Academic Commons

Articles

Chronostratigraphy of KNM-ER 3733 and other Area 104 hominins from Koobi Fora

Lepre, Christopher J.; Kent, Dennis V.

A magnetostratigraphy for ∼60 m of Koobi Fora Formation sediment in Area 104 was derived from 46 oriented samples that produced well-resolved characteristic magnetizations from progressive thermal demagnetization. Approximately 59 m below the Morte Tuff, previously dated to ∼1.51 Ma (millions of years ago), the Olduvai-Matuyama boundary (∼1.78 Ma) was found to be at the level of marker bed A2—inconsistent with the Area 102 type section and thus contrary to fossil dating schemes that utilize temporal equivalence between A2 [104] and A2 [102]. The magnetostratigraphic data, coupled with the Morte Tuff, provide a means to interpolate new ages for marker beds A2 [104] and the White Tuff, as well as multiple Area 104 hominin fossils. Noteworthy is the new date of ∼1.63 Ma for KNM-ER 3733, which now implicates KNM-ER 2598 as the sole early African Homo erectus fossil demonstrably older than Dmanisi and Java Homo specimens. Re-dating KNM-ER 3733 creates a ∼300-kyr gap at 1.9 to 1.6 Ma in the African fossil record of H. erectus, which might be partially spanned by hand axes recently dated at ∼1.76 Ma, if the Acheulian is indeed proprietary to this species.

Geographic Areas

Files

Also Published In

Title
Journal of Human Evolution
DOI
https://doi.org/10.1016/j.jhevol.2015.06.010

More About This Work

Academic Units
Lamont-Doherty Earth Observatory
Published Here
September 22, 2015
Academic Commons provides global access to research and scholarship produced at Columbia University, Barnard College, Teachers College, Union Theological Seminary and Jewish Theological Seminary. Academic Commons is managed by the Columbia University Libraries.