1. (A) Map of Africa showing location assignments of specimens (from ref
(A) Map of Africa showing location assignments of specimens (from ref. 2) with measured F14C on ivory from the pulp cavity surface.
(A) Map of Africa showing location assignments of specimens (from ref. 2) with measured F14C on ivory from the pulp cavity surface. (B) Map of Africa showing the locations of samples of elephant hair used for calibration of F14C for elephant tissues. (C) Global map showing locations of “clean-air” sites used for calibration of the NH zones (NH1, NH2, and NH3) and SH zones (SH1–2 and SH3) for the period from 2000 to 2013; NH3 and SH3 are bounded by the northern and southern limits of the Inter-Tropical Convergence Zone (following ref. 12 for NH and SH boundaries).
Thure E. Cerling et al. PNAS doi: /pnas
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