Birka Behind the Scenes

If you were to sum up an archaeologist in a single phrase the old adage ‘Jack of all trades but master of none’ seems quite appropriate. As an archaeologist you need to be part historian, part linguist –  part geologist, part chemist – part anthropologist, part sociologist, part artist – and of course in our case part diver. Operating as a successful field archaeologist calls into play an even greater variety of skills. Large scale excavations require a tremendous amount of infrastructure and Birka is no exception.

Behind the scenes we have had to wear many different hats in order to work effectively. While working at Birka this year I have found myself employed as a mechanic, engineer, and electrician, just to name a few.

Unseen to most we have a complex network of electrical cables powering our field office, computers, cameras and other electronic equipment, as well as a significant amount of electricity to power our underwater dredges used in the actual excavation. Without our large diesel generator to power the excavation and digital equipment we would likely amount to no more than a bunch of people in fancy suits splashing around in the water.

Beginning scaffold construction

The excavation platform that allows us, and the public, access to the excavation site required a crash course in underwater engineering. After our success constructing a 60m long dive platform last year we decided to up our game and create a multi level dual platform, one servicing the divers and one for the public to observe. While dodging exposed archaeological timbers on the sea bed we were successful in constructing a rigid and extremely functional platform from which to work. By no means was it a piece of cake, but with a bit of grit and muscle, and some savvy engineering we pulled it off.

Diving plattform in use

Finally, no excavation is truly complete without a bit of bad luck. The engine on our aluminum boat gave out a few days ago, right as we were poised to use take it out to investigate some underwater anomalies identified through a bathymetric scan of the lake. However, a new part was ordered and within a day we had it back up and running. I’ve never taken apart or re-built an outboard engine, so the process was a bit of trial and error, but I have no doubt the experience will be helpful in the future.

There is so much more than just diving and excavation that goes into making Birka a productive project. Everyone on the team brings different skills to the table, which are essential to our success. No matter what the task we have someone ready to meet the challenge, whether by experience or trial by fire.

Mike Moloney

"-Initiering har tappats"

This year I once again met my very close but somewhat annoying friend; Trimble RTK (Real Time Kinematic) Positioning System. This machine offers centimeter level position accuracy…when it works.

The RTK can for example measure the position of our trench, the depth of it and the structures found in it and import that data to GIS software. In GIS we can play lot with it and get nice visualization of research area.

Bild: 3D view of trench (orange line), rocks (grey blocks), topographic line (light blue) and water level (blue)

Last year Trimble RTK really didn’t work but this year it has worked ok…..more or less.

Bild: Diver taking measures of timbers

Since we work in an underwater environment at Birka it gives RTK some challenges. It works fine when we are high enough from the water surface but when getting closer to the water it tends to drop out and lose itself from the face of the earth. RTK has informed me quite often the last days, with a bit irritating computer voice: -Initiering har tappats, Initiering är klar ... -Initiering har tappats, -Initiering är klar. After several re-boots it has though found its way back. And of course, when the team is good all challenges can be won. As Mika Häkkinen would say, the Race was good but the road was slippery AND I would like to thank the team.

Maija Huttunen, Pintafilmi, Finland

 

Bild: Archaeologist taking measures of lakebed

Ett bryne med norskt ursprung?

To dager har jeg tilbragt nå på Birka, og det har på ingen måte värt skuffende for en norsk marinarkeolog på besök. Under vann varierer forholdene fra meditativ zen-graving med sikt opptil en meter (drömmeforhold!) til lett forvirring der man knapt vet opp eller ned, hvilket lag man graver, eller overhodet hvilken rute man faktisk er i. Men så ligger man der da og tenker at nå får man jammen bare ta seg sammen, og så med ett letter sedimenttåken et öyeblikk og der ligger det en brynestein av aller, aller fineste kvalitet. Ah!

Det er klart at hjertet banker litt ekstra i slike öyeblikk. Og för man får tenkt så mye på vikingen som var så uheldig å miste praktbrynet, eller kanskje til og med kastet det i vannet av grunner vi i dag har vanskelig for å forstå logikken i, så tenker man at dette öyeblikket blir bra å ha på netthinnen i vinterhalvåret. Når man sitter på kontoret, skriver rapporter, og er langt borte fra nesten altfor varme sommerdager på Birka. Ekstra moro, eller roligt som svensker sier, var det at en hel gjeng med besökende på bryggen fikk overväre öyeblikket da brynesteinen kom til overflaten for förste gang på over 1000 år.

Brynesteiner må ha värt en gjenstand (föremål) som ingen kunne klare seg uten. Alle egger; kniver, nåler, sverd og ökser, måtte skjerpes for å kunne fungere optimalt. Et godt bryne sörget for det. Mange av brynesteinene som ble ansett for å väre best til dette, ble eksportert i store kvanta fra Telemark i Norge allerede fra vikingtiden og gjennom middelalderen. Om dagens Birka-bryne kom fra Norge tör vi ikke si for sikkert riktig enda. Men det ble ikke plantet i feltet av en nordmann i all fall!

Tori Falck, Norsk Maritimt Museum

En hink med vikingatida tjära!

Det är nu sjätte säsongen som jag är med och gräver här ute i Birkas hamn, ett arbete som aldrig blir långtråkigt. Efter alla år så har vi rätt bra koll på vad som döljer sig nere i kulturlagret och det är numera sällan som vi blir överraskade av något ovanligt fynd. Men igår så blev jag överraskad!

Jag var nere i schaktet och grävde i ruta 5 i det lager som vi kallar nr 3, cirka 20 centimeter under botten. Lagret var fullt med huggspån, träkol, pinnar och djurben, varvart med en grå siltig lera. Plötsligt ändrade botten karaktär. I ett hörn av rutan blev leran ljusblå till färgen och det började komma fram lite läderfragment. Ytterligare några centimeter ner kom fram en brunsvart fläck som var kladdig som klister. Det bruna kladdet fastnade på fingrarna och jag var tvungen att gå upp ovanför ytan för att lukta.

Det luktade som jag misstänkte. Tjära! Jag hade grävt mig rakt ner i en tjärbehållare från vikingatiden. Botten av behållaren var rund och tillverkad av björknäver och det verkar som om sidorna varit gjorda av läder som omsorgsfyllt sytts fast i den runda näverbotten. Vi misstänker att blåleran fungerat som tätning i kärlet för att tjäran inte skulle rinna ut. Otroligt spännande!       

Nu har vi bärgat behållaren och vi ser med spänning fram emot kommande analyser av innehållet!