Eye opening fossil deposits

Anomalocaris reconstruction c. Katrina Kenny, University of Adelaide

Anomalocaris reconstruction c. Katrina Kenny, University of Adelaide

The Journal of the Geological Society’s series of ‘Review Focus’ articles on fossil Lagerstätten continues with recently discovered fossils from Emu Bay, South Australia, which are casting new light on the early evolution of vision…

The finds, recently reported in the Journal of the Geological Society, provide insights into the ‘Cambrian explosion’ – a period of rapid diversification of multicelilar organisms that began around 542 million years ago.

Over 50 species are recorded from the Emu Bay Shale biota, 70% of which are entirely soft-bodied. The fossils include trilobites, sponges, molluscs and anomolocaris – large, shrimp like predators also found in the Burgess Shale and Chengjiang formations.

Similar in age and biota to other Burgess Shale-type assemblages, the EBS are preserved in a different way.

‘Typical Burgess Shale type deposits contain fossils that are preserved as two-dimensional carbon films’ says Professor John Paterson of the University of New England’s Palaeoscience Research Centre, who co-authored the paper. ‘Emu Bay Shale fossils are different in that there are no remnants of carbon film – though this could be explained by the extensively weathered rocks.

Redlichia takooensis c. John Paterson

Redlichia takooensis c. John Paterson

‘But it is the 3D nature of the specimens that really sets them apart. This requires further investigation, but one explanation might be the slightly coarser-grained sediment, in contrast to the clay-rich sediment of other Burgess Shale type deposits.’

They also differ in the location in which the animals would have lived – very close to shore, in contrast to Burgess Shale type deposits which formed further out to sea.

Buck Quarry panorama c. John Paterson

Buck Quarry panorama c. John Paterson

‘Although it was probably a deep water environment, much of the water column in which many of the animals would have been swimming was well lit’ says Paterson.

‘The seafloor was a much harsher environment due to the low oxygen levels, and only those organisms that could tolerate such conditions, such as worms, sponges and some trilobites, were living on a murky, muddy bottom.’

The fossils include examples of arthropod eyes – some with unusually detailed preservation.

‘The spectacular compound eyes that have been found in the Emu Bay Shale are preserved in such detail because these organs that were originally composed of chitin were replicated by inorganic minerals during the very early stages of the fossilisation process’ says Paterson.

Anomalocaris eye c. John Paterson

Anomalocaris eye c. John Paterson

‘In the case of the Anomalocaris eyes, chemical reactions transformed them into pyrite  (or ‘fool’s gold’), which later ‘rusted’ to form iron oxide.

‘These discoveries tell us that powerful vision evolved rapidly during the early Cambrian.’

These chemical reactions, producing minerals that can replicate delicate tissues such as muscle fibre and digestive glands, are part of the reason the fossils show such exceptional levels of preservation. Added to this, the environmental conditions at the time, which helped delay the decay of the organisms. Says Paterson:

‘There is evidence to suggest that many of the species were either swept into or settled down on a part of the seafloor that was very poorly oxygenated. The lack of oxygen slowed the microbial decay of carcasses and most likely inhibited scavengers from disturbing the bodies before and during burial. This explains why many of the soft-bodied animals, such as worms – otherwise rare in the fossil record – are preserved in such exquisite detail.’

There is much more to be discovered from the Emu Bay Shale fossils, which first began to be uncovered in 1954, when large specimens of the trilobite Redlichia were discovered.

‘We would like to know a great deal more about the processes leading to the exceptional preservation of the fossils’ says Paterson, ‘particularly why the soft-bodied fossils have a 3D aspect and commonly show a variety of anatomical structures that have been replicated by different minerals. This combination of features is rather unusual when compared to other Burgess Shale type fossil sites.

‘To better understand this, we will be focusing on the sedimentologic and geochemical evidence from the Emu Bay Shale.’

  • Journal reference:

John R Paterson, Diego C. Garcia-Bellido, James B Jago, James G. Gehling, Michael S Y Lee & Gregory D Edgecombe, ‘The Emu Bay Shale Konservat-Lagerstätte: a view of Cambrian life from East Gondwana’., Journal of the Geological Society, first published online 10 November 2015 http://jgs.lyellcollection.org/content/early/2015/10/29/jgs2015-083.abstract

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The 2015 Joint Regional Group Photographic Competition

c. Malcolm Nugent ‘Etna Beneath our Feet.’

c. Malcolm Nugent ‘Etna Beneath our Feet.’

There’s just under 2 weeks left to enter the 2015 joint photography competition, organised by a number of our Regional Groups! Continue reading

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100 Great Geosites calendar!

100GG Badge CMYK-white-backgroundFollowing the announcement of our recent photography competition winners, our 100 Great Geosites 2016 calendar is now on sale!

CoverFeaturing high quality prints of the 13 winning images (12 months plus a cover), and geological descriptions of each featured site, the calendar is A3 size and priced £7.50.

Sites included in the calendar range from beautiful geological landscapes such as the Giant’s Causeway and Durdle Door, to visitor attractions including the Rotunda Museum and Marble Arch Caves. Continue reading

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The 2015 Geoscience Education Academy

A guest post from Natasha Cowie. Natasha has just finished her GCSEs and plans to read geology at University, and hopefully enter the field afterwards.

Natasha Cowie 3

Natasha (foreground) with some participants of the Geoscience Education Academy

I was probably around 8 years old when I began to make a small collection of different rocks that I found when my family and I went on our summer holiday to Pembrokeshire, Wales. Back then, I didn’t realise what I was doing, but as I grew older and learned more I discovered my love of rocks.

My interest continued during my Geography GCSE, where I learned more specifics, and how to tell the difference between different rock types. It wasn’t until I had to choose my A-levels that I realised geology was what I really wanted to pursue. Continue reading

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From the archives: Halloween special

On the eve of All Hallows’ Eve, we revisit a spinechilling post from the blog vaults….

Originally published on December 19th, 2013, our archivist Caroline Lam tells the spine chilling tale of GSL Fellow Dr J W Webster, ‘whose name was ordered to be erased’…

John_White_Webster“In December 1814, the Society established a ‘Foreign Member’ category of honorary membership.  As the name suggested, the title was limited to non UK individuals.  Those eligible should be ‘Distinguished mineralogists and persons who had by their communications or contributions promoted the objects of the Society’.

As most Foreign Members were elected in absentia, it is likely that many had not and never would set foot inside the walls of the Society.  This was not the case with John White Webster. Continue reading

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The 26 October 2015 Afghanistan Earthquake

Image c. USGS

Image c. USGS

At 09:09 (GMT) on Monday 26 October a magnitude 7.5 earthquake hit the north-eastern area of Afghanistan near the Tajikistan and Pakistani border. It occurred as the result of reverse faulting approximately 210 km below the Hindu Kush Range of mountains in Afghanistan. Continue reading

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The 100 Geosites Photo Competition

Earth Science Week Geological Time combo





Just before the start of Earth Science Week 2015, we announced the results of our 100 Great Geosites photo competition – 13 images which form a 2016 calendar now on sale at the Society!

Last night, at the launch of Earth Science Week, we were thrilled to present awards to 4 of the photographers who were able to join us – Caitlin Broadbent (Durdle Door), Steve McAusland (Lundy Island), Anna Saich (Seven Sisters & Beachy Head) and Louise Squire (Staffa).

calendar winners

The four winning photographers, with GSL Executive Secretary Sarah Fray (centre)

We also announced the top three winning photographs: Continue reading

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Earth Science Week – Ask a Geologist live!

Earth Science Week Geological Time




Earth Science Week 2015 is already underway, and as per tradition, we will be hosting #askageologist sessions on twitter every day with five brilliant scientists. All you have to do is use the hashtag to ask them your questions! If you don’t tweet, or can’t be there for the live session, send us your questions using the comments form below, and we’ll make sure they get answered. Continue reading

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100 Great Geosites photo competition – the results!

100GG Badge CMYK-white-backgroundEarth Science Week Geological Time




We’re delighted to announce the winners of our photography competition, ‘100 Great Geosites.’

Based on the Society’s list of 100 geosites in the UK and Ireland, published last year, the 13 images will all feature in a 2016 calendar, available for sale soon.

The competition, open to all, asked for images featuring any of the 100 sites, which include landscapes, museums, public buildings and beaches, all of which reflect the UK and Ireland’s unique geo-heritage. Continue reading

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Competition – be on the cover of the Journal of the Geological Society!

JGS coverIf you’ve ever fancied being a cover star, our flagship journal is currently running a competition for images to feature on its cover! Continue reading

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