County Durham’s tropical seashore?

QuarringtonHill

The Magnesian limestone escarpment, looking north from Bowburn.

The village where I live is overlooked by the Magnesian limestone escarpment formed from a coral reef dating from the Permian era.   On cold winter days I get a perverse pleasure from contemplating this escarpment and mentally transporting myself to a balmy tropical beach beside the Zechstein Sea, 250 million years ago, watching the trilobites scuttle around in the shallows.

The Magnesian limestone extends about 20 kilometres east from here, ending at the Durham coast where there is some classic limestone coastal scenery You may have encountered this coastline before as Easington, a few kilometres to the north, was the setting for the film Billy Elliot and the closing sequence of the 60s thriller Get Carter were also filmed here. Both of these films refer back to Durham’s mining heritage. Now, however, the pits have all closed and the area’s natural beauty is able to flourish once again. There are some unique limestone grassland communities associated with the Durham coast, with orchids and primroses abundant in the spring.

It was, however, far from spring-like when I visited last week, with a biting wind blowing in from the North Sea. The clear skies, however, gave some spectacular views. Looking north, I could see almost the entire Permian coastline, as far as the headland at Souter, just south of South Shields whereas in the other direction I could see the industrial sprawl of Teeside and, beyond it, the North York Moors south to Whitby. About 80 kilometres of coastland were on display from the beach at Blackhall.

Blackhall_Rocks_Feb2015

Looking north along the coast at Blackhall Rocks on a cold February day.

My interest in Blackhall lies in the particular type of limestone that is found here.   The technical term is the “Hesleden Dene biostrome” and, looking closely, I can see within it some finely laminated horizontal layers within the rock, each no more than a millimetre thick, that are formed from layers of filamentous blue-green algae, such as those we have seen in the River Ehen and elsewhere, albeit marine rather than freshwater, that gradually accumulated on the shallow bed of the tropical sea that I fondly dream about.   They are often flat, as in the picture below, but sometimes form mounds and hummocks reminiscent of the stromatolites that I wrote about recently (see “The origins of life …”). The twenty kilometres I travelled from my home to Blackhall is also a journey back 250 million years, well before the age of the dinosaurs. Yet it is also a reminder of a yet more ancient world, that of the Precambrian where the earliest fossils of stromatolites have been found. That requires us to repeat the 250 million year journey to the Permian about six more times to take us back 1.5 billion years to the middle of the Precambrian.

Hesleden_Dene_biostrome

Laminated strata of fossilised algae in the Hesleden Dene biostrome at Blackhall Rocks.  

I’ve known about the fossil algae at Blackhall for a long time and they were even the subject matter for a piece of video art I produced whilst doing my Fine Art degree (fear not .. the file is far too large to consider uploading).   Whilst searching the internet for information to refresh my memory I happened upon a resurrected online edition of The Vasculum. This was a local natural history journal produced by the Northern Naturalists Union, which thrived on contributions by both amateur and professional ecologists. During my time as a postgraduate student, Tom Dunn, the editor (and an enthusiastic lepidopterist) would prowl the corridors of the Botany and Zoology Departments at Durham making sure that we had all paid our subscriptions.   I had thought that The Vasculum was one more victim of our gradual slide towards a culture of armchair naturalists so I was delighted to see that it is now thriving in a new, online format. Long may it last.

Reference

Birtle, M. (2012). The Permian landscape of the north-east coast in 2012. The Vasculum 97: 1-32.

See also: Blackhall Rocks (GCR ID: 3016) In: Volume 8: Marine Permian of England, Chapter 3: North-east England (Durham Province), Geological Conservation Review, JNCC

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“They don’t do much, do they?”

I spent the early part of yesterday evening listening to Richard Fortey talk on “Survivors: the animals and plants that time has left behind” at Van Mildert College in Durham.   Fortey is a palaeontologist, best known for his work on trilobites, but who has also presented popular television series on natural history topics.   In this lecture, he talked about the small number of organisms that were well represented in the fossil record (some pre-dating dinosaurs) yet which had survived the various mass extinctions and which could still be found today. Did these organisms have anything in common, he wondered.

One group of organisms that he talked about were the blue-green algae (Cyanobacteria) responsible for forming “stromatolites” which are found both in Precambrian rocks over a billion years old and in a few locations today.   I’ve talked about blue-green algae in many of my posts (e.g. “More reflections from the dawn of time …”) but what amused me this evening was Richard Fortey’s anecdote about a discussion with a BBC producer as they devised a television series based on his book:

Fortey: “These are the most important organisms in the history of the earth” (commenting on their role in creating the oxygen-rich atmosphere that every organism since has relied upon)

BBC producer: “they don’t do much, do they?”

It is a subject that I have addressed several times in this blog (see “The sum of things …”, “Every second breath …”): how do we address the imbalance in natural history broadcasting between the charismatic “few” and the unfashionable “many”, bearing in mind, of course, that these are, in many cases, the hard-working, unglamorous “back office staff” who keep our planet running.   Television natural history programmers are in the entertainment business first and I’m not going to pretend that a stromatolite made of blue-green algae is, on its own, a recipe for compelling television.   But I also feel that there are possibilities that could be explored, and that we may be held back by a lack of imagination on the part of broadcasting creatives and commissioning editors.   They, too, are children of the television age, brought up on a style of broadcasting from Zoo Quest through Life On Earth and onwards that is interested only in the televisual aspects of natural history. Whoa .. hold it there … I’m coming dangerously close to criticising David Attenborough … Saint David … that’s close to heresy.

Reference

Fortey, R. (2011). Survivors: the animals and plants that time has left behind.   Harper Collins, London.