Excavating amber

First amber excavation in the El Soplao outcrop, Cantabria, N Spain in 2008. Credit IGME-UB.

By Dr Ricardo Perez-De-La Fuente, Research Fellow

Amber, or fossilised plant resin, is a unique material to learn about the history of life on Earth. Its incredible preservation and ability to capture life “in action” are well known thanks to the Jurassic Park saga, but fewer people know where amber is found, what it looks like in the field, and how it is gathered.

Cretaceous amber, about 130 to 70 million years old, is the oldest amber that provides abundant fossils, specifically insects and spiders. Ecosystems drastically changed during this period due to global greenhouse conditions and the diversification of flowering plants, among other factors. Amber from that time has been discovered in Lebanon, Spain, France, Myanmar, eastern United States, Canada, and northern Russia.

My research team and I carry out regular amber excavations in northern Spain, working in teams of six to ten people. The outcrops that we excavate are often located next to roads and highways because amber is typically uncovered during roadworks. Excavations take place during the summer or fall to try and minimise the risk of rain, and we usually embark on one field trip each year.

The goal is to recover as much amber as possible – usually a few kilograms – from the muddy and sandy sediments. These materials were transported downstream tens of million of years ago by heavy rain and river swellings from the forests where the resin was produced, before being finally deposited in near-shore areas.

Manual extraction of amber. Credit IGME-UB
Manual extraction of amber in the El Soplao outcrop, Cantabria, northern Spain in 2008. Credit: IGME/UB.

I find amber excavations quite romantic. In the field, amber has a dull appearance that makes it difficult to distinguish from rocks or woody remains. This is due to an opaque crust resulting from oxidation in the sediments and other processes.

This outer layer makes detecting potential fossils inside the amber highly unlikely while the excavation is ongoing. So, in the field we just gather as many amber pieces as possible, and hope for the best.

Only when amber is polished – or shows broken surfaces – does its distinct yellowish to reddish shine emerge, and any possible fossils within become evident. Some ambers are highly fossiliferous, while others are very poor in fossils.

Amber can be gathered by hand using regular tools such as hammers. However, the most efficient method to extract amber from soft sediments is with concrete mixers! This rather unsophisticated piece of equipment provides the best way to recover medium quantities of amber in the field.

We charge water and amber-bearing sediments into the mixer, and after stirring for a while amber floats to the top because it is less dense than muddy water. Then, the surface of the water containing the amber is poured into sieves, which separates even the tiniest pieces.

Amber pieces recovered in a sieve after washing
Amber pieces recovered in a sieve after having been “washed” from their sediment. First amber excavation in the La Manjoya outcrop, Asturias, northern Spain in 2017.

After fieldwork, many hours will be spent looking for fossils within the amber and preparing them. Gathering raw amber is just the first part of a process in unearthing the secrets held within – fragments of encapsulated time.

Top image: First amber excavation in the El Soplao outcrop, Cantabria, N Spain in 2008. Credit: IGME/UB.

Diving into deep time

Our current First Animals exhibition is extending its run until 1 September, and to mark the extension our Research Fellow Imran Rahman takes a look at how animal life in the ancient oceans was brought to life in our Cambrian Diver interactive installation.

One of the biggest challenges in developing the First Animals exhibition lay in visualising rare fossil specimens as ‘living’ organisms, transforming them from two-dimensional imprints in the rock into three-dimensional animated computer models.

Many of the specimens on display in First Animals were collected from sites of exceptionally well-preserved fossils called Lagerstätten. These deposits preserve the remains of soft-bodied organisms that are almost never seen in the fossil record; things such as comb jellies and worms, as well as soft tissues such as eyes, gills and muscles. Even so, most of these fossils are flattened and two-dimensional, which makes it very difficult to reconstruct what they looked like in life.

Vetulicola cuneata from the Chengjiang fossil site had a large body with triangular openings on either side and a segmented tail. Its three-dimensional shape is uncertain.

To help exhibition visitors visualise the animals in a living environment we worked closely with Martin Lisec and his team at Mighty Fossils to create a set of detailed computer models of a key set of animals. We have worked with Martin before on the video of a Jurassic sea inhabited by plesiosaurs and other marine animals for our Out of the Deep display. That was very successful, but our idea for First Animals was even more ambitious: to create a unique interactive installation called the Cambrian Diver.

The material focused on the Chengjiang animals from the Cambrian of Yunnan province, China, which provides the most complete record of an early Cambrian marine community, from approximately 518 million years ago. Using fossil evidence of the organisms thought to have lived at the time we selected 12 species that were representative of the diversity of the Chengjiang biota.

The first phase was collecting as many materials as possible to be able to create 3D models. As usual, we started with rough models, where we set basic dimensions, shapes and proportions of body parts. Once approved, we moved to very detailed models for the animations, artworks and textures for less detailed models to be used within the interactive application. – Martin Lisec, Mighty Fossils

Images showing a preliminary 3-D model of the lobopodian Onychodictyon ferox in multiple views, with annotations in yellow highlighting changes suggested by Museum researchers.

To provide two-dimensional templates for Mighty Fossils to work from we scoured the scientific literature for the most recent accurate reconstructions available for each of the species.

The predatory arthropod Amplectobelua symbrachiata is a good example. We drew heavily upon a 2017 paper by Dr Peiyun Cong and colleagues, which included a very detailed reconstruction of the head region. This reconstruction shows that the underside of the head of Amplectobelua consisted of a rod-shaped plate, a mouth made up of two rows of plates, and three pairs of flaps with spiny appendages, all details that are included in our 3D model.

Scientific reconstruction (left) and our 3D model (right) of the arthropod Amplectobelua symbrachiata. Left-hand image modified from Cong et al. (2017).

Colour and texture were another consideration. To inform these we looked at living species that are thought to have similar modes of life today. For Amplectobelua, a free-swimming predator, we examined the colouration of modern marine predators such as sharks. Many sharks have countershading, with a darker upper side of the body and a lighter underside, which acts as camouflage, hiding them from potential prey.

We reconstructed our Amplectobelua model with similar countershading camouflage, with blue and red colouration inspired by the peacock mantis shrimp, a brightly coloured predatory arthropod that lives in the Indian and Pacific oceans.

3-D model of Amplectobelua in angled upper (top) and lower (bottom) views, showing countershading.

The next vital step was establishing how the animals moved and interacted with one another. This is a major challenge because in many cases there are no modern equivalents for these extinct early animals. For Amplectobelua we inferred that the flaps on the sides of the body were used for swimming, with the tail fan helping to stabilize the animal as it moved through the water. This agrees with previous interpretations of swimming in closely related animals such as Anomalocaris.

The models were built and textured by Mighty Fossils using the 3D gaming engine Unity. The video below is an accelerated sequence showing how the elements of the model are layered together.

The finished, animated and annotated Amplectobelua model is shown below, and can be zoomed and rotated. All the models generated by Mighty Fossils for the First Animals exhibition are gathered in a collection on our Sketchfab page.

Once animated models of all 12 species were created we placed them in a realistic marine environment. Study of the rocks preserving the Chengjiang fossils suggests these animals lived in a relatively shallow, well-lit sea, perhaps 50 metres deep and characterised by a flat, muddy seafloor. A continuous shower of organic particles is thought to have filled the water column, as in modern oceans.

Reconstruction of the Cambrian seafloor with ‘marine snow’

Based on present-day marine ecosystems, we infer that the number of immobile suspension feeders would have been much greater than the number of predators. As a result, we included multiple individuals of the suspension feeders Cotyledion, Saetaspongia and Xianguangia, which were tightly grouped together, but only a small number of the active predators Amplectobelua and Onychodictyon.

This scene is now populated with animals, including two predators: Amplectobelua (swimming) and Onychodictyon (centre)

The final step involved setting up a camera and user interface to allow visitors to discover the various animals in our interactive environment. For this we worked with creative digital consultancy Fish in a Bottle to identify eight locations, each focused on a different animal.

As the video above shows, users can navigate between locations by touching an icon on the screen, and when the Cambrian Diver sub arrives at a location information about the animal, its mode of life and its closest living relatives is presented on-screen. A physical joystick allows users a 360-degree rotation to look around the scene, and explore the ancient watery world.

This project was significantly bigger than the Out of the Deep work we had done previously with the Museum, mainly because of the complicated approval procedure needed for 20 individual 3D models. Along with three large illustrations, two animations and the interactive application this was a big workload! Fortunately, we managed to finish the whole project on time for the opening of the exhibition. – Martin Lisec

First Impressions: exploring early life through printmaking

Dickinsonia by Claire Drinkwater

by Rachel Parle, public enagement manager

In each of our special exhibitions, we complement contemporary scientific research with contemporary art. In recent years this has included Elin Thomas’s crocheted petri dishes, Ian Kirkpatrick’s migration and genetics-themed installation, and who could forget the enormous E. coli sculpture by Luke Jerram?!

First Animals exhibition is on show until 24 February 2020

For our current exhibition, First Animals, we’ve taken this collaboration to a new level by commissioning original works from a total of 22 artists, all part of Oxford Printmakers Co-operative (OPC) – a group of over a hundred printmakers which has been running for more than 40 years.

First Animals looks at the very earliest evidence of life on Earth, dating back half a billion years. Some of the fossils on display are shallow impressions in the rock – the only direct evidence we have that life existed at that time.

Amplectobelua symbrachiata – one of the incredible Cambrian fossils from the Chengjiang site in China

To kick-start the project we ran a series of workshops for OPC artists to meet the Museum researchers working on the exhibition, and to see the fossils first hand. There were also opportunities to draw directly from these unique fossils, many of which have never been displayed in the UK before.

Discussions between researchers and artists revealed fascinating similarities between these ancient fossils and the process of printmaking. Sally Levell, of Oxford Printmakers Co-operative, explains:

I was completely fascinated by the fossil collection in the Museum, especially the fine specimens from Chengjiang and Newfoundland. They are preserved as mere impressions in the rock, so they are, in essence, nature’s prints.

Each printmaker partnered with a researcher who could answer questions, provide extra info and help the artist decide which specimen or subject to depict in their final print. It’s clear from talking to the printmakers that this direct contact with the experts was invaluable and made the work really meaningful.

Xianguangia by Charlie Davies

We couldn’t have worked without the patient explanations and “show and tell” sessions with the three main researchers – Dr Jack Matthews, Dr Imran Rahman and Dr Duncan Murdock. They were just excellent and their dedication to their work was an inspiration to all of us printmakers.

Sally Levell

Over a period of around seven months, ideas blossomed and printing presses were put into action, with the printmakers exploring the forms, textures and evolution of the fascinating first animals. The final result is First Impressions, an enticing art trail of twenty-five prints dotted around the Museum, both within the First Animals exhibition gallery and nestled within the permanent displays.

Ottoia by Jackie Conway

Such a large group of artists brings a huge variety of techniques and styles, all under the umbrella of printmaking; from a bright, bold screen print in the style of Andy Warhol, to a delicate collagraph created from decayed cabbage leaves! To take part in the art trail yourself, simply grab a trail map when you’re next in the Museum.

Workshop printers inking up their plates

But our foray into fossils and printmaking didn’t stop there. OPC member Rahima Kenner ran a one-day workshop at the Museum where participants made their own intaglio prints inspired by the First Animals fossils. The group of eight people featured artists and scientists alike, all keen to capture the unique fossils through print techniques.

Designs were scratched onto acrylic plates and inked up, before a professional printing press created striking pieces to take home. Participants also explored techniques such as Chine-Collé, the addition of small pieces of paper to create texture and colour underneath the print.

It was a delight to be able to share with the group our enthusiasm for these discoveries in the medium of making the drypoint prints and to share their enjoyment of learning and using the new techniques. Some lovely work was produced in a single day.

Rahima Kenner

A plate about to go into the press
A finished print, using intaglio and chine-colle

The First Impressions project has been transformative for the Museum team and for the Oxford Printmakers Co-operative. Catriona Brodribb describes its impact on the printmakers :

It’s been a great opportunity to challenge one’s own artistic boundaries in terms of stretching the imagination, and for our members to throw themselves into something new, and enjoy responding to such ancient material in a contemporary way.

The First Animals and First Impressions exhibitions are open until 24 February 2020 and are free to visit.

Abigail Harris - artwork showing reconstruction of Cambrian ocean animal life

Cambrian creation

Abigail Harris - artwork showing reconstruction of Cambrian ocean animal life

by Abigail Harris

Over the past few months our researchers have been working with University of Plymouth illustration student Abigail Harris, who has delved into the weird and wonderful world of some of the earliest animals. Here, Abigail tells us about the process that led to the creation of her Cambrian artwork, inspired by our First Animals exhibition.

I first visited the Museum in April this year when I was given the opportunity to collaborate with scientists as part of a module in my BA in at the University of Plymouth. Things kicked off with a short talk about the Ediacaran and Cambrian geological periods, when Earth’s first animal life started to appear.

I quickly narrowed my interest down to fossils from the Cambrian period which are more complex life forms, more similar to life today. A collection of small fossils from the Chengjiang fossil site in Yunnan province, China was the inspiration for some initial observational drawings.

Abigail Harris - sketches for artwork showing reconstruction of Cambrian ocean animal life
A sketchbook page showing initial sketches and observations of Onychodictyon
Final illustration of Cotyledion

After returning to Plymouth University, I began to develop these initial sketches and observations, continuing to research the Chengjiang material and learning more about the characteristics of some of the creatures preserved as fossils.

I wanted to create an under-the-sea ecology reconstruction showing a diversity of life forms, focusing on Onychodictyon, Cotyledion, Cricocosmia, Luolishania, and Paradiagoniella.

A five-step process was used for each reconstruction. Initially, I would sketch the fossil as I saw it, then I would research the characteristics and features of that animal, making a list of things to include in my drawing. A second drawing would then include all of these characteristics, not just what was initially visible in the fossil.

These rough sketches were then sent to the scientists for feedback, helping me to redraw and paint the illustrations with watercolour, before scanning and digitally editing each painting. Lastly, I created a background and added my illustrations.

Initial under under the sea ecology reconstruction.

Although the reconstructions were not completely finished by the time of my project deadline, I returned to the Museum in July and was given a tour of the First Animals exhibition by Deputy Head of Research Imran Rahman, as well as the opportunity to discuss how to improve my artworks for accuracy.

Another round of sketching and painting led to the final piece, shown at the start of this article, complete with an added digital background of the seafloor, and darkened to reflect the murky world of a Cambrian ocean, 50 metres below the surface.

Exceptional Chinese fossils come to Oxford in new partnership

by Imran Rahman, Deputy Head of Research

China is world-famous for its unique and exceptionally preserved fossils, which range from some of the oldest animals on Earth, to spectacular feathered dinosaurs. We are therefore very excited to announce that the Museum, along with other institutions from across Europe, is a partner in a major new venture with Yunnan University in China: the International Joint Laboratory for Palaeobiology and Palaeoenvironment.

Collaboration between this Museum and Yunnan University dates back to the 1990s, driven by the work of Professor Derek Siveter – a former Senior Research Fellow and current Honorary Research Associate at the Museum. He collaborated with Professor Hou Xianguang, director of the International Joint Laboratory for Palaeobiology and Palaeoenvironment, to study fossils from the internationally renowned Chengjiang biota, which was discovered by Hou Xianguang in 1984.

Museum researchers Duncan Murdock, Jack Matthews and Derek Siveter (l-r) visit the Precambrian-Cambrian Section

The Chengjiang fossil site is important and exciting because it preserves both the soft and hard parts of a range of early animals. This fossil record captures the rapid diversification of life about 520 million years old – in an event referred to as the Cambrian explosion. Derek Siveter was instrumental in a successful bid to have the Chengjiang biota designated a UNESCO World Heritage site in 2012, preserving it for future generations.

In December 2018, Museum researchers Duncan Murdock, Imran Rahman and Jack Matthews travelled with Derek to Kunming, China, for the first meeting of the International Joint Laboratory for Palaeobiology and Palaeoenvironment. The lucky researchers spent three days on field trips to the region’s most spectacular fossil sites, including Lufeng World Dinosaur Valley and the Chengjiang biota itself, followed by two full days of scientific talks and discussions.

The International Joint Laboratory is funded by the Ministry for Education of China and includes the University of Leicester, the Natural History Museum, London, the University of Munich, and the Bavarian State Collection of Zoology, along with Oxford University Museum of Natural History and Yunnan University.

The arthropod Haikoucaris ercaiensis. Sometimes referred to as a ‘short-great-appendage’ arthropod, Haikoucaris had a pair of prominent grasping appendages adjacent to the head (right-hand side of this image). Credit: Scott Billings
The arthropod Leanchoilia illecebrosa. Sometimes referred to as a ‘short-great-appendage’ arthropod, Leanchoilia illecebrosa had a pair of prominent grasping appendages adjacent to the head (right-hand side of this image). Credit: Scott Billings

A significant first outcome of this new partnership will be the loan of iconic Chengjiang fossil specimens from Kunming to Oxford for our First Animals exhibition which opens on 12 July and runs until February 2020. Most of these fossils have never been outside of China before, and some have never been seen by the public before. We invite you to visit First Animals to see these exceptional fossils first hand!

The arthropod Saperion glumaceum. Saperion had a flattened, segmented body and jointed appendages (not visible in this specimen). Credit: Scott Billings.
The arthropod Saperion glumaceum. Saperion had a flattened, segmented body and jointed appendages (not visible in this specimen). Credit: Scott Billings.

Top image: The comb jelly Galeactena hemispherica. Unlike modern comb jellies, which are soft-bodied animals, Galeactena and its relatives had hardened ‘spokes’ on the sides of the body (appearing as dark bands in this photograph). Credit: Scott Billings.

Animating the extinct

This sumptuous video features on our brand new Out of the Deep display and brings to life the two large marine reptile skeletons seen in the cases. The Museum exhibition team worked with Martin Lisec of Mighty Fossils, who specialise in palaeo reconstructions. Martin and his animators also created a longer video explaining how the long-necked plesiosaur became fossilised, as well as beautiful illustrations of life in the Jurassic seas. 
Martin explains the process of animating these long-extinct creatures:

The first step was to make 3D models of all the animals that would appear in the films or illustrations. After discussion with the Museum team, it was clear that we would need two plesiosaurs (one short-necked, known as a pliosaur, one long-necked), ammonites, belemnites and other Jurassic sea life. Now we were able to define the scale of detail, size and texture quality of the model.

In consultation with Dr. Hilary Ketchum, the palaeontologist on the project, we gathered important data, including a detailed description of the discovered skeletons, photographs, 3D scans, and a few sketches.

This slideshow requires JavaScript.

We created the first version of the model to determine proportions and a body shape. After several discussions with Hilary, some improvements were made and the ‘primal model’ of the long-necked plesiosaur was ready for the final touches – adding details, mapping, and textures. We could then move on to create the other 3D models.

This slideshow requires JavaScript.

The longer animation was the most time-consuming. We prepared the short storyboard, which was then partly changed during the works, but that is a common part of a creative job. For example, when it was agreed during the process that the video would contain description texts, it affected the speed and length of the whole animation – obviously, it has to be slower so that people are able to watch and read all important information properly.

A certain problem appeared when creating the short, looped animation. The first picture had to precisely follow the last one – quite a difficult goal to reach in case of underwater scenery. Hopefully no-one can spot the join!

This slideshow requires JavaScript.

At this moment we had a rough animation to be finalised. We had to make colour corrections, add effects and sound – everything had to fit perfectly. After the first version, there were a few more with slight adjustments of animation, cut and text corrections. The final version of both animations was ready and then rendered in different quality and resolution for use in the display and online.

The last part of the project was creating a large illustration, 12,000 x 3,000 pixels, which would be used as a background for a large display panel. Text, diagrams and a screen showing the animations would be placed on this background, making the composition a little tricky. We agreed that the base of the illustration would be just the background. The underwater scene and creatures were placed in separate layers so that it would be easy to adjust them – move them, change their size, position etc.

This slideshow requires JavaScript.

In the first phase, we had to set the colour scale to achieve the proper look of the warm and shallow sea, then we made rough sketches of the scene including seabed and positions of individual creatures. We had to make continuous adjustments as the display design developed.

Then we finished the seabed with vegetation, gryphaea shells and plankton floating in the water. The final touch was to use lighting to create an illusion of depth for the Jurassic creatures to explore.

*

More Out of the Deep videos are available on the Museum website.