Uncovering the Yorkshire Jurassic – May 2018

Yorkshire Museum, Saturday May 19th 2018

“Yorkshire’s Jurassic World” is the first new palaeontological exhibition at the Yorkshire Museum for a good few years, so to celebrate this, and to promote the fabulous Jurassic geology of Yorkshire more broadly, a one-day symposium on Uncovering Yorkshire’s Jurassic was held at the museum on Saturday May 19th. The symposium was organized jointly by the Geology Group of the Yorkshire Philosophical Society, the York Museums Trust, the Yorkshire Geological Society, and the Geology Group at the University of Hull, with additional funding from the Curry Fund.

Catherine Brophy, chair of the Yorkshire Philosophical Society, introduced the day with a welcome from the organizing team, before handing over to Dr Sarah King, Curator of Natural Sciences at the Yorkshire Museum. Sarah has done a terrific job in putting the JurassicYork exhibition together, and explained its aims and origins, emphasizing the importance of bringing together museum collections, curators, researchers and the public. To this end, Sarah has developed the Jurassic Research Yorkshire (JuRY) initiative, with the aim of further developing and strengthening the links between these groups. Museums have a vital role to play in communicating the new research being carried out to as wide an audience as possible.

John Powell (British Geological Survey) then provided an overview of the Yorkshire Jurassic, building on his presidential address to the Yorkshire Geological Society (Powell, 2010). John’s knowledge of the geological variety and value preserved in the Yorkshire Jurassic was amply demonstrated, not least in the region’s building stones. John also revealed why there was once a district of Tangiers called Whitby – apparently a British nobleman was tasked with fortifying the port in 1661 and took a team of North Yorkshire miners and masons to make it happen.

To set the scene for Jurassic environments to come, David Bond (University of Hull) followed up with a review of the end-Triassic extinction event. Few Triassic rocks are exposed in Yorkshire, but research from elsewhere in the world indicates that major volcanic eruptions helped drive climatic and environmental change at this time, on land and in the oceans. The volumes of lava erupted in the late Triassic would have covered Yorkshire in more than 250km of molten rock, Dave revealed.

The Early Jurassic is rather more famously visible in North Yorkshire, enabling Cris Little (University of Leeds) to tell the story of the Toarcian Oceanic Anoxic Event, and how it was not really oceanic or exclusively anoxic, but definitely an event. From the fossil record preserved in the mudstones of Whitby, bivalves in particular show a very rapid extinction and a very slow recovery. Indeed, the marine ecosystems as a whole seem to have taken an incredibly long time to return to their early Jurassic diversity, perhaps as long as 6 million years.

The most famous material from the Whitby Mudstones is surely Whitby jet, and Sarah Steele (Ebor Jet Works & Whitby Museum) provided a fascinating new assessment of this palaeobotanical jewel. Perhaps the most important message is this: IT IS NOT FOSSILIZED MONKEY PUZZLE TREE. Through geochemical and structural analyses, Sarah showed that a variety of trees are involved, and that jet need not even be araucariacean. It is definitely a very oily lignite, and concerns over its provenance and character have led Sarah to develop the new field of hydrocarbon gemmology.

Finishing the morning session, Liam Herringshaw (Hull) dug up the ‘exceptional carrots of Yorkshire’ with a whistle-stop tour of the Kimmeridge Clay Formation, as preserved in the Vale of Pickering, but observed only in French core sheds. Investigation of borehole datasets obtained by the British Geological Survey and French Petroleum Institute in the late 1980s shows that Late Jurassic climatic signals can be correlated in black shales from Dorset to North Yorkshire. A recent study by Armstrong et al. (2016) argues that this reflects strange behaviour in the Inter-Tropical Convergence Zone that seasonally pushed monsoonal conditions as far as 35 degrees North of the palaeo-Equator.

After lunch, Pete Rawson (UCL & Hull) looked back at 200 years of research on the Yorkshire Jurassic, since the ground-breaking work of Young & Bird in 1817. Pete emphasized that there are always new opportunities for important research, not least as storms and wet weather change the exposures along the Yorkshire Coast, and that putting together the latest edition of the GA Field Guide to this region’s amazing littoral geology has only made this clearer.

Inland, the geology isn’t bad either: The North York Moors are a national park after all. Briony Fox (North York Moors National Park Authority) talked through the interactions between the new Sirius Minerals project, aiming to extract Permian salts at depths of well over a kilometre beneath the Moors, and local communities. The project’s mineral transport system will be a 35-kilometre-long tunnel, mainly through the Early Jurassic Redcar Mudstone Formation, and £112,000 has been set aside to help Briony and her team reveal the geology of the North York Moors to the public.

This led neatly onto the day’s final session, as Paul Hildreth (Yorkshire Geological Society) chaired a panel discussion and Q&A, enabling the audience to ask their burning Jurassic questions, and for everyone to debate where to go next. It was apparent that everyone had really enjoyed the day – including some excellent posters on display in the Fairfax Room next to the lecture theatre – and that doing it again sounded an excellent idea. As Middle Jurassic Yorkshire and its tetrapod trace fossils had received relatively little attention this time, they were suggested as a topic to pick up in a future symposium. Until then, it remained only to thank the speakers for speaking, the organizers for organizing, the participants for participating, and the trustees of the Curry Fund for their very kind financial support.

Liam Herringshaw, University of Hull, on behalf of the organizing committee.

A link to the program for the day, with brief extracts on each talk is given below

https://www.ypsyork.org/wp-content/uploads/2018/02/Symposium-Programme-Final.pdf

Some of the speakers were able to offer fuller notes or links to papers covering the ground of their talks as follows:

Sarah King

Yorkshire’s Jurassic World and Jurassic Research Yorkshire (JuRY):

Easter 2018 saw the opening of the first major science exhibition in York for eight years, at the Yorkshire Museum (part of York Museums Trust). Named Yorkshire’s Jurassic World, it explores environments in Yorkshire during the Lower, Middle and Upper Jurassic. The Lower Jurassic gallery explores the deep seas populated by huge marine reptiles, ammonites, belemnites, bivalves and other animals. The Middle Jurassic gallery is filled with dinosaur footprints, vegetation, dinosaur bones and other creatures that would have roamed the coast. This gallery features a Virtual Reality experience with ‘Alan’, recreated from a sauropod vertebra currently recognised as the oldest in the UK. The Upper Jurassic gallery features a rich coral reef environment, and looks at climate and sea level changes. The first gallery is an introduction to the experience, including an opportunity to dig up elements of an ecosystem and interpret these based on the evidence given, as well as an exploration of geology and deep time.

Planned to be in place for around five years, this is a fantastic opportunity to bring the wealth of research into Yorkshire’s Jurassic to the public like never before. This symposium will be the first in a series of events and activities across the life of the exhibition (and beyond) to highlight how important and active research is in this area, and has been ever since the days of John Phillips (the first keeper of the Yorkshire Museum, as well as William Smith’s nephew). Core to the exhibition is a sense of discovery, and how important fossil finds have been for 200 years. We hope The overarching project, known as Jurassic Research Yorkshire (JuRY), will see collaboration from researchers, museums and the public to reinvigorate public interest in this area, and rightfully shout about the fantastic geology on our doorstep and in our museums. This symposium aims to be an introduction to the subject area, touching on various aspects and themes within the galleries, as well as putting Yorkshire’s Jurassic into a wider context. We are aiming for a range of talks, suitable for interested amateurs, and designed to stimulate further interest in this fascinating subject area.

John Powell

A link to his paper is:   http://pygs.lyellcollection.org/content/58/1/21

YGS members will be able to see the whole paper. Non-YGS members will see a much-expanded abstract.

Dave Bond

A link to an open access paper with a major review of all mass extinction events is:

https://www.sciencedirect.com/science/article/pii/S0031018216306915

Section 2.6 examines the End-Triassic extinction. Section 2.7 covers the early Toarcian extinction discussed by Crispin Little in his talk.

Sarah Steele

In mainland Europe we first witness the utilisation of gem quality hydrocarbons for beads and amulets in the Upper Palaeolithic, the period during which our hominid ancestors first developed complex language, culture and art, laying down the foundation for our modern human civilizations. In the British Isles, Whitby Jet, arguably the best quality gem hydrocarbon in the world, first appears in the Early Neolithic. Almost certainly utilised for shamanic ritual, the unique gemmological properties exhibited by members of the jet group make it quite literally a ‘magic’ material. During the Medieval Era these same attributes brought it to the attention of the alchemists as a potential candidate for the ‘Philosophers Stone’.

Despite this illustrious history, very little geological research has been carried out on these culturally important materials, and myth and folk law tend to prevail, rather than hard geological facts. Adding to the problem, a confusion in the nomenclature of gem hydrocarbons has given rise to a situation in which multiple structurally and chemically unrelated materials are often, from an archaeological perspective, termed ‘jet’.

Indigenous jet working communities can still be found in the Americas, Europe and Asia and yet a lack of gemmological research has led to a situation where trading standards authorities are powerless to prevent the illicit commercialisation of foreign materials and simulants sold illegally as indigenous jet.

To better understand these materials Sarah Steele is expanding on the traditional range of gemmological testing methods, and her recent research collaborations with The National Museums of Scotland, The Centre for Research and Restoration of the National Museums of France and The University of Yale are challenging our previous perceptions of Jet. Sarah has recently been appointed Consultant gemmologist at Whitby Museum, England and is currently working to make this work her Ph.D. thesis.

Liam Herringshaw has offered two links

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015PA002911

The online journal EOS published a short article explaining his work in more general terms:

https://eos.org/research-spotlights/simulating-the-climate-145-million-years-ago

Peter Rawson

See his introductory sections to his revised GA guide to the geology of the Yorkshire Coast, (when published).