Thursday, 22 August 2013

More on field conservation at Olduvai Gorge, Tanzania

Futher to Renata's post on our field work at Olduvai, here is a bit more detail on the project and the conservation approaches we've been trying. 

Olduvai Gorge is a pretty unique place, internationally famous for Mary and Louis Leakey's discoveries of early humans, it was the first site for the discovery of the earliest stone tool culture, the Oldowan. It was also one of the first sites in Africa where the subsequent culture, the Acheulean, was discovered and is where the traditional view of the Oldowan/ Acheulean transition was established. 


View of the gorge towards HWKEE, one of OGAP's trenches, from Olduvai Museum


OGAP, The Olduvai Geochronology and Archaeology Project, brings together researchers from various disciplines from UCL, the Universities of Wisconsin, Indiana, Colorado State and Dar es Salaam as well as collaborators from the University of Erlangen-Nürnberg and University of Liverpool to interrogate the traditional model of technological change from between the Oldowan and Acheulean. You can read more about the project on its website: www.olduvai-gorge.org.


 
Camp picture - all of the teams working at Olduvai during the 2013 season. Photo: Michael Pante



















2013 was the first year UCL conservators have been involved in OGAP’s field work.
At work in the Laetoli lab in the Leakey camp. Photo: Gai Jorayev




The conservation work focused on developing new approaches to lifting and consolidating fragile fossil and lithic material, removing matrices and collections care.

The challenges presented by the finds included cracking, excavation scars, delamination and breaks caused by the inherent instability of the fossils and lavas, massive concretions or sediments attached to both fossils and lithics and issues relating to reconstruction or consolidation carried out on site.




Plaster jacketing to remove a micromorphology sample
We were very fortunate to collaborate with Dan Mainoya, a conservator and curator at the Natural History Museum in Arusha, Tanzania, and benefited from his long experience of working on material from Olduvai.



Dan, our Tanzanian colleague, shopping for conservation supplies in Arusha
The approaches developed focused on trialling stable, re-treatable adhesives and consolidants which would perform effectively in the challenging conditions of OGAP’s trenches but allow further treatment and refinement back in the controlled environment of the lab. We also tried some new methods of matrix removal, including a mobile air abrasive unit and weak acid gels.



Testing the mobile air abrasive unit at the Leakey camp


A fossilised suid tooth in need of some attention. It was lifted with a temporary facing of cyclododecane and long-fibred tissue

 
The suid tooth, after cleaning and consolidation back in the lab


Besides the opportunity to treat some stunning fossils and lithics from one of the most iconic archaeological sites in the world, we also had the privilege of meeting and working with many of the local Maasai people and returned to London with a lot of incredible beadwork jewellery!

With grateful thanks to the York Foundation for Conservation and Craftsmanship, which generously supported Rebecca's work at Olduvai www.conservationyork.org.uk

2 comments:

  1. Thank you for posting this! It was really interesting to read what you have been up to in Olduvai.

    I have to admit that I've never come across an Air Abrasion Unit before. The thought of perhaps one day having to use one seems quite daunting as well since I've always assumed that it would be more difficult to control the removal of concretions by an Abrasion Unit than it would by if you were to remove them by hand (by using for example a needle and pin vise).

    What kind of finds were you able to use the abrasion unit on?

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    1. Hi Iris,

      Thank you for your comments.

      Apologies for the delayed response. The air abrasive could be used without any abrasive powder for very gently work, or with sodium bicarbonate or aluminium oxide if more aggressive abrasive action were required. It worked very nicely for lifting off fine layers of sediment from fragile surfaces of lithics and even fossils with air only or sodium bicarb. If the surface of the tool could take it and the sediment was hard, though with a defined cleavage layer, the aluminium oxide could be used on lithics made from basalt and other lavas as well as quartzite, with some good results. We did, however, have some problems with our field generator as the compressor unit required more voltage that the generator could safely provide - so that's a valuable learning point for us all!

      With best wishes,
      Rebecca

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