Stable and radiogenic isotopes in
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Stable and radiogenic isotopes in Archaeology and Anthropology. Henry P. Schwarcz McMaster University Hamilton, Ontario, Canada Christine White and Fred Longstaffe University of Western Ontario London, Ontario, Canada. Definitions (loose!)

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Stable and radiogenic isotopes in Archaeology and Anthropology

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Stable and radiogenic isotopes in

Archaeology and Anthropology

Henry P. Schwarcz

McMaster University

Hamilton, Ontario, Canada

Christine White and

Fred Longstaffe

University of Western Ontario

London, Ontario, Canada


Definitions (loose!)

Anthropology: How people live (“culture”)

Archaeology: How people Lived (prehistory

and later)

Paleoanthropology: Who “people” were

(evolution)


The samples: Bones, teeth

Time depth: 3 My to recent


Bone is a composite material

consisting of:

60 wt% hydroxyapatite: HA

Ca5(PO4, CO3 ) 3 (OH, CO3)

OXYGEN

CARBON

+ 40% collagen (protein)

N, C ATOMS


Diagenesis: when bad things happen to good bones

During burial:

Collagen degrades: C/N ~ 3.2?

Hydroxyapatite “crystallinity” increases

O, C isotopic exchange with soil-water?

We can test for these and exclude bad bones


Stable isotopes can help inform:

Paleodiet: “you are what you eat + x ‰”

Migration: where did people come from?

Paleoclimate: rain, drought, cold, heat


Stages of life recorded

M1

teeth

M2, P1, etc

M3

bones

hair, etc.

death

0 10 20 30 40 50 60 70

years


PALEODIET

Nutrient molecules:

protein: C, N, H, O

Fat: C, H, O

Carbohydrate: C, H, O

δ13C, δ15N, δ18O of each nutrient varies

depending on the source


δ15N (‰) (AIR)

C4

PLANTS

δ13C (‰) (PDB)


IsotopicAnalysis

δ13C(bone collagen) = δ13C (food*) + 5‰

[* mainly dietary protein (?)]

δ13C (CO3-apatite) ≈δ13C (food) + 11 ‰

δ15N (collagen) = δ15N(diet) + 3 ‰

[“trophic level effect”]


Marine consumers: how far would you go for sushi?

You are here


Walker and DeNiro Am. J. Phys Anth., 1986

Seal

Conclusion: Everyone was eating seal meat, but more in the islands


Los Angeles

MALIBU site


Schwarcz & Walker, in prep.

Walker & DeNiro

Same trend as on Channel Islands:

females have higher trophic level


Travelling foods: Maize arrives in Ontario ~ AD 700

Maize from Mexico


After AD 700 maize replaced wild carbohydrates…


Paleoclimate

Isotopes as indicators of

Temperature: paleotemperatures

Mollusk shells in middens

Speleothems

Teeth, bones

Humidity, Rainfall

δ13C C3 vs C4 plants (wet vs dry)

δ15N in collagen: rainfall (aridity)

δ18O cycles in tooth enamel: seasonality of rain


Paleoclimate

Isotopes as indicators of

Temperature: paleotemperatures

Mollusk shells in middens

Speleothems

Teeth, bones

Humidity, Rainfall

δ13C C3 vs C4 plants (wet vs dry)

δ15N in collagen: rainfall (aridity)

δ18O cycles in tooth enamel: seasonality of rain


δ18O Paleotemperatures: Sclerochronology

Isotopic cycles in marine shell carbonates 

Season of occupation of midden-sites

Winter

collection

Matthieu et al., Paleo3,2005


Paleoclimate

Isotopes as indicators of

Temperature: paleotemperatures

Mollusk shells in middens

Speleothems

Teeth, bones

Humidity, Rainfall

δ13C C3 vs C4 plants (wet vs dry)

δ15N in collagen: rainfall (aridity)

δ18O cycles in tooth enamel: seasonality of rain


East Africa: calcite in soils

C3,moist-------------------C4, hot,dry

Levin et al., EPSL, 2004


Migration: O and Sr isotopes

Where does he/she come from?

Isotopic labels can tell us something

About place of origin (but not everything)

These are questions in

Archaeology/Anthropology

Forensic Science (murder victims)


δ18O bone tells us δ18O of local drinking water

δ18O(bone)

δ18O(water)


δ18O of meteoric water varies regionally

Decreases with

Increasing latitude (poleward)

Distance from sea (source of water vapor)

Elevation

Temperature


Strontium isotope ratios

87Rb  87Sr t1/2 = 10 gy

limestones

young, low-Rb ------------------ old, high Rb

.700 .705 .710 .715

87Sr/86Sr

modern seawater


White, Price & Longstaffe: Anc. Mesoamerica2007

seawater

.7092


Moon Pyramid, Teotihuacan, Mexico

In use from AD 1 to 650: Sacrificial victims…from where?


Possible sources: δ18O and 87Sr/86Sr

White, Price & Longstaffe, 2007


Teotihuacan


Conclusions

Childhood residences of all the

sacrificial victims at the Moon Pyramid

were foreign to Teotihuacan and

could be sourced to regions over

Mesoamerica where Teotihuacanos are

known to have exerted influence.

White, Price & Longstaffe: Anc. Mesoamerica 2007


Forensics: The lady from Mammoth Lake


Hair was available

for analysis

Native American or SoutheastAsian?


HAIR SAMPLE

Maize-rich diet


Mammoth

native

tooth

bone

-14 -12 -10 -8 -6 -4

δ18O of water (SMOW, ‰)


DNA evidence: might be from a village in

Oaxaca, Mexico


Local water --> HA

Mammoth

native

Oaxaca village

tooth

bone

-14 -12 -10 -8 -6 -4

δ18O of water (SMOW, ‰)


This part of her history is still unclear!

Victim’s bone?

We need more rain data


Conclusions

  • Potential isotopic records:

  • birth  childhood ?? late adult life

  • Isotopes can be used to trace trajectories of

    • Migration: O, C, N, Sr

    • But not high specificity: 100’s - 1000’s km2

    • Need “candidate sites”


  • Isotopes can be used to trace trajectories of

  • Diet: C, N isotopes:

  • movement of hunters/gatherers

  • coast<--->inland

  • spread of cultigens

  • 3. Climate: O, C in soils, animal bone + teeth

  • drought

  • seasonality

  • temperature


Acknowledgements

  • Tracy Prowse

  • Phil Walker

  • Martin Knyf

  • Natural Sciences and Engineering Research Council of Canada (NSERC)

  • Social Sciences and Humanities Research Council of Canada (SSHRC)


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