoliths are discussed. On page 96, John W. Perkins suggests Xenoliths are pronounced ‘Zeen-o-liths’Hoax Tor / Braddon Tor Xenoliths : The author first visited this tor in the late 80’s / early 90’s and knew it as Hoax Tor. Today, it is more usually called Braddon Tor. It has been given other names over the years, such as Rowter Moor Rocks (Hemery). There are at least four Xenoliths hereOn Braddon Tor the Xenoliths are located around the south west outcropLocations of Xenolith’s 1 and 2Xenolith 1 is located at SX62237 79922Xenolith 2 is located at SX62237 79902Close up of Xenolith 2Locations of Xenolith’s 3 and 4Xenolith 3 is located at SX62242 79897Xenolith 4 is located at SX62249 79898Higher White Tor XenolithHigher White Tor Xenolith with Longaford beyondHigher White Tor Xenolith is at SX61955 78571
