Alfonso Benito-Calvo

Analysis of orientation patterns in Olduvai Bed I assemblages using GIS techniques: implications for site formation processes.

Mary Leakeys excavations at Olduvai Beds I and II provided an unparalleled wealth of data on the archaeology of the early Pleistocene. We have been able to obtain axial orientations of the Bed I bone and stone tools by applying GIS methods to the site plans contained in the Olduvai Volume 3 monograph (Leakey, 1971). Our analysis indicates that the Bed I assemblages show preferred orientations, probably caused by natural agents such as water disturbance. These results, based on new GIS techniques applied to paleoanthropological studies, have important implications for the understanding of the formative agents of Olduvai sites and the behavioral meaning of the bone and lithic accumulations in Bed I.

Acheulean technological behaviour in the Middle Pleistocene landscape of Mieso (East-Central Ethiopia)

The Mieso valley is a new paleoanthropological sequence located in East-Central Ethiopia. It contains Middle and Upper Pleistocene deposits with fossil and lithic assemblages in stratified deposits. This paper introduces the Middle Pleistocene archaeological sequence, attributed to the late Acheulean. Low density clusters of artefacts suggest short-term use of the landscape by Acheulean hominins. In Mieso 31, one of the excavated assemblages, refit sets indicate fragmentation of the reduction sequences and enable study of the initial stages of biface manufacture. Mieso 7, also a stratified site, is primarily characterized by a small concentration of standardized cleavers, and portrays another dimension of Acheulean technology, that related to final stages of use and discard of large cutting tools. Available radiometric dates place the Mieso Acheulean around 212 ka (thousands of years) ago, which would make this sequence among the latest evidence of the Acheulean in East Africa, in a time span when the Middle Stone Age is already documented in the region.

First GIS Analysis of Modern Stone Tools Used by Wild Chimpanzees (Pan troglodytes verus) in Bossou, Guinea, West Africa

Stone tool use by wild chimpanzees of West Africa offers a unique opportunity to explore the evolutionary roots of technology during human evolution. However, detailed analyses of chimpanzee stone artifacts are still lacking, thus precluding a comparison with the earliest archaeological record. This paper presents the first systematic study of stone tools used by wild chimpanzees to crack open nuts in Bossou (Guinea-Conakry), and applies pioneering analytical techniques to such artifacts. Automatic morphometric GIS classification enabled to create maps of use wear over the stone tools (anvils, hammers, and hammers/ anvils), which were blind tested with GIS spatial analysis of damage patterns identified visually. Our analysis shows that chimpanzee stone tool use wear can be systematized and specific damage patterns discerned, allowing to discriminate between active and passive pounders in lithic assemblages. In summary, our results demonstrate the heuristic potential of combined suites of GIS techniques for the analysis of battered artifacts, and have enabled creating a referential framework of analysis in which wild chimpanzee battered tools can for the first time be directly compared to the early archaeological record.

Atapuerca Karst and its Palaeoanthropological Sites

The Sierra de Atapuerca caves are located in the southern flank of an anticline formed by Upper Cretaceous limestones and dolomites. These caves are mainly sub-horizontal passages or water table caves recording palaeodrainage from south to north, roughly parallel to the anticline axis. In the south, groundwater recharge is mainly associated with fractures at the contact between Mesozoic carbonates and the overlying Miocene marls, while the discharge area is located to the north, in the headwaters of the Pico River. The passages are arranged in three main levels interconnected by shafts and chambers. These cave levels are perched around +90, +70 and +60 m above the Arlanzon River, coinciding with the relative heights of fluvial terraces. Episodic fluvial downcutting led to the formation of successively lower karst levels and the entrenchment of the upper conduits under vadose conditions. Accessible dry caves were used by fauna and hominids, preserving an exceptional archaeo-palaeontological record spanning from *1.2 Myr until the end of the Middle Pleistocene. The sites of Elefante, Gran Dolina, Galeria and Sima de los Huesos have provided exceptional findings for understanding the first steps of human evolution in Europe. These sites relate to the occupation of the ancient cave entrances and areas inside the cave.

Assessment of Accumulation Processes at the Middle Pleistocene Site of Ambrona (Soria, Spain). Density and Orientation Patterns in Spatial Datasets Derived from Excavations Conducted from the 1960s to the Present

The Middle Pleistocene site of Ambrona (Soria, Spain) is a major reference for European Acheulean studies. The origin of the lithic and fauna accumulations at this site was first thought to be anthropogenic, but later studies showed that it was mainly natural. The first person to conduct excavations at the Ambrona site was the Marquis of Cerralbo, in 1914; other research groups followed in more recent times (the Howell & Freeman team and the Santonja & Pérez-González team). The digs yielded a great amount of information, but until now it had never been unified. In this paper, we compile all the available published and unpublished excavation documentation from the 1960s to the present. We use these maps and sections to present our spatial study of the LSM (Lower Stratigraphic Member) at the Ambrona site, combining stratigraphic criteria with GIS density and orientation analysis. This study enabled us to define the main concentrations of the LSM, providing an initial contribution to an assessment of their accumulation processes. Most of the concentrations preserved in the ancient shore area of the site display marked orientation patterns which coincide with the direction of the main water flows into the Ambrona wetland. However, random orientation patterns were observed in the central part of the site (Alpha concentration); they may be mostly preserved without undergoing transport processes, as previous taphonomic studies also confirm.

A bunch of refits: 497D blade knapping assemblage of the Early Upper Paleolithic in Cova Gran (Northeast Iberia)

Laminar knapping is a system of methods through which a recurrent series of elongated and morphometrically repetitive blanks are obtained. The appearance of this method is associated with cognitive changes that foster different paleoanthropological discussions. This article assesses the implications of the 497D lithic assemblage of Cova Gran (Northeast Pre-Pyrenees, Iberia), whose technical principles place it within the laminar knapping sphere in which the production of blades, bladelets, and flakes are interspersed. Refitting dynamic approach allows establishing physical connections, reflecting volumetric reduction integrate sequences of sequential blanks organized by the principle of technical predetermination. Techno-typological, contextual, and chronometric attributes enable the integration of 497D within an initial phase of the Upper Paleolithic. This is an important point; although laminar knapping is widely dispersed in space and time, it marks the emergence of anatomically modern Homo sapiens associated with the Aurignacian (sensulato), a tradition marking the beginning of the Upper Paleolithic. This concept has been challenged by the proposal that the Châtelperronian laminar technocomplex was made by Homo neanderthalensis. These opposing positions fostered the Middle-Upper Paleolithic “transition” debate. Technical traits identified through refitting facilitate examination of similarities and differences between 497D and the Proto/Early Aurignacian and Châtelperronian. Observations arising from refitting in 497D influence characterization of the knapping method and its possible correlation with one of these Early Upper Paleolithic technocomplexes. These inferences broaden the goals usually associated with blade knapping, and encourage reconsideration of the classical definition of the laminar system.

Spatial and orientation patterns of experimental stone tool refits

Freehand and bipolar experimental knapping of quartzite from Olduvai Gorge in Tanzania is used to conduct spatial analysis of artefact distributions using GIS techniques, and to investigate the orientation of refit lines using circular histograms. The aim of our study is to discern patterns that can be applied to the archaeological record in two domains, namely the identification of knapping episodes and the utility of refitting line orientations in addressing post-depositional disturbance. Our spatial analysis shows that distinctive clustering patterns can be discerned according to knapping stance, handedness and flaking technique. The circular dispersion of refit lines in the horizontal distribution of bipolar assemblages is strongly patterned, indicating that anisotropy of conjoining sets is inherent to pristine hammer-and-anvil knapping episodes.