Revised age and stratigraphy of the classic Homo erectus-bearing succession at Trinil (Java, Indonesia)

Obtaining accurate age control for fossils found on Java (Indonesia) has been and remains challenging due to geochronologic stratigraphic uncertainties. In the 1890s, Dubois excavated numerous faunal fossils—including first of Homo erectus—in sediments exposed along Solo River at Trinil. Since then, various, often contradictory estimates have proposed Trinil site its fossils. However, fossil-bearing layers fossil assemblage inconclusive. This study constructs a chronostratigraphic framework by documenting new sections test pits, applying 40Ar/39Ar, paleomagnetic, luminescence (pIRIR290) dating methods. Our identifies two distinct, highly fossiliferous channel fills site. The stratigraphically lower Bone-Bearing Channel 1 (BBC-1) dates 830–773 ka, while 2 (BBC-2) is substantially younger with maximum 450 ± 110 ka an inferred minimum 430 50 ka. Furthermore, significantly T2 terrace deposits are present similar low elevations as BBC-1 BBC-2. results demonstrate presence Early Middle Pleistocene, potentially even late Late Pleistocene within historical excavation area, suggesting that from least three units different ages. Moreover, evidence reworking suggests material in fossil-rich strata may originate older deposits, introducing additional source temporal heterogeneity assemblage. challenges current assumption H.K. fauna –which includes erectus-is homogeneous biostratigraphic unit. this scenario might explain why skullcap collected tentatively grouped erectus Sangiran, Femur I shares affinities hominin age.