Reconstructing Middle and Upper Paleolithic human mobility in Portuguese Estremadura through laser ablation strontium isotope analysis
Bethan Linscott, Alistair WG Pike, Diego E Angelucci, Matthew J Cooper, James S Milton, Henrique Matias & João Zilhão 2023
PNAS doi 10.1073/pnas.2204501120
Laser ablation MC-ICP-MS allows in situ Sr*data to be obtained for incrementally formed bio-apatites (enamel) with extremely high spatial resolution.
Here we provide a large-scale application of the method,
we compare the mobility & subsistence behavior of mid- & UP humans in the same landscape.
These remains & the fauna analyzed alongside come from the Almonda karst system.
Data suggest:
-- regional mid-Paleolithic individuals roamed across a subsistence territory of c 600 km2,
-- UP individuals moved seasonally, and exploited a smaller territory of c 300 km2.
Abstract
Understanding mobility & landscape use is important in reconstructing subsistence behavior, range & group size,
it may contribute to our understanding of e.g. the dynamics of biological & cultural interactions between distinct populations of UP humans.
But studies using traditional Sr*analysis are generally limited to identifying locations of childhood residence or non-local individuals,
they lack the sampling resolution to detect movement over short time-scales.
Here, using an optimized methodology, we present highly spatially resolved 87/86Sr measurements,
these were made by laser ablation multi-collector inductively coupled plasma mass spectrometry along the growth axis of the enamel of
- 2 MIS-5b, mid-Paleolithic Hn teeth (Gruta da Oliveira),
- a Tardi-glacial, Late-Magdalenian Hs tooth (Galeria da Cisterna),
- associated contemporaneous fauna from the Almonda karst system, Torres Novas.
Sr*mapping of the region shows extreme variation in 87/86Sr:
values range from 0.7080 to 0.7160 over a distance of c 50 km,
this allows short-distance (& arguably short-duration) movement to be detected.
We find:
- the early-mid-Paleolithic individuals roamed across a subsistence territory of c 600 km2,
- the Late-Magdalenian individual parsimoniously fits a pattern of limited, probably seasonal movement along the right bank of the 20-km-long Almonda River valley, between mouth & spring, exploiting a smaller territory of c 300 km2.
Are the differences in territory size due to an increase in population density during the Late UP?
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This beautifully confirms my hypothesis that Hn seasonally followed the river inland. :-) Salmon trek??
Hn stone tools, pachy-osteo-sclerosis (shallow-diving) & huge brain (DHA) show most of their food still came from coastal cray- & esp. shellfish.
https://www.gondwanatalks.com/l/the-waterside-hypothesis-wading-led-to-upright-walking-in-early-humans/
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The Intriguing Lifestyle of Neanderthals
– Tooth Enamel Reveals New Clues
University of Southampton 13.5.23
An internat.group (Univ.Southampton) has offered a fascinating look into the hunting strategies and dietary habits of Hn & other human groups in W-Europe.
They scrutinized the chemical composition preserved within tooth enamel, to reconstruct the lifestyle of prehistoric individuals in relation to their local environment.
The study focused on the Almonda Cave network, near Torres Novas in the heart of Portugal, nearly 100 ka.
They show
- Hn in the region were hunting fairly large animals across wide tracts of land,
- Hs in the same location 10s of 1000s of years later survived on smaller creatures in an area half the size.
Sr*isotopes in rocks gradually change over millions of years because of radio-active processes:
they vary from place to place, depending on the age of the underlying geology.
As rocks weather, the isotopic ‘fingerprints’ are passed into plants via sediments,
they make their way along the food-chain – eventually passing into tooth enamel.
In this study, archaeologists used a technique that laser samples enamel and makes 1000s of individual Sr*measurements along the growth of a tooth-crown.
Samples were taken from 2 Hn c 95 ka & from a more recent Hs c 13 ka (Magdalenian).
They also looked at isotopes in the tooth enamel of animals found in the cave system.
Alongside Sr*, they measured O*isotopes, which vary seasonally from summer to winter, to establish where the animals ranged across the landscape & in which seasons they were available for hunting.
They showed:
- the Hn (who were targeting large animals)(?? --mv) could(??) have hunted wild goats in the summer,
horses, red deer & an extinct rhino were available all year round within c 30 km,
- the Magdalenian individual showed a different pattern of subsistence, with seasonal movement of c 20 km from the Almonda caves to the banks of the Tagus River,
his diet included rabbits, red deer, wild goat & freshwater fish.
The researchers approximated the territory of the 2 different human groups, revealing contrasting results:
- the Hn obtained their food over c 600 km2,
- the Magdalenian individuals occupied a much smaller territory, c 300 km2..
Bethan Linscott:
“Tooth enamel forms incrementally,
it so represents a time series that records the geological origin of the food an individual ate.
Using laser ablation, we can measure the variation of Sr*isotopes over the 2 or 3 years it takes for the enamel to form.
By comparing the Sr*isotopes in the teeth with sediments collected at different locations in the region, we were able to map the movements of the Hn & the Magdalenian individual.
The geology around the Almonda caves is highly variable, making it possible to spot movement of just a few kms.”
Alistair Pike (supervisor):
“This study shows just how much science has changed our understanding of archaeology in the past decade.
--Previously, the lives & behaviors of past individuals were limited to what we could infer from marks on their bones, or the artifacts they used.
--Now, using the chemistry of bones & teeth, we can begin to reconstruct individual life histories, even as far back as the Hn.”
João Zilhão (co-author, Univ.Lisbon) led the excavation of the Almonda caves:
“The difference in the territory size between the Hn & Magdalenian individuals is probably related to population density.
- With a rel.low population, Hn were free to roam further to target large prey spp, e.g. horses, without encountering rival groups.
- By the Magdalenian period, an increase in population density reduced available territory:
human groups had moved down the food-chain, to occupy smaller territories, hunting mostly rabbits & catching fish on a seasonal basis.”