Finding radiogenic Sr-isotope biospheres : can a home in Britain be found for people with high 87Sr/86Sr?
With increasing regularity archaeological humans with 87Sr/86Sr >0.714 are being excavated in Britain and are difficult to explain or identify possible places of origin. The main aim of this thesis was to identify any geological or anthropological reasons for their high 87Sr/86Sr values. Therefore, plant 87Sr/86Sr data has been obtained from several Precambrian lithologies and igneous intrusions in Britain with the aim of identifying values >0.714. Only 20 of the 151 samples measured recorded values >0.714. It was found that biosphere 87Sr/86Sr values >0.714 represented only 10% of all known British Sr-isotope biosphere data and only ~2.8% of the area of Britain. They are thus numerically and spatially rare and can also be considered agriculturally marginal for archaeological populations. Unexpectedly, plant samples collected from ancient woodlands were found to have elevated values by +0.002 compared to plant samples collected from unforested land on the sedimentary Triassic bedrock of central England. Further work is needed to replicate this result and to establish if the same trend is found on other bedrock lithologies. This finding could have major implications for how biosphere and human 87Sr/86Sr data
Johnson, Lucie Jade
Finding radiogenic Sr-isotope biospheres : can a home in Britain be found for people with high 87Sr/86Sr?. With increasing regularity archaeological humans with 87Sr/86Sr >0.714 are being excavated in Britain and are difficult to explain or identify possible places of origin. The main aim of this thesis was to identify any geological or anthropological reasons for their high 87Sr/86Sr values. Therefore, plant 87Sr/86Sr data has been obtained from several Precambrian lithologies and igneous intrusions in Britain with the aim of identifying values >0.714. Only 20 of the 151 samples measured recorded values >0.714. It was found that biosphere 87Sr/86Sr values >0.714 represented only 10% of all known British Sr-isotope biosphere data and only ~2.8% of the area of Britain. They are thus numerically and spatially rare and can also be considered agriculturally marginal for archaeological populations. Unexpectedly, plant samples collected from ancient woodlands were found to have elevated values by +0.002 compared to plant samples collected from unforested land on the sedimentary Triassic bedrock of central England. Further work is needed to replicate this result and to establish if the same trend is found on other bedrock lithologies. This finding could have major implications for how biosphere and human 87Sr/86Sr data
finding isotope home_britain find people high increase regularity archaeological human excavate britain difficult explain identify_possible place_origin main_aim identify geological anthropological reason high value therefore plant data_obtain several intrusion britain aim_identify value sample measure record value find value represent know british isotope data area britain thus numerically spatially rare also_consider marginal archaeological_population unexpectedly plant sample_collect ancient woodland find elevate value compare plant sample_collect land sedimentary bedrock central england work need replicate establish trend find bedrock finding could major implication human data