Department of Earth, Ocean and Ecological Sciences, University of Liverpool, Brownlow Street, PO Box 147, Liverpool L69 3GP, UK; The Stone Age Institute, Bloomington, IN 47407-5097, USA.
GeoZentrum Nordbayern, Friedrich-Alexander-University (FAU) Erlangen-Nürnberg, Schloßgarten 5, 91054 Erlangen, Germany.
J Hum Evol. 2018 Mar;116:27-42. doi: 10.1016/j.jhevol.2017.11.011. Epub 2018 Jan 2.
Archaeological excavations at the DK site in the eastern Olduvai Basin, Tanzania, age-bracketed between ∼1.88 Ma (Bed I Basalt) and ∼1.85 Ma (Tuff IB), record the oldest lahar inundation, modification, and preservation of a hominin "occupation" site yet identified. Our landscape approach reconstructs environments and processes at high resolution to explain the distribution and final preservation of archaeological materials at the DK site, where an early hominin (likely Homo habilis) assemblage of stone tools and bones, found close to hominin specimens OH24 and OH56, developed on an uneven heterogeneous surface that was rapidly inundated by a lahar and buried to a depth of 0.4-1.2 m (originally ∼1.0-2.4 m pre-compaction). The incoming intermediate to high viscosity mudflow selectively modified the original accumulation of "occupation debris," so that it is no longer confined to the original surface. A dispersive debris "halo" was identified within the lahar deposit: debris is densest immediately above the site, but tails off until not present >150 m laterally. Voorhies indices and metrics derived from limb bones are used to define this dispersive halo spatially and might indicate a possible second assemblage to the east that is now eroded away. Based upon our new data and prior descriptions, two possibilities for the OH24 skull are suggested: it was either entrained by the mudflow from the DK surface and floated due to lower density toward its top, or it was deposited upon the solid top surface after its consolidation. Matrix adhering to material found in association with the parietals indicates that OH56 at least was relocated by the mudflow.
在坦桑尼亚东部奥杜威峡谷（Olduvai Basin）的 DK 遗址进行的考古发掘，年代范围在约 188 万年前（玄武岩 I 层）至约 185 万年前（I 型凝灰岩）之间，记录了最早的泥石流泛滥、改造和保存的人类“居住”遗址。我们的景观方法以高分辨率重建环境和过程，以解释 DK 遗址考古材料的分布和最终保存情况，在那里发现了一个早期人类（可能是能人）的石器和骨骼组合，这些组合与 OH24 和 OH56 等人类标本非常接近，它们位于一个不平坦、异质的表面上，该表面很快被泥石流淹没，并被掩埋至 0.4-1.2 米深（原始堆积高度约为 1.0-2.4 米）。流入的中等至高粘度泥流有选择性地改变了原始“居住废弃物”的堆积，使其不再局限于原始表面。在泥石流沉积物中发现了一个弥散的碎屑“晕圈”：在遗址上方，碎屑最密集，但逐渐减弱，直到 150 米以外不再存在。从四肢骨骼中得出的 Voorhies 指数和度量指标用于空间上定义这个弥散的晕圈，并且可能表明东部存在另一个现在已经被侵蚀掉的组合。基于我们的新数据和之前的描述，提出了 OH24 头骨的两种可能性：它要么是从 DK 表面被泥石流夹带并由于顶部密度较低而漂浮，要么是在其固结后被沉积在固体顶部表面上。与顶骨相关的材料所附着的基质表明，OH56 至少是被泥石流重新安置的。
