Health & Safety

Steeply sloping ground, precipices and rock fall hazards

Geologists often work in very isolated and hazardous places, where there are precipices and dangers of falling rocks, steep and often unstable or slippery slopes, boggy ground and water hazards – amongst others.

Water Hazards, Bogs and Quicksand

As an undergraduate, whilst mapping the Borrowdale Volcanics near Keswick, I became very aware of this when, walking on the moors, I stepped into a deep boggy hole that came up to my thigh. Having spent a few weeks safely traversing the rugged terrain, it took me completely by surprise and I could easily have broken my leg. 

By myself, and in the days before mobile phones, only the sheep and their Welsh Border Collies could have possibly been within hearing range.

No doubt, the codes of practice for undertaking fieldwork have changed considerably since this time; however, other minor accidents - experienced or witnessed whilst working on scaffolds in the construction industry and cutting stone in a quarry - have reinforced my own common sense attitude towards Health & Safety.

Quarrying, stonemasonry and landfill

Both Martin Said and Marc Voltaire had undertaken preliminary visits and produced risk assessments of potential sites for the XP School “Rock On!” project and I thought that the places that we had visited on Day 1 were low risk, as far as safe access to these was concerned.

Knowing potential field trip hazards well, the students were being thrown in at the deep end to a certain extent but, when everyone decided to go to North Cliff Quarry on Day 2, we agreed that it is very important to be aware of personal and collective Health and Safety issues at an early age.

A Permian Bryozoan Reef at Hooton Pagnell

A Permian Bryozoan Reef

A Permian Bryozoan Reef

Whilst surveying a wide variety of natural landforms and active and redundant quarries in South Yorkshire, I have seen many ancient bryozoan reefs and, the Yellow Sands Formation excepted, I think that these are the most interesting rocks that can be found in this region.

A detail of the Permian reef at North Cliff Quarry

At North Cliff Quarry, one of these reefs overlies massive beds of buff coloured, cross bedded, oolitic dolomitic limestone that is full of of small bivalve fossils - often preserved as moulds - giving the rock a porous texture that distinguishes it from the beds that lie above and below them. 

The lower section of the reef mass is partially brecciated - often with a distinct reddening of the fine grained matrix, which provides evidence of the influx of muddy sediments similar to those found in the Permian marls.

From paths running along the top of the various quarry faces, there are also excellent views of the scarp and dip topography of the Coal Measures strata to the west, the limestone escarpment to the north and the Don Gorge to the east.

Like so many old quarries, North Cliff Quarry has attracted dirt bike riders and has been a dumping ground for cars. When I last visited the site, in 2007, bottles and cans and miscellaneous rubbish littered the place; however there was still easy access to most of the rock exposures.

 

A few views at North Cliff Quarry

A Lesson Learned

Rock Art

 

When a shortlist of 4 sites was selected by the teachers leading the XP School “Rock On” project, I did have some reservations about going to Barnburgh Cliff, as I thought that the students would not have enough time to fully appreciate the points of interest here.

A view of the Dearne Valley in 2007

Although the geology is excellent, and the geomorphology of the Dearne Valley can be appreciated here, it is relatively remote and it takes a moderately long walk before the Carboniferous sandstone and the best exposures of the Permian limestone can be seen.

When I visited this site in February 2007, various geological features could easily be observed on a cloudy day.

An exposure of a Permian reef in 2007

Making up for time lost at Cedar Road Quarry, the students concentrated on the measuring and drawing tasks at Warmsworth Park and, by the time we arrived at Barnburgh Cliff, we only had 15 minutes to explore the site - before the group had to get back to school.

As the students jogged past the bryozoan reefs, I noticed that the undergrowth appeared to be much more hazardous and all of the rocks looked very dark and dank - beneath a dense canopy of leaves.

Stopping at a cave, I was asked to give a short explanation of the geology that the students could see behind me and then we had to leave, and I didn't take a single photograph.

On the way back to the minibus, a couple of the students – including one who was fascinated by the rocks at Cedar Road Quarry – told me that they had thought that rocks were all the same, and very boring, but that they were now much more interested in them. They had also noticed the Rock Art that can be seen here...

Dolomitic limestone and a sand filled rift  in 2007

Carboniferous Sandstone

An outcrop of Carboniferous sandstone

The survey of potential RIGS in Doncaster in 1997, like others in the rest of the county, was based on information gleaned from old maps, geological memoirs and local knowledge of the area. For some reason, Barnburgh Cliff was not identified during the desk top study and I first saw this site in 2007, when temporarily working with the British Geological Survey to produce the Doncaster Geodiversity Assessment.

Permian dolomitic limestone

Walking through a plantation along a straight bridleway, with a continuous exposure of well bedded dolomitic limestone up to 4 metres high - on one side - I thought that this place must have been quarried as a building stone at some time; it has been suggested that a Roman road passed closely by.

It is a very good place to examine the lowest parts of the Cadeby Formation - with its shelly ooid-limestones and reefs - which has a totally different character to the Sprotbrough Member seen at Warmsworth Park.

The yellow colour of the limestone often coincides with the appearance of large fissures, parallel to the rock face, filled with orange coloured sand of Quaternary age. Some of these have developed into small caves, which elsewhere in South Yorkshire have been investigated by speleologists, and which are the home for various species of bats. 

Although the Permian limestone contains some very interesting geological features, Barnburgh Crags is one of the very few places that I know of in South Yorkshire, where the underlying Carboniferous rocks can also be seen at the same locality. Unlike Ashfield Brick Pit, which as a SSSI was controversially infilled, the exact position of the unconformity that separates these geological periods can only be inferred from field evidence – but it is still an excellent field trip locality, at all levels of study.

Upper Carboniferous Sandstone