Fig. 3: Age-depth models for Namorotukunan.

obtained by correlating the depth axis, represented by the polarity pattern obtained from Namorotukunan (vertical axis) with the age axis, represented by the Geomagnetic Polarity Timescale⁹⁹ combined with additional geochronological data (horizontal axis), represented by paleomagnetic data represented by magnetic chrons, subchrons and excursions³¹ and lake phases described from the Turkana Basin^{28,47,100,101}. Two scenarios are considered: a. scenario a assumes continuous sedimentation between gravel levels C7 and lake clays L1; b., represents the second scenario which places the Burgi Unconformity at the C7/L1 lithologic boundary, as previously suggested by Kidney²¹ and Baldes et al.²⁴, providing slightly older estimates for sites NMT2 and NMT3. The scenario with the Burgi Unconformity provides two correlation options for the NZ2-RZ2 polarity interval, either with the Feni excursion (PL) or the Olduvai subchron (L). We favor the first option due to the absence of the KBS tuff in the lacustrine sediments corresponding with the NZ2 polarity zone. For lithological column and paleomagnetic polarity zone legend, see Fig. 2.