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Tracing the Source of the Elephant And Hippopotamus Ivory from ...

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ecause usually <strong>the</strong> enamel was removed by humans (possibly before shipping even), or<br />

by nature, as <strong>the</strong> enamel tends to wear <strong>of</strong>f with use.<br />

The availability <strong>of</strong> strontium isotope data in <strong>the</strong> geological literature for some<br />

regions leaves something to be desired. The next step would be to search out<br />

unpublished data by contacting mining companies and governmental geological surveys.<br />

In general <strong>the</strong> geological literature is biased, understandably, towards answering research<br />

questions <strong>of</strong> interest to geologists. These tend to concern unusual formations or<br />

processes. But <strong>the</strong> geological literature should not be solely depended on anyway,<br />

because <strong>of</strong> <strong>the</strong> potential differences between biologically-available strontium and<br />

geological strontium.<br />

The stable carbon, oxygen, and nitrogen isotopes did not provide isotopic<br />

signatures like those reported by van der Merwe et al. (1990) and Vogel et al. (1990),<br />

primarily because <strong>the</strong> oxygen and nitrogen isotopes were not retrievable or potentially<br />

contaminated by diagenetic processes. These isotopes were not expected to differentiate<br />

source areas, since <strong>the</strong>y are based on diet and environmental factors, and <strong>the</strong>refore<br />

populations <strong>from</strong> geographically separated regions could have <strong>the</strong> same isotopic<br />

signature. XRD should also be conducted on apatite samples to determine to what degree<br />

<strong>the</strong> burial environment has affected <strong>the</strong> integrity <strong>of</strong> <strong>the</strong> isotopic signal.<br />

Strontium isotope ratios, because <strong>the</strong>y are based on <strong>the</strong> geology <strong>of</strong> <strong>the</strong> region, are<br />

<strong>the</strong>refore <strong>the</strong> best suited for provenance studies. O<strong>the</strong>r isotopes, such as lead (Pb) and<br />

neodymium (Nd), are also incorporated into bone and ivory <strong>of</strong> animals <strong>from</strong> <strong>the</strong><br />

environment based on <strong>the</strong> underlying bedrock geology. In <strong>the</strong> future strontium isotopes<br />

should be analyzed alongside lead and neodymium, as <strong>the</strong> more isotopes available to<br />

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