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

中文翻译：

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奥杜威峡谷取芯项目：钻探高分辨率古气候和古环境档案以限制人类进化

摘要 奥杜威峡谷取芯项目 (OGCP) 从更新世奥杜威古湖中回收的火山沉积岩芯为重建人类进化的气候和环境背景提供了高分辨率记录。通过科学钻探，从盆地沉积中心的三个钻探地点的四个岩心中回收了大约 612 m，这些岩心产生了前所未有的数据，在时间和空间上大大扩展了奥杜威记录。基于沉积学、矿物学、同位素和地球化学测量的多代理分析结果，以及对有机物和微化石的分析，以新的 40Ar/39Ar 测年、古地磁反转分析和凝灰岩指纹识别为后盾，提供详细的古生态和古环境数据，地层分辨率足以为来自露头的古人类学记录提供背景。在本期特刊中，我们介绍了核心结果的第一阶段报告，该报告建立了一个新的地层和古地理框架，可以在此基础上将古环境和古人类学数据置于背景下。岩心显示在第一层玄武岩和更古老的 Naabi Ignimbrite 下方有厚厚的湖床，是已知的奥杜威地层厚度的两倍多。地震研究表明，湖泊沉积坑中包含的沉积序列甚至可以追溯到更远的时间，可能回到~2.5 Ma，比露头暴露的最深地层古老近 500 kyr。从地层特征推断，古湖泊更深、更持久，并且在湖底池中的寿命比以前认为的要长，至少在 Masek 床之前（~0.82 Ma 之前），尽管检测到湖泊完全或几乎完全排空/干燥的频繁阶段，并且湖沉积中心有时被火山碎屑填充邻近的恩戈罗恩戈罗火山高地火山活动剧烈期间的扇形进积。此外，生物地球化学证据支持我们对湖泊历史的解释，并记录了米兰科维奇和亚米兰科维奇尺度上陆地植被、水生生物群和湖泊动态的突然转变，这可能对人类开发的古景观产生复杂的影响。