Tracing prehistoric migration: Isotope analysis of bronze and pre-roman iron age coastal burials in Estonia

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DOI: 10.3176/arch.2016.1.01
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Abstract
There have been various explanations in archaeological literature about whether the earliest Bronze Age stone-cist graves and the first Pre-Roman Iron Age tarand graves in Estonia were built by locals or non-locals. As to possible immigrations, the stone-cist graves have been often related to Scandinavian populations, whilst early tarand graves allegedly had roots in eastern directions. The oldest known examples of these cemetery types are at Jõelähtme and Muuksi for stone-cist graves, and at Ilmandu and Kunda for early tarand graves, in the coastal zone of northern Estonia. In order to test the migration hypothesis we carried out a bioarchaeological study, measuring and mapping local biologically available Sr and O isotope ratios and analysing stable isotope signals of altogether eight individuals from these early stone-cist and tarand graves. The study material was chosen on the basis of the oldest AMS dates of skeletons available so far, or according to the earliest burial constructions in the cemeteries. Based on the comparison of local biologically available Sr and O isotopic baseline results and the results obtained from the individuals, we can talk about migrants in the case of two persons from Kunda and perhaps one from Muuksi, whilst most of the individuals analysed are of local origin. Thus, the idea of Early Metal Period migrations to Estonia from the surrounding regions is supported to some extent. However, the discussion of these migrations might turn out to be surprisingly different from what is expected on the basis of material culture. We also emphasise the importance of further analysis, especially mapping isotopic baseline data in the eastern Baltics, in order to draw further conclusions about the directions and extent of prehistoric migration in this region.
Estonian Journal of Archaeology, 2016, 20, 1, 3–32 doi: 10.3176/arch.2016.1.01
Ester Oras, Valter Lang, Eve Rannamäe, Liivi Varul, Marge Konsa,
Jana Limbo-Simovart, Gurly Vedru, Margot Laneman, Martin Malve
and T. Douglas Price
TRACING PREHISTORIC MIGRATION: ISOTOPE
ANALYSIS OF BRONZE AND PRE-ROMAN IRON
AGE COASTAL BURIALS IN ESTONIA
There have been various explanations in archaeological literature about whether the earliest
Bronze Age stone-cist graves and the first Pre-Roman Iron Age tarand graves in Estonia
were built by locals or non-locals. As to possible immigrations, the stone-cist graves have
been often related to Scandinavian populations, whilst early tarand graves allegedly had
roots in eastern directions. The oldest known examples of these cemetery types are at
Jõelähtme and Muuksi for stone-cist graves, and at Ilmandu and Kunda for early tarand
graves, in the coastal zone of northern Estonia. In order to test the migration hypothesis we
carried out a bioarchaeological study, measuring and mapping local biologically available
Sr and O isotope ratios and analysing stable isotope signals of altogether eight individuals
from these early stone-cist and tarand graves. The study material was chosen on the basis
of the oldest AMS dates of skeletons available so far, or according to the earliest burial
constructions in the cemeteries. Based on the comparison of local biologically available Sr
and O isotopic baseline results and the results obtained from the individuals, we can talk
about migrants in the case of two persons from Kunda and perhaps one from Muuksi, whilst
most of the individuals analysed are of local origin. Thus, the idea of Early Metal Period
migrations to Estonia from the surrounding regions is supported to some extent. However,
the discussion of these migrations might turn out to be surprisingly different from what is
expected on the basis of material culture. We also emphasise the importance of further analysis,
especially mapping isotopic baseline data in the eastern Baltics, in order to draw further
conclusions about the directions and extent of prehistoric migration in this region.
Ester Oras, Institute of History and Archaeology and Institute of Chemistry at the University
of Tartu, 18 Ülikooli St., 50090 Tartu, Estonia; ester.oras@ut.ee
Valter Lang, Institute of History and Archaeology at the University of Tartu, 18 Ülikooli St.,
50090 Tartu, Estonia; valter.lang@ut.ee
Eve Rannamäe, Institute of History and Archaeology at the University of Tartu, 18 Ülikooli St.,
50090 Tartu, Estonia; eve.rannamae@ut.ee
Liivi Varul, Institute of History and Archaeology at the University of Tartu, 18 Ülikooli St.,
50090 Tartu, Estonia; liivivarul@gmail.com
Marge Konsa, Institute of History and Archaeology at the University of Tartu, 18 Ülikooli St.,
50090 Tartu, Estonia; marge.konsa@ut.ee
Ester Oras et al.
4
Jana Limbo-Simovart, Independent Scholar; jana.limbo@gmail.com
Gurly Vedru, Archaeological Centre NGO, 6 Rüütli St., 10130 Tallinn, Estonia;
gurli11@mail.ee
Margot Laneman, Institute of History and Archaeology at the University of Tartu,
18 Ülikooli St., 50090 Tartu, Estonia; margot.laneman@ut.ee
Martin Malve, Institute of History and Archaeology at the University of Tartu, 18 Ülikooli St.,
50090 Tartu, Estonia; martin.malve@ut.ee
T. Douglas Price, Laboratory for Archaeological Chemistry, University of Wisconsin-Madison,
Madison WI 53706, USA; tdprice@wisc.edu
Introduction
The past human migration has been one of the most intriguing and fascinating
subjects in archaeological research for decades. Discussions of prehistoric
migrations in Baltic archaeology have traditionally relied on material culture,
physical anthropology and linguistic evidence. Different ‘anthropological types’,
burial practices, burial goods and burial structures have been used to prove or
disprove the movement of people within, but also to and from the eastern regions
of the Baltic Sea and very often these have ended up in interpretations with
strong ethnic connotations (see e.g. EREA 1956; Schmiedehelm & Laul 1970;
Jaanits et al. 1982; Denisova et al. 1985; Michelbertas 1986; Lietuvių etnogenezė
1987; Tvauri 2003; 2007). In those discussions there still remains a question
whether one can talk about a movement of people or perhaps an exchange of
ideas/objects instead.
Recent decades have provided us with several scientific methods that help to
create better-argued statements about past migrations, their scale, motives and
directions. The studies of ancient DNA (aDNA) are no doubt prolific enquiries in
this field, especially when it comes to large-scale and long-term human evolution,
demographics and movements (Richards et al. 2000; Hofreiter et al. 2001; Richards
2003; Haak et al. 2008; Chatters et al. 2014). The second largest field of analysis
evolves around stable isotope studies. This includes tracing migration via in-
depth dietary studies (mainly the analysis of δ13C and δ15N) of different bone
tissues that on the basis of their different formation processes in time allow
adding temporal scale to the analysis (e.g. Eriksson 2007; Fischer et al. 2007;
Eriksson & Lidén 2013). The most widely used method, however, remains
strontium and oxygen isotope analysis (87Sr/86Sr and δ18O, see below for details
and references) which has been little employed in the eastern Baltic region (see
Price et al. forthcoming). This method forms the basis for this article in which we
discuss its application on the earliest stone graves in Estonia.
Stone-cist graves of the Late Bronze and early Pre-Roman Iron Age (ca 1200–
400 BC) are the first above-ground stone burial structures that appeared in the
area of Estonia. Early tarand graves emerged in the last centuries of the Bronze
Age and persisted through the Pre-Roman Iron Age (ca 800 BC – AD 100). Both
grave types turn up mostly in the coastal regions of Estonia, being almost absent
in inland areas. Their origin and distribution has been discussed on the basis
Tracing prehistoric migration
5
of both structural peculiarities and artefactual material and explained either via
migrations, cultural influences or local developments without remarkable movement
of people (see below). We set out a pilot project to contribute to this discussion
with rather different archaeological evidence, i.e. the biological remains of the
deceased themselves by analysing strontium and oxygen isotopes in their tooth
enamel. Four analysed persons out of eight had no grave goods; the items of the
other four are briefly discussed below in terms of their origin. However, we
stress herewith that the origin of grave goods cannot be taken as an evidence of
the origin of buried people. The main aim of this paper is to add new material,
independent of cultural belongings, concerning the origin of the past people.
Pairs of the earliest cemeteries of their kind were chosen for the analysis:
Jõelähtme and Muuksi for stone-cist graves, Ilmandu and Kunda for early tarand
graves (Fig. 1; Table 1). We chose our material according to the earliest AMS dates
of the deceased. We also took into account relative chronology of the cemetery
aiming for the earliest burial structures. Where possible, imported goods were also
considered, though radiocarbon dates and building chronology was prioritised when
choosing the material for the analysis. It needs to be emphasised that due to the
small number and intrinsic inexactness of radiocarbon dates and the circumstance
that the cemeteries are not entirely excavated, we cannot be certain that the selected
individuals belonged to the first generation of grave-builders. Therefore, our
results cannot provide an all-conclusive answer whether the discussed grave types
Fig. 1. Map of sites discussed in the article.
Ester Oras et al.
6
Tracing prehistoric migration
7
arrived to Estonia with migrants. Nevertheless, they shed new light upon the
origin of the people according to the currently available oldest AMS dates in
those cemeteries and, hopefully, encourage further research on the subject.
Our further aim is to draw attention to the importance of incorporating archaeo-
logical material and scientific techniques to tackle grand-scale archaeological
narratives. We exemplify the importance of interdisciplinary approach to archaeo-
logical material and show how questioning bold archaeological problems can
trigger a need for further enquiries, which make an important contribution to the
overall development of local archaeological research.
Estonian coastal burials and the question of migrations
in Bronze and Pre-Roman Iron Age
Stone-cist graves are above-ground structures that have a stone-cist (or several
cists) in the middle and one or several circular stone walls around it (them), all
covered with stones (see more in Lang 2007, 147 ff.). Although these structures
were seemingly built for individual burials, the actual number of burials can vary
from two-three to twenty or even more but usually they scatter over long periods
in chronological terms. Inhumation is the most common form of burial but
cremations also occur, particularly outside the cists. Grave goods are rather rare,
consisting mostly of ornaments and small tools/everyday items. By their structure
and burial practices, the Estonian stone-cist graves very much resemble stone
barrows in central Sweden and on Gotland in the earlier part of the Bronze Age,
though they are smaller in size and later in date.
For early archaeologists, such as Artur Spreckelsen (1927), Adolf Friedenthal
(1931) and Birger Nerman (1933), the distribution of stone-cist graves was
a clear sign of direct migration of the Scandinavians from Gotland or eastern
central Sweden towards the eastern shore of the Baltic Sea. This explanation
was then accepted by Harri Moora as well, although he also considered cultural
influences from East Prussia quite likely (Moora 1932). In the 1950s, the Finnish
archaeologist Carl F. Meinander (1954) explained this phenomenon as a result
of long-lasting cultural influence, which first and together with some people
distributed from Scandinavia to coastal Finland and next from coastal Finland
to northern Estonia. Reaching Estonia, this cultural impact did no longer contain
so much direct Scandinavian elements, but indeed was more or less a Finnic
occurrence. This explanation also achieved much support in Estonia since the
1950s, the more so because similar ideas had already been presented earlier by
Artur Vassar (1943). At those times, within the Marxist paradigm in Soviet Estonian
archaeology, migratory explanations – particularly when concerning probable
immigrations from the west – were not favoured (with a few exceptions) and local
socio-economic developments were preferred instead (e.g. Jaanits et al. 1982, 161).
Today, a few direct migrations from Scandinavia as initiative events for the
distribution of stone-cist graves in coastal Estonia are considered plausible again
(Lang 2011; 2015).
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