Geoarchaeology of the Soa Basin, Flores, Indonesia: New considerations on stratigraphy, chronology and palaeoenvironment

The Soa Basin, Flores contains abundant assemblages of stone tools and fossil remains, which occurred between Early Pleistocene and Middle Pleistocene. This study has used an interdisciplinary approach, integrating field and laboratory analyses, to examine geoarchaeological archives of the Soa Basin. Since the stratigraphic framework was still problematic, this study performed detailed investigations on temporal and spatial distributions of the lithological units by using lithofacies analysis and tephrostratigraphy that are combined with the 40Ar/39Ar dating technique to obtain reliable ages and establishing a new chronostratigraphical framework. The tephra records and additional chronological data demonstrate new considerations with regard to stratigraphic positions and the time of accumulation of artifacts and fossils and also permit a correlation of several important archaeological and/or palaeontological sites. The oldest Ola Kile Formation contains two pyroclastic density current (PDC) deposits, the Aesessa Ignimbrite (AEI) and Lowo Mali Ignimbrite (LMI), representing two major events of caldera-forming processes, derived from the Welas Caldera Complex (WCC) and the Keli Lambo Volcanic Complex (KLVC), respectively...