Tag Archives for mollusc collections

Feeling Older than Your Age? The Importance of Museum Collections for Radiocarbon Dating, and a Request for Collections containing Bivalves Collected Before 1950 from the UK

Written by Rachel Wood, Associate Professor, Oxford Radiocarbon Accelerator Unit, School of Archaeology, University of Oxford.

Radiocarbon dating is routinely used to work out the age of archaeological and palaeontological sites, and often pops up in news articles and TV dramas. But some substantial problems remain. One of these is the calibration process, which allows us to convert the ratio of 14C (“radiocarbon”) and 12C (the common stable form of carbon) to an age estimate. This is particularly challenging when we are trying to date marine shells or any animal that has eaten food from the marine system. This means that it can be difficult for us to get an accurate age for a sample that should be straightforward – for example, the skeleton of Medieval person or a Mesolithic dog.

The Oxford Radiocarbon Accelerator Unit is starting a project looking for samples of marine shells to help resolve this problem (Fig. 1). Natural history collections in museums are key to its success, and we would be very grateful to hear if anyone has a collection of pre-1950 marine bivalve shells.

Figure 1. Marine bivalves, suitable for helping us to calibrate radiocarbon dates. Please let us know if you have similar material that can be analysed by sampling a small strip from the edge. (Photo Peter Ditchfield, Courtesy Oxford University Museum of Natural History)

The Problem

At school, we are taught that radiocarbon dating works because radiocarbon decays radioactively at a known rate. By comparing the amount of 14C to a stable form of carbon called 12C, we can work out the age of a sample (Fig. 2). This is true, but only partially so because the starting 14C:12C varies. To get around this problem, we need to calibrate radiocarbon dates. Most 14C is produced in the upper atmosphere, and is incorporated into plants by photosynthesis and then passed through the food chain. This means, that if someone is eating terrestrial food – they will have a similar 14C:12C ratio in their bodies as in the atmosphere.

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‘Marvellous Molluscs’ – Increasing Accessibility, Improving Storage & Unlocking Research Potential At The University Of Aberdeen

Written by Hannah Clarke, Assistant Curator (Collections Access), University of Aberdeen.

In April 2021, The University of Aberdeen’s Zoology Museum, with support from NatSCA’s Bill Pettit Memorial Award, undertook a year-long project to rehouse and improve the accessibility of the University’s mollusc collection.

The collection comprises approximately 2550, mostly British specimens, collected from the 1840s to the 1970s. The specimens were gifted to the museum by former students, academic staff, and amateur shell collectors, they also include several specimens from as far afield as the Pacific, Africa, China, Madagascar, America, and Canada.

The molluscs form part of the University’s extensive Zoology Collections, which are recognised as being of National Significance. As such, we are constantly striving to improve access to these collections, and the ‘Marvellous Molluscs’ Project aimed to do just that.

Assistant Curator, Hannah Clarke, identifying storage issues in specimen cupboards.

Having identified the collections both in storage and on display, a project plan was created that would tackle not only the rehousing, but also the documentation of the specimens on the museum database. The majority of specimens were poorly stored several layers deep in drawers, had outdated taxonomy, and lacked any database records or collections data.

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