Palaeo-landscape of the Middle Pleistocene Javanese Homo erectus: Sogen Site Case Study

Ni Luh Gde Dyah Mega Hafsari1,2*, Jeroen van der Lubbe3, Tom Veldkamp4, Sofwan Noerwidi1, and Eduard Pop5

Paleoenvironmental studies offer essential insights into the ecological and developmental contexts of human evolution. Homo erectus, the oldest hominin on record to have dispersed from Africa across Europe and Asia during the Early Pleistocene, reached as far as the island of Java. Java likely represented a unique low-latitude setting, characterized by distinct palaeogeographic and palaeoclimatic conditions compared to other regions where this species occurred. Despite substantial advances in research, the palaeoenvironmental context of Homo erectus on Java remains incompletely understood, particularly for the Middle Pleistocene. The Sogen site, chronologically bracketed to the Middle Pleistocene, is located along the Solo River, approximately 8 km from the renowned Trinil site. This new site, discovered in 2019, offers a well-documented stratigraphical context with multiple sedimentary cycles culminating in palaeosols that are rich in soil carbonates and are overlain by soil carbonate lags of striped palaeosols. Furthermore, the top of the palaeosols and overlying lags are rich in fossil fauna and contain potential lithic artefacts. Therefore, stable isotope analysis (δ¹³C and δ¹⁸O) of soil carbonate nodules and herbivore tooth enamel from Sogen can provide a valuable case study for reconstructing environmental conditions for the Middle Pleistocene, including the interval of Homo erectus presence on Java. By integrating complementary isotopic archives, this study reconstructs vegetation patterns, hydroclimate variability, and landscape heterogeneity for this period.