On the opposite side of the world

by Bianca Harrison

I had the privilege of yet again joining the Digermulen Early Life Research Group, but this time in their preferred environment – the field. In the span of four days, I had travelled via aeroplane, car and boat just to arrive in their home for the next two weeks.

Working in South Africa presents its own challenges during fieldwork but I thought it would be interesting to see just how different working in Norway really is. The nature of fieldwork itself is no different – wake up, eat some food, work till you drop and repeat! However, there are some startling differences working in Norway. The biggest and the hardest thing I found adjusting to, is the midnight sun (figure 1). In essence, there is no end to fieldwork as it never gets dark. Apart from the initial challenges, 24 hour sunlight can be a HUGE advantage. There is no risk of losing your way back to camp after dark or stumbling to the toilet in the middle of the night. It also allows you to work until you are satisfied with what you’ve accomplished in one day. Often in South Africa, you race against the clock to achieve your goals.

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Figure 1. The view of the campsite at 22h00, where in my opinion, it should be completely dark. Photo: Bianca Harrison

Another significant difference is that there are almost no dangerous animals in the field as it is too far north and thus, too cold. In South Africa, we have all sorts of dangerous critters ranging from snakes and spiders to baboons. This means you have to be extra careful where you walk or pick up a rock as you never know who may be there. So far, it seems the only real hazard in Norway is yourself! The main wildlife observed in the field includes seagulls, eagles and reindeer. This is similar in regards to South Africa as we also have birds of prey and small buck – but these largely include duiker and springbok. They are much smaller than reindeer, so it is quite amazing to see the larger reindeers grazing the hills (figure 2).

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Figure 2. A herd of reindeer running through the hills (photo Bianca Harrison) compared to the smaller antelope of southern Africa (photo Wikimedia).

Field logistics are another story. In Norway, the mode of travel is generally the BMW 2 Series, i.e. your feet, and setting up and moving campsites requires a boat. This is where you may encounter the most challenging problems. Recently, we experienced rough sea conditions that made leaving the campsite impossible (figure 3). The sea was too rough and the boat too heavy to leave shore. In contrast, fieldwork is conducted with 4×4’s on farm roads in South Africa. The most common problem is getting stuck in the sand or mud and instead of waiting for the sea to calm, you have to go and find a farmer to tow you out.

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Figure 3. The Norwegian team being buffeted by waves whilst trying to leave shore compared to the dirt roads typical of fieldwork in South Africa. Photos: Bianca Harrison

The last strange concept (to me) is finding edible food in the field. The overarching control is the difference in climates but it is simply amazing to find mushrooms in the field to add to dinner or small berries to serve as snacks on long hikes (figure 4).

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Figure 4. A – A mushroom collected in the field for dinner (Photo: Bianca Harrison). B – Patch of wild blueberries (Photo: Heda Agić). C – Crushed blueberries used as a pancake filling (Photo: Heda Agić). D – Blueberries and cloudberries growing in abundance (Photo: Wendy L. Taylor).

At the end of the day there can be nothing said for being in the field – whether in Norway or South Africa. Each environment comes with its own terms and conditions but these are quickly forgotten in light of the amazing discoveries that are made.

“Missing rocks” on Digermulen Peninsula: Stratigraphic gaps in the sedimentary record

by Guido Meinhold

Digermulen Peninsula in northern Norway comprises a well-exposed succession of siliciclastic sedimentary rocks which were deposited between circa 630 and 480 Million years ago during Late Precambrian to Ordovician times. Sedimentary rocks are deposited layer by layer on top of each other (Figure 1).

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Figure 1. Cambrian sedimentary succession at Breidvika bay along the southeast coast of Digermulen Peninsula (Photo Guido Meinhold).

Under ideal conditions there would be a continuous sedimentary record of Digermulen’s geological history. But this is not the case because Digermulen’s sedimentary record is in parts incomplete due to so called “hiatal surfaces” which reflect times of non-sedimentation and/or post-depositional erosion. These stratigraphic gaps can have durations of a few weeks and months or even up to several million years depending if they are of regional or global significance. With this in mind, the geologist knows that portions of the sedimentary archive, meaning parts of the geological rock record, are missing.
Hiatal surfaces can be identified by careful studying the lithology, contact relations and stratigraphic ages between the various sedimentary beds. Good indications for the presence of a hiatal surface are as follows:
1) Abrupt changes in grain size: For example, a mudstone bed is overlain by a conglomerate bed, and the conglomerate contains reworked clasts of the underlying mudstone.
2) Abrupt changes in rock lithology and facies: For example, a limestone bed is overlain by sandstone with, for example, the limestone having been deposited in a marine environment while the sandstone was deposited in a fluvial environment on the continent.
3) Abrupt changes of the geological age of the sedimentary beds: For example, a circa 600 Million years old sedimentary rock is overlain by a circa 580 Millions years old sedimentary rock.
On Digermulen Peninsula, several hiatal surfaces can be studied. One example is related to the so called Mortensnes Formation. This unit comprises mainly silt- to sand-sized material in which up to 30 cm large angular clasts of older (reworked) rock material are embedded (Figure 2). The Mortensnes Formation is a glacially-influenced sedimentary succession deposited during a short time interval in the Late Precambrian. The base of the Mortensnes Formation is represented by a hiatal surface which was formed due to abrupt climatic changes probably circa 580 Millions years ago. A glacial event caused a drop in sea level which led to partial exposure of the land and erosion of the underlying (older) rocks by ice and melt water. The eroded material was redeposited and now forms the main components of the Mortensnes Formation. At the base of the Mortensnes Formation likely a few millions years of Digermulen’s geological rock record are missing.

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Figure 2. Glacially-influenced sediments of the Mortensnes Formation along the southeast coast of Digermulen Peninsula (Photo Guido Meinhold).

Another example for hiatal surfaces is found within the so called Manndrapselva Member of the Stáhpogieddi Formation. This unit comprises mainly mudstone, siltstone and sandstone. Occasionally, a few up to 5 cm thick conglomerate layers with well-rounded clasts of up to 1 cm in diameter are found (Figure 3). These layers indicate times of erosion, probably related to tectonic processes. The duration of these stratigraphic gaps is still unknown but they are likely of minor (regional) significance, meaning that within the Manndrapselva Member only a few months or years of Digermulen’s geological rock record are missing.

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Figure 3. Conglomerate layer within the Manndrapselva Member along the southeast coast of Digermulen Peninsula (Photo Guido Meinhold).

The formation of hiatal surfaces is often due to prominent changes in the depositional environment. This can be triggered, for example, by climatic changes (e.g., base of Mortensnes Formation) and/or tectonic processes (e.g., likely within the Manndrapselva Member). Hence, recognition of hiatal surfaces is important for better understanding Digermulen’s geological history and for estimation of the rates of abrupt climatic changes and/or tectonic processes.

Strandet i Breidvika

By Anette Högström

I går skulle vi flytte leieren, men været var ikke helt med oss. Sterk østlig vind skaper store dønninger på vår side av Tanafjord og vi kommer oss ikke fra stranda med den lille båten for å laste over til den store båten. Manndrapselva får vente til været tillater oss å flytte.

Så hva gjør geologer når de blir satt på vent av været?

Det primære er selvsagt å holde kontakt med våre fiskere og se om været forandrer seg og det da blir mulig å pakke sammen leiren.

En stor porsjon tålmodighet er å anbefale for slike dager. Magne, Zhiji og Jan Ove går i vei til trilobittlokaliteten bare for å titte en gang til og kommer hjem med den beste fangsten så langt!

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Figur 1: Trilobitt fangst! Foto Magne Høyberget.

Vi setter oss ned i kjøkkenteltet, plukker fram ukens notater og diskuterer høyt å lavt; Frida, Zhiji og Bianca jobber med sine feltnotater, retter spørsmål og oppdaterer seg. Ikke alt fungerer, Guido må gi sin dator førsthjelp da den ikke vil starte, men til Guidos store lettelse er den nå med igen.

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Figur 2: First Aid for en dator som ikke helt vil vare med. Foto Jan Ove R. Ebbestad.

Wendy tar sjansen til ett par ekstra stunder for å fiske og det blir sei til kveldsmat.

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Figur 3: Sei fiske til kvelden. Foto Jan Ove R. Ebbestad.

Got to catch them all!

by Jan Ove R. Ebbestad

During the hectic field days loads of fossils and sediment samples are collected. These make their way to the Tromsø Museum collection and are an absolutely essential part of the scientific documentation of the studies that we do, together with photographs, measurements and field notes. The Museum collection also becomes a permanent scientific archive that is available for researchers all over the world, so they don’t have to go to the field and try to find similar specimens. It is first of all very expensive and the Digermulen Peninsula is pretty remote. In addition fossils and samples do not just pop up but requires careful and diligent collecting. So therefore we try to bring back as many of the specimens we consider valuable for our studies.

But we can’t catch them all!

Sometimes a fossil cannot be extracted from the rock it is in simply because it is to tricky and any attempts to collect them may end up destroying them instead. Or the fossils may be too large to haul back. We do not have access to any help and have to rely on our own blood, sweat and tears to get the samples out. So what can we do to document them? Photographs or drawings help, but the next best to the real thing is a cast.

This year we therefore brought with us silicon rubber to cast specimens. We had previously selected a few prize specimens to cast and knew therefore approximately how much equipment and casting supplies we needed.

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Figure 1. A large and very instructive trace fossils called Dimorphichnus that we decided to cast (photo Magne Høyberget).

We had a box with the stuff, including the silicon, the catalyst to make it cure, thickener to make it sticky, black powdered colour, a couple of containers to mix it in, a scale to get the proportions of silicon and catalyst right, protective gloves and aprons, paper tissue to clean, brushes to apply the ready mix, cloth to strengthen the silicon and plaster strips to make a casing (mother mould). The colour is added to the silicon to create a dark surface for contrast when we later will photograph the silicon casts.
The casting process is pretty straight forward, but requires warm and dry conditions to work. After mixing the silicon mass we applied it to the fossils with a brush, making sure to work it in thoroughly so that the silicon catches all the details and we get all the air bubbles out.

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Figure 2. The casting process. A) selection of the equipment needed for casting, B) mixing the silicon. C) applying the silicon with a brush. D) applying the plaster to support the silicon (mother mould) (photos Wendy Taylor).

We applied three layers with cloth in between for added strength. We then left the silicon over night to let it cure, and the following they we prepared the mother mould with the plaster strips. These were simply dipped in water and applied to the silicon in several layers and left over night to dry and harden.
The end result is a cast of the fossil, but the ‘negative’ if you like. Back in the lab we can reproduce the fossil as it looked in the field by preparing a plaster cast from the silicon mould.

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Figure 3. Sören with the finished silicon mould and plaster casing (photo Magne Høyberget).

Braving bumpy seas (for science!)

By Heda Agić

Past field seasons have intrigued us about what lies “beyond the horizon”. For a more complete picture of the traces of early life preserved in Digermulen rocks, the team would have to reach areas a long way away from the traditional campsites than attempted previously. Yet it is not always possible to reach these locations on foot. Either they’re too far away (Digermulen has no roads apart from thousands-of-years-old reindeer trails), and sometimes the outcrops of interest lie on steep cliffs impossible to get down to without climbing gear. As a solution to our exploration woes, we have decided to use a small boat to hop on/off various vistas and points of interest.

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Figure 1. Team en route to check a few outcrops before getting to the first campsite at Breidvika valley. Photo Wendy L. Taylor.

The vessel is a simple fishing motorboat driven by the local fisherman Trygve (Figure 1).
While the group loaded the gear for the next couple of weeks and boarded the larger fishing boat of captain Joachim, a smaller party of three geologists/palaeontologists set out with the small boat to visit a few localities before reaching the first campsite. The initial leg of our journey was pleasant, with only light cloud coverage. We ate packed lunch on the boat, while scrutinizing the passing outcrops. The first stop was reached at 1 o’clock: the Mortensnes diamictite (Figure 2), a deposit of one of the global glaciation events in the Neoproterozoic Era (“Snowball Earth” ice house).

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Figure 2. Large rock pieces deposited in the finer grained sediment are an indicator for glacial activity. Photo Jan Ove R. Ebbestad.

The sea got wavier as we approached our stop. Trygve deemed it impossible to take the boat ashore on a pebbly beach nearby. We would have to get out straight to the ledges. Thick coverage of slimy brown algae made it easy to grab onto something while climbing onto the cliff-face, yet it also made it tricky to balance on. As we eagerly sampled, the seas became even more restless. It was time to go. However, our blue boat couldn’t come as close to the ledge as before. Ok, samples first then – they’re more important than the geologists. A swing – and the sample box hit the boat. Phew. Geologists’ turn. The boat was swaying away, threatening to leave us on the diamictite for good, while the colleague on the boat desperately tried to hold onto the slippery, treacherous algae.
There will have to be a jump. So jump I did, as the boat suddenly jerked away from the rocks, and for a moment I thought I would end up in cold Arctic waters much like Ben Stiller in his faithful jump in “The Secret Life of Walter Mitty”.

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Figure 3. Passing Arasuola island. Photo Heda Agić

Alas, I managed to land safety, albeit ungracefully. Soon, the entire party was on board, successfully avoiding a close encounter with the fjord. But not for long. The sea got choppier and the waves kept crashing inside the boat, blinding all three bespectacled geologists with salty spray. We kept clutching onto precious samples. Digermulen field season 2016 has begun with a free rollercoaster ride! A bumpy hour later, we reached dry land before the rest of the team in the bigger ship.

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Figure 4. Trygve in the small blue boat, after dropping us off on stable ground. Photo Bianca Harrison.

Fieldwork summer 2016

By Anette Högström, all photos Wendy Taylor

The Digermulen Early Life Research Group has gathered again for two weeks of fieldwork on the Digermulen Peninsula. Our group is large with seven researchers, 1 PhD student (Zhiji from Tromsø University Museum) and two MSc students; Frida from Uppsala University and Bianca from Cape Town University. Leaving the harbor in Sjursjokk we are all very excited, two precious weeks in one of the best places to investigate the earliest appearance of animal life in the world. Several of the team members have been coming here since 2011 and it feels a bit like home now.

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This year we are; Anette Högström, Jan Ove R. Ebbestad, Wendy L. Taylor, Sören Jensen, Guido Meinhold, Heda Agic, Magne Høyberget, Zhiji Ou, Bianca Harrison and Frida Hybertsen. People have come from all over the world with Bianca coming straight from South Africa. Local fishermen, Joachim and Tryggve, get all our equipment and us to our first campsite at Breidvika. The weather reports have been very promising, we´re just hoping it´s not going to be too to hot!

Setting camp is always a bit nerve racking, finding out what has been forgotten. When we can´t find the pole for our big kitchen tent panic feelings grow very quickly, luckily it´s there where it should be. Finally at night everything is done and located and the view from camp over Tanafjord and the Varanger peninsula on the opposite side is spectacular. After dinner we crawl exhausted into our tents. Tomorrow work starts and happy hunting for the next two weeks.

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