The Olduvai Gorge Coring Project: Drilling high resolution palaeoclimatic and palaeoenvironmental archives to constrain hominin evolution

Volcano-sedimentary cores recovered from Pleistocene Palaeolake Olduvai by the Gorge Coring Project (OGCP) provide a high-resolution record for reconstructing climatic and environmental contexts of hominin evolution. Approximately 612 m were four three drill sites across basin depocentre through scientific drilling, these have yielded unprecedented data that substantially extend both temporally spatially. Results multiproxy analyses based on sedimentological, mineralogical, isotopic, geochemical measurements, along with analysis organic matter microfossils, backed up new 40Ar/39Ar dating, palaeomagnetic reversal tuff fingerprinting, detailed palaeoecological palaeoenvironmental data, stratigraphic resolution adequate to context palaeoanthropological records outcrops. In this Special Issue we present first phase reporting core results, which establishes palaeogeographic framework upon can be contextualized. The revealed thick intercalated lakebeds below Bed I Basalt even older Naabi Ignimbrite, more than doubling thickness known stratigraphy. Seismic studies suggest sedimentary sequence contained in lake's depositional sump extends further back time, perhaps ~2.5 Ma, nearly 500 kyr deepest strata exposed outcrop. From stratal characteristics, deduce palaeolake was deeper, permanent, longer-lived within lake previously thought, at least until Masek Beds (before ~0.82 Ma), although frequent phases total or emptying/drying detected, times filled volcaniclastic fan progradation during periods intense volcanic activity neighboring Ngorongoro Volcanic Highlands. Furthermore, biogeochemical evidence supports our interpretation history, documents abrupt transitions terrestrial vegetation, aquatic biota, dynamics Milankovitch sub-Milankovitch scale, potentially exerted complex influences hominin-exploited palaeolandscapes. This work revises longstanding view history transforms debate about conditions under hominins evolved Basin.