Heritage Cases

Application to export shell samples for isotope analysis 2017

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ProposalDescription: 

We are applying for a permit to temporarily export 11 whole and fragmentary opercula of Turbo sarmaticus marine snail shells for the purpose of carbon and oxygen isotopic sampling. Sampling will take place at Oxford University, UK. The samples collected from the surface of each operculum will be minimally invasive and will not alter the gross dimensions of the shell fragments.

Expanded_Motivation: 

Much of the robust evidence for the early emergence of modern human behaviour, including consistent use of marine resources, in the African Middle Stone Age comes from a series of sites along the southern Cape coastline, South Africa. Both the nature of marine resource use and the climatic and environmental contexts of these sites from the Last Interglacial into Marine Isotope Stages 4 and 3 has been a long-standing focus of attention. During my doctoral studies (completed in Nov 2016), I constructed a seasonally-resolved record of Pleistocene and Holocene sea surface temperatures (SSTs) for the south coast of South Africa using oxygen isotope analyses of archaeological shells from sites including Nelson Bay Cave, Pinnacle Point 5-6 and Klasies River (Loftus, 2016; Loftus et al., submitted). However, none of these sites preserved shells from MIS3 aged deposits, leaving a crucial time gap in my record. The shells from Knysna Eastern Heads Cave 1 will help to fill this gap, and round out this seasonal climate record across the last glacial cycle. Most importantly, these samples will allow us to connect the records from the Middle and Later Stone Age sites, illuminating the cultural and economic changes that occurred across this key transition period. Three pieces of analytical equipment are essential for these analyses, and are not available to this project in South Africa. Firstly, the high-resolution, and very time-consuming, sampling protocol requires abundant time on a microscope-mounted micromill. One is available at the University of Oxford, in collaboration with the Department of Earth Sciences, with no charges levied. Secondly, each sample must be evaluated for recrystallization, using a method developed by Emma Loftus using an FTIR-ATR instrument at the Research Laboratory for Archaeology in Oxford (Loftus et al., 2015). Finally, a mass spectrometer with a carbonate device capable of measuring such small samples is not available in South Africa.

ApplicationDate: 

Thursday, May 25, 2017 - 21:41

CaseID: 

11114

OtherReferences: 

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ReferenceList: 

Citation Type Date Retrieved
Galimberti M, Loftus E, Sealy JC .2017. Investigating δ18O of Turbo sarmaticus (L. 1758) as an indicator of sea surface temperatures. Palaeogeogr Palaeoclimatol Palaeoecol. Journal
Loftus E (2016) Sea surface temperatures from oxygen isotopes in marine molluscs in Middle and Later Stone Age sites, South Africa. Dissertation (University of Oxford). Other Publication
Loftus E, Rogers K, Lee-Thorp JA (2015) A simple method to establish calcite:aragonite ratios in archaeological mollusc shells. J Quat Sci 30(8):731–735. Journal
Loftus E, Sealy J, Leng M, Lee-Thorp J. A late Quaternary record of seasonal sea surface temperatures off southern Africa. In review, Quat Sci Rev Journal
Images
Excavated area of KEH Cave 1
 
 

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