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

Figure 59: Map of the Kenya and Ethiopia rifts, showing the distribution of Tertiary-
Recent volcanism, and the MB, TC, and RCM. The curved solid lines denote the extent
of the Ethiopian and east African plateaus (Rogers et al. 2000: 389, figure 1).
Talbot et al. (2000) in Figure 58 above. Specific Sr ratios from geological samples were
only given for the MB and RCM, and these are depicted in Figure 47 as unfilled black
circles.
Strontium isotope ratios for the Afar region (see Figure 59 above for location) are
given by Betton and Civetta (1984). These values, ranging from 0.70328 to 0.70410, are
represented in Figure 47 as light-blue filled rectangles and represent the entire range of
geological compositions in Afar (from low-K tholeiites and alkali basalts) (Betton and
Civetta 1984: 61; Barberi et al. 1980). Slightly north of Afar is the Danakil Depression
where one of the most important axial volcanic chains of the Afar region, the Erta’Ale
range is located (see Figure 60 for location). Strontium ratios from this range have a
fairly limited spread of 0.7035-0.7038 (Barrat et al. 1998: 85), which fit well with the
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