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Feltarbeid på Digermulen sommer 2017

Små kunstverk og Silicon Valley

Av Linn Novis.

Så var vi her, store og små.

I år, 8 paleontologer og 2 små rekrutter og en i pappaperm. Den minste (14 mnd) får fossiler bokstavelig talt inn med morsmelka.

Mens de 8 store går innover fjellet hver dag og leter etter fossiler så finner de minste spennende steiner og lager små kunstverk på stranda.

Fantasy Apidellas made by the kids.
Embla And Hulda explore the Cambrian rocks.

Vi finner mange fantastiske fossile spor etter trilobitter her på Digermulen. Disse sporene gir oss et unikt glimt av dyrets liv «en dag» i tidlig kambrium. De fineste fossilene fyller vi sekkene med og tar  med tilbake til Tromsø Museum. Men noen av disse fossile sporene sitter så godt fast i fjellveggen (typisk at disse også er de største og flotteste) at eneste måte å få de løs er flere dagers arbeid med brekkjern, hammer og rå paleontologisk muskelkraft.  Og selv om vi skulle få blokken løs er det en annen historie å frakte den ned fra fjellhyllen nesten i toppen av den navnløse store dalen som fører ned til campen vår.  Så da må andre teknikker til.

Silikon er et meget anvendelig materiale. Pensler man silikon på stein, legger den seg i alle kriker og kroker.  Når dette størkner kan en dra det av steinen. Dette gjør at vi får et perfekt avtrykk av alle de spennende detaljene vi forskere trenger for å kunne forstå sporet dyret lagde.

Og ikke minst, vi klarer å bære med oss avtrykket ned den lange veien tilbake til campen.

Da denne dalen huser de de flotteste spor og fossiler her på Digermulen, studert av nyskjerrige forsker og avbildet i en rekke magasiner, synes vi det er på sin plass å omdøpe dalen til Silicon Valley.

Jan Ove Ebbestad prepares himself for a dirty job.

 

Linn applying the silicon on the fossil trilobite traces.

 

Carry the mould down the silicon valley

Fieldwork on Digermulen, summer of 2017

Silicone Valley and works of art

By Linn Novis.

Here we are again, grown ups and kids alike.

This year, eight palaeontologists, two recruits and one grown up on paternal leave. The youngest (14 months) is basically being fed fossils together with mother´s milk.

While the eight palaeontologists hike up the valleys every day searching and mapping fossils, the youngest find their treasures and produce works of art on the beach.

On Digermulen we find an amazing array of trace fossils produced by trilobites and organisms, giving us a unique window into animal life in the early Cambrian. The best examples we will stuff down into our backpacks and bring back to Tromsø University Museum. But, some of these traces are nearly impossible to bring back (typically the largest and best ones); the only way to break them from the rock is through days of had work with hammers, crowbars and raw palaeontological muscle power. Even then, when the traces are loose, transporting them down from the top of the valley to our camp by the beach is no simple feat. That´s when other techniques come in handy.

Silicone rubber is a most useful material used in palaeontological fieldwork, spreading it thinly on a rock surface produces a perfect copy of all the cracks and fossils visible. After setting, it can be

pulled off the rock in a thin layer, almost like a rock hide. This give us a perfect mould of the surface and allows us to study and understand the trace fossils made by the animals. And last but not least, a cast is substantially easier to carry down the valley. This valley is home to some of the finest fossils found from the early Cambrian, eagerly studied by us and published in magazines and journals, perhaps it should be called «Silicone Valley».

Tallinn, Trilobites and Talks

by Jan Ove R. Ebbestad & Magne Høyberget

This time the DELGR went east, to the lovely medieval town of Tallinn in Estonia and the 6th International Conference on Trilobites and their Relatives. The meeting took place in the Gustav Adolf Gymnasium established 1631, known for being where Estonian palaeontologists of fame such as Armin Öpik, Valdar Jaanusson and Harry Mutvei graduated. Our host was Helje Pärnäste who had ardently worked to bring together nearly 80 specialists and trilobite aficionados from 15 or so countries.

A view across the old town of Tallinn from the medieval tower Kiek in de Kök.
The conference was held in the Gustav Adolf Gymnasium.

The full conference programme stretched over nearly two weeks, with pre- and post-conferences, two days of technical sessions on Saturday July 8th and Monday July 10th, and a mid-conference one-day excursion on the Sunday in between. Accompanying persons had their own full programme during the weekend.

Magne and I arrived on Friday before the meeting and joined in on the registration and ice breaker in the evening. A range of Estonian beer was available and a lovely buffet was laid out for us. The warm summer evening was perfect and catching up with old friends and seeing new faces was great fun.

 

Mingle at the ice breaker. Helje Pärnäste, the organizer of the conference, and David Bruton in the foreground. Just behind them is Frank Nikolaisen talking with Richard Fortey and Shanchi Peng.

The first International trilobite conference was held in Oslo 1973 and organized by Professor emeritus David L. Bruton and is now held every 5th year. David was, by the way, the supervisor of Jan Ove during his master thesis in Oslo. A few of the original participants of the 1973 meeting were even present during this meeting!

Helje with the dean of the Academy of Sciences (sitting) and the herald of Tallinn (re-enactment) just before the opening of the meeting

It was especially nice to meet Frank Nikolaisen who went with Gunnar Henningsmoen from the museum in Oslo to Digermulen in 1960 and 1963 to collect the first lower Cambrian trilobites. Frank told very colourful anecdotes of the strenuous travel with bus from Oslo during the first trip, a bus strike during the second trip which meant he had to hitch-hike! He got as far as Narvik before he decided to wait for Henningsmoen and his wife Kari who had travelled from Oslo with their car, a Volvo filled with the field gear. Apparently, Bardufoss was the place where they stocked up on food and beverage. Coming to Digermulen by boat meant that a fisherman dropped them of and a pick-up time was decided. The fisherman got a small bottle of booze when they parted ways with a hint that more was coming when they were picked up. This to ensure that they actually were picked up! Times they are changing…

Nikolaisen and Henningsmoen had only a week each time on the east-side of the peninsula, and it was the middle and upper Cambrian olenids that attracted Henningsmoen. This sort of explains why they didn’t find so many holmiid trilobites during their expedition.

The first technical sessions of the conference on Saturday covered trilobite lagerstätten, functional morphology, early evolution of arthropods and a poster session with a total o 23 presentations. Inbetween each session were treated to coffee, tea and croissants and lively talks and discussions. As always in these gatherings you have a wonderful opportunity to meet, talk and cover so many aspects of your work and ongoing projects.

Magne has just eyed through the diverse programme before the session starts.

Sunday was time for the mid-conference excursion, which neither of us participated in, but in the evening everyone were treated to a guided tour of Tallinn Town Hall, followed by an extraordinary medieval feast in the Olde Hansa guest house with plenty of food, drinks and entertainment in the form of live medieval music and a staff that went into their medieval roles all the way!

Frank and Magne during the Medieval feast.

Our presentation was to be given in the second session on Monday. An early start gave us first a poster session, followed by a very stimulating session on the recent developments on the Treatise and trilobite phylogeny. Of particular interest to us was a talk by Anna Żylińska and Jakub Nowicki on retro deformation of tectonically deformed trilobites. Although our material in general is relatively undisturbed, it will come in handy. The session on Cambrian trilobites followed this, and was chaired by Jan Ove and Per Ahlberg. Our presentation was the last of the session, just before lunch, but although people were now fatigued and hungry we had a few questions from interested colleagues.

After lunch the sessions proceeded in stratigraphical order, ending up with Devonian trilobites. Some 30 presentations were given this day. And suddenly the meeting and talks was over, ending with information on the next meeting which is likely to be in Cincinnati 2022 and the possible publication of results from the meeting in an upcoming Fossils & Strata. Dead line is in September already so we may be hard pressed to contribute to this volume.

To sum up, Magne and Jan Ove had a very stimulating and fun meeting in an excellently organized and lovely setting. Before the meeting we had been busy with photographing and measuring specimens, so for the first time we could present actual results from our study of the holmiids from the trilobite scree.

Jan Ove and Magne

 

Trilobite Galore in Berlin

By Jan Ove R. Ebbestad

Berlin – a City, a world Metropolis, an iconographic image – and the site of the 3rd German trilobite meeting.

Conference Proceedings
Conference Proceedings

For two intense days, I participated in this event as an invited speaker. The meeting gathered more than 100 collectors and a few professionals in a happy and successful blend, celebrating all things trilobitic. Most of the participants were private collectors, specialized on finding trilobites in erratic boulders – Geschiebe. Dr Richard Fortey, an emeritus from the British Museum of Natural history was the main invited speaker. He elegantly put it that, the only distinction between an amateur and a professional [trilobite worker] was that the professional was paid. Since he now was retired and unpaid, he therefore was an amateur!

The lecture hall is filling up.
The lecture hall is filling up.

The meeting was held at the Museum fur Naturkunde, and splendidly organized by Michael Zwanzig from Berlin, whom I have had the good fortune of meeting during his frequent visits to Uppsala. The hospitality and enthusiasm was palatable and the coffee breaks were put to good use with many discussions and reflections on specimens and collections. The level of competence and devotion to their fossils among the collectors is impressive and the opportunity to meet and discuss is therefore invaluable. My sincere thanks to Michael for the effort in bringing us all together, paid and unpaid professionals and alike.

Coffee and Discussions.
Coffee and Discussions.

This time I presented our work on the Digermulen olenelloid trilobites in a broad sense and gave the first glimpses of results from the collecting effort this season. It gave me the opportunity to discuss problems of stratigraphy and taxonomy with both Helje Pärneste from the Technical University in Tallinn and Jens Koppka, currently in Switzerland, but an avid researcher of the lower Cambrian Holmia shales of the classical Mjøsa area in Norway.

Meeting with a giant.
Meeting with a giant.

And last, but not least for my own part. I got to see the skeleton of Brachiosaurus/Giraffatitan in the Humboldt Museum.

One field day in a paleontologist’s career

By ōu zhì jí

A typical day on Digermulen starts with a cheerful breakfast in our kitchen tent — bacon, fried eggs, porridge and müsli, usually accompanied by tea, coffee or hot chocolate depending on what we feel like. Such high-calorie food guarantees enough energy for a sturdy hike in the morning and a long workday. After breakfast, researchers will discuss the day’s destinations; bad weather can have a large impact on planned work. We then grab something for our individual packs as lunch — including bread, dry tech, cup noodles, fruits, norwegian sausages, hot water and any leftovers from breakfast. We do this because the field localities are not always near our campsite, we do not want to spend lots of time hiking back for lunch.

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Figure 1. Organisms living on Digermulen besides visiting paleontologists. A: a stranded comb jelly awaiting photography. B: a lonely reindeer await his true love. C: a vivid sea urchin. D: edible mushrooms picked by Wendy.

Besides the basic necessaries for surviving a day in the field, we also need to pack our ‘working tools’. A geologist’s hammer is the most important tool, which is used in several ways, such as obtaining a fresh surface of a rock to determine its composition or reveal fossils inside, splitting fine-grained clastic rocks to search for macrofossils, breaking rocks to make them smaller for transport back to campsite, they can also be used as a scale for photography. Chisels, crowbars and sledgehammers are useful aids to the hammer. We use a high-resolution geological map, topographic maps and GPS when we get confused about the layers of rock, when we try to find an easy path to our destination, or simply record where we are in the notebook. Any interesting observations or ideas during fieldwork is written down in the notebook and we go through our notes every evening in camp. A good camera is a powerful tool to rescue paleontologists from field sketching as they did 50 years ago, especially for those who are not good at drawing. Photographing is faster and record more details than the old fashion, however, the simple sketches in your notebook are invaluable. Sampling bags and newspapers are used for packing samples. Sometimes we bring the equipment needed for casting as well — not all of the valuable specimens are possible to collect, and some are simply best left in place.

Then we head out on foot rather than four-wheelers — the only roads are reindeer trails. However, we travel by boat occasionally when the sections are all along the seashore. In the field, we observe rocks, write down what interests us scientifically and collect, or make casts of what we cannot bring back. There is a short break at noon for lunch. Moreover, we can have numerous breaks for watching whales, seals, reindeer, birds or just scenery — as long as there are no other paleontologists around!

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Figure 2. Splendid scenery on the Digermulen Peninsula. A: a quartzite castle of the Great Digermulen Empire. B: a reindeer trail leads you to heaven. C: multicolored beach made by colorful sandstones. D: a sunny day for fossil hunting. E: view over to the Varanger side. F: trilobite hunting ground.

The end of the day is to share a long dinner in the kitchen tent together. Different from the lunch, the dinner is always cooked in pots and pans (many thanks to the chefs). But, refilling empty stomachs is not the only theme: researchers take out exciting fossils collected on that day and have heated discussions. After that, a summary of the day gone by and a simple plan for the next day are discussed.

Around 10-11pm, everyone goes into his or her own tent to recover from the day’s hard work and look forward to the next expedition on the coming day. Nevertheless, I think the best way of relaxing is to loose myself in the most beautiful scenery ever to exist on our lovely planet.

1000 thanks to the organizer and everyone in the field this summer!

Scientific super powers!

By Wendy L.Taylor

All scientists use one tool more than any other in their academic arsenal – the power of observation. A keen sense of observation is the foundation of rigorous science and the key to unlocking new discoveries. In the world of field-based research, what we observe – often in the most physically challenging and uncomfortable of settings – fuels our curiosity and inspires our most basic urge to explore the world. Ionian philosophers, Anaximander and Xenophanes, of ancient Greece made some of the earliest geological observations during the 6th Century B.C.E. They noticed the presence of fossil fish and shells in rock far removed from oceans of the day and suggested they were once living animals buried in mud during ancient floods. Observations like these, paved the way for the birth of paleontology, the study of the history of life. As a modern day paleontologist, I have access to an array of powerful technologies designed to enhance and sharpen my powers of observation in the field and lab. Some new and some not-so-new tools including photogrammetry and panoramic photography, X-ray imaging and even robotic technologies make it possible to capture important scientific details and share discoveries with the public in new and exciting ways. Here are some examples from our recent expedition to study the extraordinary fossils of the Digermulen Peninsula in northern Finnmark.


Figure 1: Flying of “Major Tom” (inset) in the field at Digermulen (left). A drone’s view of the Lower to Middle Cambrian age rocks (~540-520 million years) of Breidvika Valley.

First used on a large scale by the military for combat purposes, growth in the use of UAV’s (unmanned aerial vehicles) or drones has dramatically expanded over the past 10 years due to the miniaturization of scientific instrumentation and the accessibility of affordable models. Today there is widespread deployment of drones in the biological, geological and atmospheric sciences. Images and video taken by our project’s drone, affectionately named “Major Tom”, at Digermulen give a bird’s-eye view of important rock outcrops (Fig. 1) that record approximately 200 million years of Earth history during a critical time in evolution of complex life. These rocks contain the oldest evidence of multicellular animal life in Scandinavia!

Another tool we use to image rock surfaces in the field is panoramic photography. This technique is done with a camera mounted on a specialized panoramic tripod head that allows 360° rotation on a tripod (Fig. 2). A series of images are taken at 30° increments and stitched together using specialized software.

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Figure 2: Spherical panorama set up (right) and me photographing at Digermulen (left). 360° panorama movie made of one study site at Manndrapselva.

The resultant 360° interactive movies or “sphericals” can be hosted on websites and offer an immersive view of remote field sites (Fig. 2). Examples of spherical panoramas used for geoscience education can be found online at http://vft.asu.edu. We also capture high-resolution gigapixel panoramas that are made of 100’s to over 1000 images stitched together. These images give researchers the chance to study the details of large areas that are difficult to access in the field and can also be used in a variety of educational contexts.

For the study of much smaller features such as the delicate morphology (form and structure) of fossils and their state of preservation in the rock (or taphonomy), we use macro photography (see Fig. 3). This type of photography is done using a camera with a macro or close-up lens mounted on a tripod (or copystand) with lights. Many fossils require extra preparation before they can be photographed. The first step involves the cleaning and removal of any extra rock covering the fossil (mechanical preparation), 2) blackening with water-based ink to reduce the effect of colors on the surface, and then 3) whitening with ammonium chloride to bring out fine details. Whitening is done with a glass tube filled with ammonium chloride powder that is heated over a flame (Fig. 2). When heated the powder forms a gas that sublimates when it cools to form a white coating on the rock. This enhances fine surface details and often brings out features the eye cannot discern. Now the fossil is ready to be photographed.

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Figure 3: Fossil specimen being blackened with ink (left), whitened with ammonium chloride in a fume hood (bottom) and then photographed.

These modern tools enhance our limited human capabilities allowing us to make many more observations much more precisely. We need all the help we can get to extract the elusive clues of how organisms lived and died in ancient oceans over 540 million years ago!

Tracing the early evolution of animals on Digermulen Peninsula

by Sören Jensen

For most of the Earth’s history life consisted of small, mainly single-celled, organisms. It is only in rocks deposited during the last 570 million years before the present that large, complex, fossils appear, indicating the rise of animals. Digermulen Peninsula, northern Norway, offers the opportunity to study rocks, the Stáhpogieddi and Breidvika formations, laid down during the time of early evolution of animals. The interpretation of the best known of the earliest large complex fossils, the so called Ediacara-type fossils, also found on the Digermulen Peninsula, is controversial; some may bear no relationship to now living animals, some may be related to cnidarians, with there being few candidates for bilaterian animals such as worms or arthropods. Some of the earliest evidence for bilaterians, in fact, comes from burrows and other activity left on, and inside, the sea-floor. Although little can be said about the producers in detail, the complexity of the traces suggest they were made by an organism with features characterizing bilaterian animals. This includes an anterior concentration of the nervous system and an internal body cavity. So, by the beginning of the Cambrian Period, some 542 million years ago, complex branching burrows are found, some of which are called Treptichnus pedum (see image). The argument can be extended to even earlier and more simple trace fossils (see image), on a global scale indicating that bilaterian animals were around at least as far back as 555 million years before the present.

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Trace fossils from the Digermulen Peninsula. To the left, Treptichnus pedum, from the basal Cambrian part of the succession; to the right, simple trace fossils from late Ediacaran rocks. Photo Sören Jensen, scale is 2 cm for both images.

After the appearance of complex branching trace fossils, the next major innovation, about 535 million years ago, was the appearance of trace fossil showing evidence for limbs such as those on modern arthropods. This order of appearance of trace fossils has been documented globally, and the first appearance of complex trace fossils such as Treptichnus pedum has been choosen to mark the beginning of the Cambrian Period of time; on the Digermulen Peninsula, placing the Ediacaran-Cambrian boundary in the upper part of the Stahpogiedde Formation. Rusophycus, a burrow made by arthropods, occurs slightly higher in the succession, in the Breidvika Formation. Ediacara-type fossils are known from lower and middle part of the Stáhpogieddi Formation. No trace fossils have been found in these beds, suggesting either an age older than about 555 Ma for these fossils, or that the activity did not get preserved. This is one of the questions that we are currently exploring.

Forsteinet oppførsel

Av Magne Høyberget

Det å finne fossiler etter urtidsdyr er selvfølgelig svært spennenede og interessant i seg selv, men vi finner også en annen slags type fossiler her på Digermulen: Vi finner noe så utrolig som forsteinet oppførsel etter disse dyrene. En lang rekke forskjellige organismer som trilobitter og andre leddyr, marklignende vesener og bløtdyr har beveget seg gjennom mudderet på en havbunn som er eldre enn en halv millard år gammel og etterlatt seg spor! Noen steder er det så tett med sporfossiler at de nærmest dekker lagflaten.

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Fig. 1: Store gravespor ligger så tett at de overlapper hverandre (Foto Magne Høyberget).

Det fantes et mylder av vesener som ikke hadde noe hardt skall og som dermed ikke kunne bli forsteinet. Takket være sporfossilene så ser vi at det har vært et slikt yrende liv på urtidshavbunnen.
De forskjellige organismene har etterlatt seg sine helt spesielle og gjenkjennelige spor. Noen gravde seg loddrett ned, andre ploget og snodde seg fram, mens atter andre gikk i spiral eller lagde seg forgrenete graveganger i mudderet. Disse sporene og gravegangene i mudderet ble siden fylt igjen med litt grovere sand. Gjennom millioner av år er både mudder og sand forsteinet. Sandinnfyllingene er motstandsdyktige mot erosjon, mens den bløtere mudderforsteiningen har løst seg opp og dermed står flotte avstøpninger igjen etter sporet. Rett og slett en forsteinet oppførsel!
Disse sporfossilene blir gitt navn etter hvordan de er blitt lagd. Dette betyr at forskjellige arter kan ha beveget seg på samme måte og dermed lagd samme type spor.

Slike sporfossiler er nyttige. Noen dyr gjorde helt karakteristiske bevegelser og flere av disse lett gjenkjennelige sporene er funnet over store deler av verden. Noen lagrekker har sine helt typiske sporfossiler, dermed kan vi sammenligne med andre steder i verden og si noe om alderen på de lagrekkene vi undersøker.
Vi har til og med lett etter helt spesielle typer spor som vi forventet å finne i bestemte lagrekker, fordi de burde opptre på samme tid på Digermulen som andre steder i verden –og funnet dem!
Vi finner også nye typer spor som viser en oppførsel som ikke er beskrevet tidligere. Disse kan vi beskrive og gi nye navn.

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Fig. 2: Her er det sannsynligvis den samme trilobitten som har gravd ned i mudderet og etterlatt seg krafsespor. Denne type krafsespor kalles Rusophychus. (Foto Magne Høyberget)

Trilobittene har etterlatt seg mange forskjellige slags spor etter forskjellig slags oppførsel. Dette kan være både hvilespor, gang- og løpespor eller spor etter jakt. Alle disse sporene har dermed fått forskjellige navn. Det kan til og med se ut som om vi finner spor etter dramaet der trilobitten har krafset seg gjennom mudderet langsetter et markspor og fanget marken. Gravesporet etter marken ender brått i trilobittens krafsespor.
Dermed forteller sporene oss noe om hvordan de forskjellige dyrene faktisk levde i kambriumperioden, for en halv milliard år siden.

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Fig. 3: Her har en trilobitt ploget seg gjennom mudderet og etterlatt seg et langt spor med avtrykk etter beinparene. Denne type spor kalles Cruziana. (Foto Magne Høyberget)

Biostratigrafisk överblick utav utbredningen av Sabellidites – en loggblogg

Av Frida Hybertsen

Att åka ut i fält inger alltid en särskild känsla av upprymdhet och speciellt nu när jag får chansen att vara en del i en riktig forskningsexpedition. Vid fossilletande i en lagerföljd är det viktigt att kunna korrelera sina fynd till en viss nivå i lagerföljden så att det är lättare att jämföra med samma lagerföljd på en annan plats. På så vis kan en överblick utav utbredningen av ett specifikt fossil ges på olika ställen och det blir lättare att återskapa t ex levnadsförhållandena som de var eller preservationen av fossilet. Min del i det här projektet är att skapa en logg över den tredje cykeln i Manndrapselva member, Finnmark i vilken utbredningen av fossilet Sabellidites är beskriven. Det kanske inte låter som en alltför svår uppgift, men att skapa en tillräckligt detaljerad logg över nya sediment som jag bara sett på karta tidigare när jag dessutom bara tränat loggning på sektioner några få meter höga och under mycket kortare tid så blir det här en ganska knepig uppgift. Som student har jag inte riktigt hunnit upprätta en vana för loggning, vilket hade gjort uppdraget mycket lättare.

När jag först fick se sektionen som skulle loggas tyckte jag att det såg bra ut, lagrena var väl exponerade och såg ut att vara lätta att följa. Jag fick hjälp med att etablera en startpunkt, min nollpunkt i loggen. Nollpunkten sattes strax under ett finkornigt lager innehållandes massiva sandstenlinser – distinkt och lätt att komma tillbaka till. Därefter började jag beskriva lagrena.

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Figur 1: Lagerföljden mellan 0-6 m i loggen. Foto: Bianca Harrison.

Manndrapselva mbr är ca 60 meter tjock och lagrena har beskrivits tidigare, men inte just här. Jag fick därför rådet att logga en meter i taget för att få tillräckligt många detaljer i loggen. Efter att ha loggat ca tre meter på en halvtimme insåg jag att min logg förmodligen är alldeles för detaljerad. Ett nybörjarmisstag. Då jag tog ett steg tillbaka och tittade på hur lagerföljden såg ut ovanför och under den meter jag loggade insåg jag att lagrena var väldigt uniforma och att jag då hellre kunde logga upp till tre meter istället för en meter just här. På så vis loggar jag en yta som är i stort sett likadan i ett längre spann och kan då markera större förändringar eller speciella strukturer här som en notis vid sidan om loggen. Då blir loggen mindre plottrig och lättare att överblicka. Så istället för att stirra mig blind på varje liten centimeter kunde jag nu skissa på en mer generell logg och så fort jag hade lärt mig ungefär hur detaljerad loggen skulle bli gick det lättare och snabbare att logga resten av sektionen. För att hålla koll på var i loggen jag befann mig vid fick jag hjälp att sätta ut nivåmarkeringar så att jag lätt kunde se hur högt upp i lagerföljden jag befann mig.

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Figur 2: Nivåmarkering 25,5 m. Nästan halvvägs! Foto: Frida Hybertsen

Eftersom fokus i min uppgift ligger på att visa utbredningen av ett specifikt fossil i en lagerföljd behöver loggen inte innehålla centimetervisa detaljer, men eventuella strukturer i lagrena såsom rippelytor, strykning och stupning, erosionsytor etc. är inkluderade för att ge en så klar bild som möjligt. För att visa utbredningen av Sabellidites loggar jag provtagningplatser markerade av mina projektkollegor. Där någon av dem hittat ett fossil placerade de ett gult band så att jag senare kunde gå och samla in samt numrera alla prover. Numreringarna fördes sedan in i loggen som en notis vid den nivå som fyndet gjorts.
Jag loggade hela sektionen under två dagar, den första skissen var nästan färdig under dag ett. Det gick extra fort eftersom jag hela tiden hade hjälp utav en annan masterstudent, Bianca. Under dag två var jag tillbaka i sektionen för att färdigställa loggen. Då fick jag även input från flera håll angående eventuella ändringar och generell feedback, mycket uppskattat!

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Figur 3: Förslag till ändringar och generell feedback innan loggningen under dag två. Foto: Wendy L. Taylor.

Men efter det ville jag helst göra om hela loggen eftersom jag tyckte att den hade för många brister. Efter lite eftertanke insåg jag dock att alla detaljer faktiskt finns i mina anteckningar, om än lite ostrukturerat. Jag får kanske rita om loggen både en och två gånger, men all information är samlad och mitt fältuppdrag är avklarat.

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.

Fig 1
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).

Fig 2
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.

Fig 3
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).

Fig 4
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).

Figure1
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.

Figure2
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.

Figure3
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.