In 1997 Horbury Quarry was designated a Local Geological Site by West Yorkshire RIGs group later known as the West Yorkshire Geology Trust. Using guidance from DEFRA the group of volunteers, mostly amateur geology enthusiasts, surveyed the districts of West Yorkshire to find the most suitable sites to designate as RIGS (Regionally Important Geological/Geomorphological Sites) which are now known as Local Geological Sites. Sites were selected on the basis of various criteria, generally related to their suitability for educational use, their accessibility and their scientific value. In total the West Yorkshire Geology Trust identified and listed a total of 69 RIGS spread across the five districts of West Yorkshire.
In Horbury Quarry exposures of Horbury Rock Sandstones of Upper Carboniferous (Middle Coal Measures) age are revealed in a 15m high abandoned quarry face. The 100m long exposure illustrates a range of sedimentary features, including cross bedding, jointing, leisegang rings and iron nodules. The rock is fine-grained and well-cemented, exhibiting massive, blocky and flaggy bedding. Whilst the eastern section of the exposure is well bedded, the western end of the site shows a transition toward more fracturing and irregular jointing. The Quarry Inn is built at the eastern end and has a small rock face in the car park which shows some interesting structures.
In order to qualify for this earth cache the following questions must be correctly answered and emailed to the CO before a found log is posted. Any logs which do not meet this criteria will be deleted
- In what geological period was the Horbury Rock Sandstone formed?
- Name 2 sedimentary features visible in the rock face?
- What are leisegang rings?
- How high approximately is the quarry face at the eastern end?
- Describe the picture on the Rock face at the eastern end.
- Optional: Post a picture of yourself with your GPSr and the quarry face in the background