August 21, 2016

All the Neolithic and Chalcolithic of Ireland in a single paper

This entry should be a "quickie" because I wouldn't even know where to begin in order to analyze this comprehensive synthesis and not at all because it is a lesser study, all the oposite. Just to say that the average reader of this blog will want to read it, much more if they are Irish.

However I think that the paper raises some interesting questions regarding the chronology of "modern genetic Irishness" and the arrival of the Y-DNA lineage R1b to the island, which I cast below for your insights.

T. Rowan McLaughling et al., The Changing Face of Neolithic and Bronze Age Ireland: A Big Data Approach to the Settlement and Burial Records. Journal of World Prehistory 2016. Open accessLINK [doi:10.1007/s10963-016-9093-0]


This paper synthesizes and discusses the spatial and temporal patterns of archaeological sites in Ireland, spanning the Neolithic period and the Bronze Age transition (4300–1900 cal BC), in order to explore the timing and implications of the main changes that occurred in the archaeological record of that period. Large amounts of new data are sourced from unpublished developer-led excavations and combined with national archives, published excavations and online databases. Bayesian radiocarbon models and context- and sample-sensitive summed radiocarbon probabilities are used to examine the dataset. The study captures the scale and timing of the initial expansion of Early Neolithic settlement and the ensuing attenuation of all such activity—an apparent boom-and-bust cycle. The Late Neolithic and Chalcolithic periods are characterised by a resurgence and diversification of activity. Contextualisation and spatial analysis of radiocarbon data reveals finer-scale patterning than is usually possible with summed-probability approaches: the boom-and-bust models of prehistoric populations may, in fact, be a misinterpretation of more subtle demographic changes occurring at the same time as cultural change and attendant differences in the archaeological record.

The study should be very useful to anyone trying to understand the prehistory of Ireland, not the least because of its many maps and this extremely cool sequential maps video from pre-Neolithic times (5th millennium BCE) to the gates of the Bronze Age (early 2nd millennium BCE). Notice that in the Isles they tend to call "Bronze Age" to the Chalcolithic (Copper and Stone Age) and hence the title, which is a bit misleading.

An example of the very cool and highly informative maps and data you'll find in this study:
Fig. 3 - Map of Ireland showing Early Neolithic sites


Depopulation and resettlement? When?

An intriguing issue is the boom and bust cycles, particularly the almost total absence of signs of human activity around the end of the 4th millennium (3300-3000), suggesting maybe a depopulation after the first farmer colonization (?). There are clear booms around 4000, 3700, 3500, 2900, 2500 and since 2200 (Bell Beaker era). All this is something to chew about.

Particularly I'd raise the following question here: we know that a woman from c. 3400-3100 BCE (just at the depopulation gap?) was a typical Neolithic European, most similar to SE Spaniards and Sardinians, and that a man from c. 2200-1500 (Bell Beaker boom) was virtually identical to modern Irish and "British Celts" like Scots, Welsh and Cornish, carrying the common and controversial R1b patrilineage. 

The initial reading many of us made was that these new genetics may have arrived with Bell Beaker and that maybe Bell Beaker was more influential in terms demographic than we used to think, at least in Ireland. However, with this archaeological sequence on hand it seems at least reasonable to think that the major resettlement of an almost deserted Ireland happened after 3000 BCE but significantly earlier than the Bell Beaker phenomenon, which only reaches Northern Europe (Ireland included) c. 1500 BCE. What's your opinion?

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