Paleomagnetic dates of hominid remains from Yuanmou, China, and other Asian sites

Advanced dental reduction in Javanese Homo erectus

“…Currently, there are two conflicting views on the absolute dates of this stratigraphic level. While a younger chronology (Hyodo et al, 1993(Hyodo et al, , 2002 suggests ca. 1.0-0.8 Ma, an older chronology (Larick et al, 2001) proposes ca.…”

Early evidence of the genus Homo in East Asia

“…Among those studies, two representative paleomagnetic investigations of the sequence have yielded ambiguous results and implied age estimates for the hominin remains that differed by nearly 1 million years (Li et al, 1976;Hyodo et al, 2002). Li et al's (1976) results showed that the Yuanmou incisors occurred within a tiny reverse polarity magnetozone bracketed by normal polarity magnetozones.…”

“…The three magnetozones were interpreted to be the Gilsa normal event, which has an estimated age of 1.7 Ma (Worm, 1997), and those portions of the Matuyama reverse chron that border it. By contrast, a more recently reconstructed magnetostratigraphy of the Yuanmou sequence placed the incisors above the Matuyama-Brunhes boundary (Hyodo et al, 2002), which has most recently been dated at 0.78-0.79 Ma (Singer et al, 2002). In the first study by Li et al (1976), samples were not analyzed by stepwise thermal demagnetization, which is now standard practice in evaluating sediments that contain hematite as a principal remanence carrier.…”

“…In the first study by Li et al (1976), samples were not analyzed by stepwise thermal demagnetization, which is now standard practice in evaluating sediments that contain hematite as a principal remanence carrier. In the more recent work by Hyodo et al (2002), paleomagnetic analysis of the upper 88 m of M4 involved only six sampling levels, and the sampling route was about 600 m north of the hominin site (see Fig. 1 of Hyodo et al, 2002).…”

“…In the more recent work by Hyodo et al (2002), paleomagnetic analysis of the upper 88 m of M4 involved only six sampling levels, and the sampling route was about 600 m north of the hominin site (see Fig. 1 of Hyodo et al, 2002). For these reasons, the earlier studies cannot adequately resolve the age of the Yuanmou evidence of Homo; a more thorough magnetostratigraphic study directly associated with the hominin fossil site is required.…”