back to main menu links to relevent geological sites

CAER CARADOC

Caer Caradoc is one of the Stretton Hills.  It helps to make the east slope of the Stretton Valley opposite the Longmynd

It makes a very good view point and to add further interest there is also an Iron Age fort on the top

This part of Shropshire during the late Precambrian was at the margins of an ocean where two tectonic plates were coming together.

The plate to the west (as it it today, towards Wales) was moving into the plate to the east (in the West Midlands). Their zone of contact was in the vicinity of the present-day Stretton Valley, along a gigantic crack through the Earth's crust that we now know as the Church Stretton Fault Zone. In fact there are a whole series of cracks that make up the Fault Zone, and Caer Caradoc lies between some of them ('F1' to the west (top) and 'F2' to the east; a further fault, 'F3', lies still further east). Edgar Cobbold in his retirement produced a remarkable map of this area, published in 1927 and reproduced here with kind permission of the publishers: the Geological Society of London (who retain the copyright). This work was greatly facilitated by Cobbold's local contacts and his friendships with local farmers, persuading many of them to dig pits in the places where he wanted to see the underlying rocks - a luxury not usually furnished to geological investigators!

The westerly plate sank beneath the easterly one and as it did so the sediments became piled up, forming the thick sequence we see today within the Longmynd.

 

 

 

 

 

Looking down into the Stretton Valley from Caer Caradoc it is hard to believe that you are looking at a tear in the Earth's crust, a fault line that was once as active as the famous San Andreas Fault in California!

As the westerly plate sank deeper into the mantle so the heat caused partial melting and volcanoes developed above, within the easterly plate. Their lavas and intrusions formed the rugged crags of Caer Caradoc and its associated hills. However, the volcanoes released a lot of ash and this accumulated as beds within the sedimentary sequence, known as Tuffs.

click an icon to find out more
about the geology of this site

BACK TO TOP 20 MAP (SOUTH) BACK TO TOP 20 LIST BACK TO SHROPSHIRE GEOLOGY INTRO