National Museums Scotland hold around 250,000 Palaeobiological specimens in a modern purpose built, environmentally controlled store. The collection covers all the major groups of fossil invertebrates, plants and trace fossils. There are the historic collections of early pioneers of Scottish Palaeobiology such as Hugh Miller and Charles Peach as well as world class collections of Palaeozoic fishes and early tetrapods. Members of the Palaeobiology Section of the Department of Natural Sciences at NMS are involved in internationally important research projects, such as TW;eed [Tetrapod World: early evolution and diversity] Project. Vicen Carrió ACR is the conservator and preparator of the Palaeobiology Section.
Vicen’s responsibilities include the conservation and preparation of fossils, providing advice on geological conservation and preparation techniques to other departments within the museum and to visitors working on the NMS collections. On a [pre- Covid 19] visit to Vicen’s conservation lab, I had the privilege to view specimens from the collection and learn a little about the fascinating world of Geology Conservation. It is extremely difficult to grasp the age of these objects, many form the Palaeozoic period which was between 543-251 million years ago. Scotland is rich in specimens of early life on earth from this period such as Gyracanthus [extinct genus of fish with very long, round, sculpted fin- spines].
Conservation of Specimens from Historic Collections
Care of historic geology collections is a very interdisciplinary area of conservation because of the variety of material that is encountered: paper labels attached to the specimens, wood, plaster moulds and casts, glass, pigments, nails, minerals, plastic and varnishes.
The Gyracanthus spines can be between 9cm -50cm long and are fragile. When collected they were often found in pieces. Inappropriate support and handling make the spines weak and prone to stress fractures and breakages. The deterioration of historic treatments using non archival adhesives can also lead to the failure of joints, as well as a lack of support underneath the specimen with the consequence of collapse. Vicen stressed the importance of inert materials in the construction of custom made supports for the specimens [Ethafoam, Plastazote, Corex or honeycomb cardboard or aluminium] and the use of appropriate, reversible adhesives.
The historic collections contain fossils in a variety of styles of display with many pros and cons. Some materials have been imbedded in plaster, fixed to glass plates or encased in wood. The hygroscopic nature of the plaster and wood can result in cracking of the specimens [as seen above]. Removal of these inappropriate supports is necessary to preserve the heritage for the future.
Working in the Field – The TW;eed Project
The TW;eed Project was a NERC funded project to study newly discovered tetrapod [four-legged animal] fossils that were found in the Scottish Borders. The fossils are from the earliest Carboniferous, a time when very little was known about life on earth and when tetrapods had just ventured to land. The poster below details the consolidation of wet specimens from the river bed and the preparations necessary prior to transportation of the fossils back to the museum conservation lab.
Uncovering Recently Discovered Fossils from Rock Substrate
The skill and experience involved in the excavation of newly discovered fossils from rocks cannot be underestimated. This work is undertaken very slowly under high magnification as the dimensions and shape of the fossil within the rock are only revealed as the substrate is carefully removed. Knowledge of the fossil’s anatomy and the characteristics of the encasing rock are essential as the matrix can break at weak points.
Rock Specimens from Scotland
The map required some of the physical techniques needed in geological preparation such as precise cutting to shape and the use of a combination of adhesives. The rocks when grained and mixed with some adhesives camouflage or enhance different areas of the map.
Vicen is experienced in a variety of physical and chemical techniques including making acetate peels, moulding and casting, acid preparation, field techniques, thin section, polishing and preventative conservation.
Vicen Carrió ACR studied Biology at the University of Valencia, Spain, before moving to Edinburgh in 1992. Having first worked with Professor Euan Clarkson, University of Edinburgh, in Silurian gastropod fossils she gained funding to study the conservation of fossils, minerals and rocks. Since 1997 she has developed her career in geological conservation and has undertaken research in different areas of the collection, presenting numerous talks at conferences and seminars nationally and internationally. These conferences have helped her to develop new techniques in conservation and to keep up to date with new products and technology as they are developed. She now has an international reputation as a geological conservator, being invited as key speaker to international conferences in her field.