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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

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!) - PowerPoint PPT Presentation

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Page 1: Stable and radiogenic isotopes in  Archaeology and Anthropology

Stable and radiogenic isotopes

in Archaeology and

Anthropology Henry P. Schwarcz

McMaster UniversityHamilton, Ontario, Canada

Christine White and Fred Longstaffe

University of Western OntarioLondon, Ontario, Canada

Page 2: Stable and radiogenic isotopes in  Archaeology and Anthropology

Definitions (loose!)

Anthropology: How people live (“culture”)

Archaeology: How people Lived (prehistoryand later)

Paleoanthropology: Who “people” were (evolution)

Page 3: Stable and radiogenic isotopes in  Archaeology and Anthropology

The samples: Bones, teeth

Time depth: 3 My to recent

Page 4: Stable and radiogenic isotopes in  Archaeology and Anthropology

Bone is a composite material consisting of: 60 wt% hydroxyapatite: HA

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

OXYGEN

+ 40% collagen (protein) N, C ATOMS

CARBON

Page 5: Stable and radiogenic isotopes in  Archaeology and Anthropology

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

Page 6: Stable and radiogenic isotopes in  Archaeology and Anthropology

Stable isotopes can help inform:

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

Paleoclimate: rain, drought, cold, heat

Migration: where did people come from?

Page 7: Stable and radiogenic isotopes in  Archaeology and Anthropology

0 10 20 30 40 50 60 70

years

M1

M2, P1, etc

M3

teeth

bones

hair, etc.

death

Stages of life recorded

Page 8: Stable and radiogenic isotopes in  Archaeology and Anthropology

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

Page 9: Stable and radiogenic isotopes in  Archaeology and Anthropology

0

5

10

15

20

25

-35 -30 -25 -20 -15 -10 -5

13C (l ) (PDB)

15N

(l

) (A

IR)

HERBIVORES

C3 PLANTS

CARNIVORES

C4 PLANTS

MARINE CARNIVORES

MARINE HERBIVORES

C4PLANTS

δ1

5N

(‰

) (

AIR

)

δ13C (‰) (PDB)

Page 10: Stable and radiogenic isotopes in  Archaeology and Anthropology

IsotopicAnalysis

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

[* mainly dietary protein (?)]

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

δ15N (collagen) = δ15N(diet) + 3 ‰[“trophic level effect”]

Page 11: Stable and radiogenic isotopes in  Archaeology and Anthropology

You are here

Marine consumers: how far would you go for sushi?

Page 12: Stable and radiogenic isotopes in  Archaeology and Anthropology

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

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

Seal

Page 13: Stable and radiogenic isotopes in  Archaeology and Anthropology

MALIBU site

Los Angeles

Page 14: Stable and radiogenic isotopes in  Archaeology and Anthropology

6

8

10

12

14

16

18

20

22

-22 -20 -18 -16 -14 -12 -10

Female

Male

Linear(Male)Linear(Female)

Walker & DeNiro

Same trend as on Channel Islands: females have higher trophic level

Schwarcz & Walker, in prep.

Page 15: Stable and radiogenic isotopes in  Archaeology and Anthropology

Travelling foods: Maize arrives in Ontario ~ AD 700

Maize from Mexico

Page 16: Stable and radiogenic isotopes in  Archaeology and Anthropology

After AD 700 maize replaced wild carbohydrates…

Page 17: Stable and radiogenic isotopes in  Archaeology and Anthropology

Paleoclimate

Isotopes as indicators of

Temperature: paleotemperaturesMollusk 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

Page 18: Stable and radiogenic isotopes in  Archaeology and Anthropology

Paleoclimate

Isotopes as indicators of

Temperature: paleotemperaturesMollusk 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

Page 19: Stable and radiogenic isotopes in  Archaeology and Anthropology

δ18O Paleotemperatures: Sclerochronology

Isotopic cycles in marine shell carbonates Season of occupation of midden-sites

Matthieu et al., Paleo3,2005

Wintercollection

Page 20: Stable and radiogenic isotopes in  Archaeology and Anthropology

Paleoclimate

Isotopes as indicators of

Temperature: paleotemperaturesMollusk 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

Page 21: Stable and radiogenic isotopes in  Archaeology and Anthropology

East Africa: calcite in soils

Levin et al., EPSL, 2004

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

Page 22: Stable and radiogenic isotopes in  Archaeology and Anthropology

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)

Page 23: Stable and radiogenic isotopes in  Archaeology and Anthropology

δ18O(bone)

δ18O(water)

δ18O bone tells us δ18O of local drinking water

Page 24: Stable and radiogenic isotopes in  Archaeology and Anthropology

δ18O of meteoric water varies regionally

Decreases with

Increasing latitude (poleward)

Distance from sea (source of water vapor)

Elevation

Temperature

Page 25: Stable and radiogenic isotopes in  Archaeology and Anthropology
Page 26: Stable and radiogenic isotopes in  Archaeology and Anthropology
Page 27: Stable and radiogenic isotopes in  Archaeology and Anthropology

Strontium isotope ratios

87Rb 87Sr t1/2 = 10 gy

.700 .705 .710 .715 87Sr/86Sr

limestonesyoung, low-Rb ------------------ old, high Rb

modern seawater

Page 28: Stable and radiogenic isotopes in  Archaeology and Anthropology

White, Price & Longstaffe: Anc. Mesoamerica 2007

seawater .7092

Page 29: Stable and radiogenic isotopes in  Archaeology and Anthropology

Moon Pyramid, Teotihuacan, Mexico

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

Page 30: Stable and radiogenic isotopes in  Archaeology and Anthropology

Possible sources: δ18O and 87Sr/86Sr

White, Price & Longstaffe, 2007

Page 31: Stable and radiogenic isotopes in  Archaeology and Anthropology

Teotihuacan

Page 32: Stable and radiogenic isotopes in  Archaeology and Anthropology

Conclusions

Childhood residences of all the sacrificial victims at the Moon Pyramidwere foreign to Teotihuacan and could be sourced to regions over Mesoamerica where Teotihuacanos areknown to have exerted influence.

White, Price & Longstaffe: Anc. Mesoamerica 2007

Page 33: Stable and radiogenic isotopes in  Archaeology and Anthropology

Forensics: The lady from Mammoth Lake

Page 34: Stable and radiogenic isotopes in  Archaeology and Anthropology

Native American or SoutheastAsian?

Hair was availablefor analysis

Page 35: Stable and radiogenic isotopes in  Archaeology and Anthropology

HAIR SAMPLE

Maize-rich diet

Page 36: Stable and radiogenic isotopes in  Archaeology and Anthropology

δ18O of water (SMOW, ‰)

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

Mammoth native tooth bone

Page 37: Stable and radiogenic isotopes in  Archaeology and Anthropology

DNA evidence: might be from a village in Oaxaca, Mexico

Page 38: Stable and radiogenic isotopes in  Archaeology and Anthropology

δ18O of water (SMOW, ‰)

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

Mammoth native tooth

Local water --> HA

Oaxaca village bone

Page 39: Stable and radiogenic isotopes in  Archaeology and Anthropology

Victim’s bone?

This part of her history is still unclear!

We need more rain data

Page 40: Stable and radiogenic isotopes in  Archaeology and Anthropology

Conclusions

Potential isotopic records:

birth childhood ?? late adult life

Isotopes can be used to trace trajectories of

1.Migration: O, C, N, Sr

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

Need “candidate sites”

Page 41: Stable and radiogenic isotopes in  Archaeology and Anthropology

Isotopes can be used to trace trajectories of

2.Diet: C, N isotopes: movement of hunters/gathererscoast<--->inland spread of cultigens

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

teeth drought seasonality temperature

Page 42: Stable and radiogenic isotopes in  Archaeology and Anthropology

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)