Tag Archives: Volcanics

The Wrekin

I’ve chosen for my first post a hill that is close to home.  The Wrekin is one of Shropshire’s most prominent landmarks that’s held in high esteem by many of the locals, including myself.

Location: The Wrekin is found in the centre of Shropshire, less than 1 km south of Junction 7 on the M54.  If you want a geographical coordinate then the top of the hill is about 52*40′ north, 2*33′ west.  To visit it simply turn south off Junction 7 and unless it’s foggy you can’t miss it.

Access: The hill is open to visitors all the time and there is ample parking space.  The path is well marked, but due to some steep inclines people with mobility issues may have problems walking up the hill.  You have two choices when going up the hill.  You can follow the main path that turns left at a hairpin bend up towards a building know as Halfway House or you can take the side path around the hill with the choice of going up the steeper SW slope.  Either are good walks.  At an average walking pace it should take 45mins-1 hour to climb the hill.

Geology: The Wrekin forms a spectacular feature in Shropshire’s landscape and has captured the imagination of the locals for centuries.  Battling giants are included in the myths about its origins, but the real story of its formation is just as epic.  The hill forms part of a geological formation know as the Uriconian Volcanics.  This formation is also responsible for other hills in Shropshire; including Lilleshall hill, the Lawley and Caer Caradoc near Church Stretton.  Sadly despite its name this does not mean that these hills are extinct volcanoes, but rather they are the remains of lava and ash flows from a series of volcanoes long since gone.  The remains of these volcanoes have either been eroded away or deeply buried by younger rocks.  The formation of the lavas that make up these hills is thought to have occurred during a thinning of the crust along with a subduction of a nearby tectonic plate.  A situation similar to the Mount St Helens region of the NW United States.

So how old is it?  The lava flows that make up the Wrekin are between 560-570 million years old, making them some of the oldest rocks in Shropshire.  The hill is made up mostly of Rhyolite, a dark reddish coloured volcanic rock.

DSCF4570Outcrops of the Rhyolite can bee seen on top of the hill, and in some locations (in particular going through the inner gate of the iron-age hill fort) you can see the fine lines in the rock know as flow banding.  This is caused when the slow moving lava stretches out the minerals in it.

DSCF4549Towards the end of the eruption phase a number of intrusive lavas made a series of dykes in the hill.  These are made of dolerite and are a dark black-blue colour.  You can see them at several locations as you walk up the hill where the path turns from a reddish colour to a grey.  One of the best places to see one of the dykes is in the main carkpark at the bottom of the hill.  Between the two halves of the carpark is this formation.DSCF4524

Around the rest of the hill is a mixture of much younger sedimentary rocks; Wrekin Quartzite, Lower Comley Sandstone and the Bridgenorth Sandstones (I’ll go into these another time)

Other Stuff: A side from a look into Shropshire’s volcanic past what else is on the Wrekin?  As mentioned earlier there is the remains of a Hill Fort, first occupied around 3,500 years ago with extensions around 450BC.  The main path takes you up through the both the outer and inner gates.DSCF4544Wildlife is abundant on the Wrekin.  The SE slope is dominated by a mixed deciduous woodland, whilst the NW slope has a pine forest plantation.  There are deer on the Wrekin, and if your’re lucky enough you might catch a rare glimpse of them, along with a wide variety of birds.  Some of the more notable species include nuthatches, treecreepers, ravens, green woodpeckers, buzzards, kestrels and occasionally peregrine falcons.

Overall the Wrekin is a great place for a short walk.  The geology is easily accessible and gives us a fascinating insight into Shropshire’s early history.

Reference: Geology of Shropshire (2nd Edition) by Peter Toghill (2006), The Wrekin Hill by Allan Frost (2007).