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14 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What is an isotope? |
An element with a different atomic mass |
Atomic mads |
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What is fractionation? |
When the proportions of an isotope changes in an environment. I.e. More 18-O than 16-O in the sea as the 16-O is less dense and would evaporate. |
Proportion |
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What is notation? |
Delta- change in Oxygen isotopes - 18-O Per mil depletion of an isotope- -12% Eg. Woolly mammoth tooth depletes 20% of isotope per thousand. |
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ICP-MS |
Instead of mass spectrometry (strips away particles)this is used ; plasma at 10K degrees is used as an ion source. -Technically challenging and expensive |
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What are diets determined by? |
12C, 13C, 14N, 15N. Through collagen, keratin Tracks proteins of diet only. |
Proteins. |
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Comparison of different types of plant |
3C- European I.e wheat/barley (-20 to -30% isotope depletion) •4C- Arid climates I.e. maize (-10 to -15% depletion) •CAM- tropical I.e. prickly pear |
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Nitrogen trophic levels |
Plants -> 0-1% Herbivore -> 3-5% Humans -> 6-10% |
Percentages. |
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How to track diet with C+N isotopes |
Looking at local fauna from that time period and March it to human samples. All herbivores will have 3-5% trophic levels. |
2. |
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Diet isotope example in Medieval York |
Monks buried in the East cemetery and laypeople in the southern cemetery at fisher gate (155 samples) showed monks ate more fish. |
Fisher gate |
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What determines paleo climate? |
16O and 18O. The warmer, the more isotope. The colder, the less. It is measured in marine shells, water from ice cores, tooth enamel. |
Oxygen |
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Benefits of oxygen isotopes in tooth enamel |
This |
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Example of herding at Catalhoyuk |
Sheep herd management and 18-O teeth enamel suggested birth seasons as teeth that had higher tooth carbonate at the root were born in summer. This is because 18O increases in heat. |
Teeth enamel |
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Amesbury archer |
30-35 16.2% carbonate, put him in the 5% category in the Neolithic; should have lived in the Alps from this. |
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Strontium Isotopes |
Decay process can be mapped of 87Sr. It results from decayed rubidium. I.e. bone is porous to Sr. If there is no difference in bone enamel and Dentine in teeth it means a local lived/died in the same region, when compared to plants containing it. |
Teeth enamel vs. Middle dentine. 87Sr |
