W. Müller, H. Fricke1, A.N. Halliday2, M.T. McCulloch
and Jo-Anne Wartho 3
1Department of Geology, Colorado College, Colorado Springs,
CO 80903, U.S.A.
2Department of Earth Sciences, ETH Zürich, CH-8092 Zürich,
Switzerland
3Department of Applied Geology, Curtin University of Technology,
Perth, Australia
The discovery of a perfectly preserved late
Neolithic human mummy in a glacier at the main Alpine ridge in
northern Italy during autumn of 1991 was a truly unexpected finding.
The 'Iceman' turned out to be ~5200 year old, and was found in-situ,
i.e. outside an arranged burial site, together with his entire
equipment. This finding thus provided the unique opportunity
to investigate circumstances of 'real' life during the late Neolithic.
One of the remaining open questions concerns the Iceman's origin,
particularly regarding his early life. Did he grow up in the
vicinity of the finding site or did he migrate to the area during
his adulthood, i.e. was he a local or migrant? Because of the
lack of pottery amongst the Iceman's equipment (substituted by
more appropriate lightweight equipment such as birch-bark containers),
his assignment to a contemporaneous culture either north or south
of the Alps based on pottery typology was impossible. Here we
utilize isotope geochemistry to answer the questions of origin
and migration of the Iceman.
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Combined radiogenic (Sr, Pb) and stable isotopic
(O) analysis of a comprehensive suite of samples formed at different
ontogenetic stages during the Iceman's life was conducted in
order to unravel his origin and migration, both regarding his
child- and adulthood. Investigated samples included enamel of
three teeth, dentine, cortical and trabecular bone and intestine
content. Soils from contemporaneous archaeological sites, river
waters and modern human teeth were used for comparison. The oxygen
isotope record of the Iceman's biominerals is consistent only
with his southern origin, both valid for his childhood (enamel)
and adulthood (bone). Areas north of the finding site (e.g. Ötztal)
can be excluded. Based on Sr and Pb isotopes, the Iceman grew
up on soils above gneisses and phyllites ('crystalline basement'),
whereas carbonate or volcanic soils can be excluded (Fig. 1).
This makes him a member of the local population from childhood
onwards, as the former lithologies mainly occur close to the
finding site. The isotopic compositions of bones suggest a different
food source during his last ~10 - 20 years of life, and indicate
the Iceman's migration during later life. This is currently investigated
further, also using single grain 40Ar/39Ar ages of white micas
recovered from the Iceman's intestine, as K/Ar and 40Ar/39Ar
white mica ages vary considerably in the area under investigation,
mainly as a result of strongly variable metamorphic overprint
following the Alpine orogeny. The small difference in _18O between
enamel and bone indicates that the Iceman did not spend protracted
periods of his later life at elevated altitudes, for example
in the southern Ötztal area, as in this case his bone oxygen
should be isotopically significantly lighter.
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