Hard Hammer Research Articles

Ontogeny of tool use: how do toddlers use hammers?

Hammering with a hand tool appears early in life. Skillful hammering involves accommodating movements to properties of the hammer, orienting the hammer's head to the item to be struck, and maintaining stable posture during forceful action with the arm(s). We aimed to characterize development of these abilities in young children (12, 18, and 24 months old). Children struck at a peg with a hammer held in the hand or a hammer attached to a handle. Children struck more frequently with a hard hammer surface than a soft one, and more frequently (although less accurately) with handled hammers than with non-handled hammers. Developmental differences were evident in accuracy, number of strikes, and kinematic parameters, especially with the handled object. Children's ability to use objects for forceful and accurate percussion changed measurably over the second year, in tandem with improving postural stability and greater motion of the elbow.

Middle Pleistocene hominin occupation in the Danjiangkou Reservoir Region, Central China: studies of formation processes and stone technology of Maling 2A site

Danjiangkou Reservoir Region (DRR) is one of the areas where Acheulean-like stone technology (Mode 2) was reported in central and south China. It is located at the end of the upper reaches of the Hanshui River (the largest tributary of the Yangtze River). Systematic field investigations documented more than ninety Paleolithic sites along the fluvial terraces of the Hanshui and Danjiang Rivers (the latter a tributary of the upper reach of the Hanshui River). Subsequent excavations at more than 30 sites led to the discovery of a large number of Paleolithic stone artifacts in the past decade, showing that early hominins lived in the region at least by the early part of the Middle Pleistocene. However, little is known from the archaeological record about the context of the sites and their formation processes, the technological characteristics of the stone artifact assemblages, and whether they truly belong to Mode 2 technology or just to core and flake technology, and the overall hominin behavioral patterns and adaptation during the Middle to Late Pleistocene.Maling locality 2A (ML2A) is buried in the front edge of the third alluvial terrace of the Danjiang River. Archaeological excavations, undertaken at the site in 2011, recovered 1026 stone artifacts from a red clay deposit. Preliminary OSL dating and geomorphological comparisons between the terraces in the Hanshui River system suggest that the site is dated to the late Middle Pleistocene. Patterns of artifact concentration suggest that the site was buried in secondary context where the stone artifacts were transported by water from a relatively higher location nearby. The artifacts, primarily made on quartzite and quartz cobbles, include cores, whole flakes, various fragments, retouched pieces, two bifaces and a hammerstone. All flaking is by direct hard hammer without core preparation. The majority of flakes in the early stages of core reduction indicate that the cores are not extensively reduced. Choppers are the predominant core category, together with discoids, polyhedrons, and core scrapers. It should be noted that two bifacially flaked cobbles can classed as mode 2 implements. Eleven retouched pieces are recognized, and they were casually modified by direct hammer percussion. Although only two bifaces were excavated from this site, many more are recorded in the larger study area. The ML2A artifact assemblage may be considered as a Chinese variant of an Acheulean-like (Mode 2) industry. It can be deduced that Homo erectus was likely the responsible for manufacturing the stone artifacts.

The Pirro Nord site (Apricena, Fg, Southern Italy) in the context of the first European peopling: Convergences and divergences

Pirro Nord, located in Apricena, Southern Italy, represents one of the earliest records of hominin dispersal into Europe. The site is dated on a biochronological basis between 1.6 and 1.3 Ma and a significant vertebrate assemblage (Pirro Nord Faunal Unit) is associated with lithic artefacts which show many similarities with more or less contemporaneous lithic assemblages in Europe and with the African Mode 1.Since 2006, 340 artefacts have been found in the Pirro 13 fissure, and the lithic series is considered as a homogenous assemblage in terms of taphonomical, technological and raw material characteristics. Flint is the main raw material and the available and exploited flint cobbles and pebbles have different morphologies and sizes. The raw material has been collected in a secondary position near the actual location of the deposit.Two main reduction sequences have been performed by hominins in Pirro Nord: an “opportunistic” debitage, with multiple striking platforms in order to produce flakes of different morphologies including some “debordant” flakes and at least one cutting edge, and a “centripetal” or convergent debitage for the production of flakes with convergent cutting edges. The “opportunistic” approach has been adopted for the reduction of the largest flint cobbles and the polyhedral pebbles/cobbles. This method is considered as an adaptation to the raw material shape. The debitage is always made by direct percussion and hard hammer. Most of the cores are abandoned non-exhausted. In some rare cases, the use of flint pebbles of poor quality is also documented and seems to be the result of a very opportunistic and expeditious behaviour. Four flakes are retouched and are from an advanced phase of the debitage.The patterns from Pirro Nord fit well with the technological features provided by most of the European Mode 1 sites. Some peculiar features may be observed, possibly due to the main use of flint. The site with the highest similarities with Pirro Nord is Cà Belvedere di, possibly because the raw materials are ovoid flint pebbles. The lithic strategies at Pirro Nord are characterized, (1) by “opportunistic” and expedient behaviour adapted to the raw material constraints, suggested by the very short reduction sequences and by the non-exhaustion of the cores and, (2) by a series of products (pointed flakes) that appears to indicate a presumable intentionality.

Rethinking the initial Upper Paleolithic

The term Initial Upper Paleolithic (IUP) was originally proposed to describe a specific assemblage from the site of Boker Tachtit (level 4). The use of the term was subsequently extended to cover the earliest Upper Paleolithic assemblages in the Levant, characterized by forms of blade production that combines elements of Levallois method (faceted platforms, hard hammer percussion, flat-faced cores) with features more typical of Upper Paleolithic blade technologies. More recently, the term IUP has been broadened again to include any early Upper Paleolithic assemblage with Levallois-like features in methods of blade production, irrespective of location. Artifact assemblages conforming to this broadest definition of the IUP have been reported from a vast area, stretching from the Levant through Central and Eastern Europe to the Siberian Altai and Northwest China. Whereas it is indisputable that similar lithic technologies can be found in all of these areas, it is not self-evident that they represent a unified cultural phenomenon. An alternative possibility is convergence, common responses to adapting Mousterian/MSA Levallois technology to the production of blade blanks, or some combination of multiple local origins with subsequent dispersal. In this paper, we suggest that the current definition of IUP has become too broad to address such issues, and that understanding the origins of this phenomenon requires a more explicit differentiation between analogies and homologies in lithic assemblages.

Beyond the Technological Distinction between the Early and Late Mesolithic

At the beginning of the 7th millennium BC, from Tunisia to Scandinavia and the Alps to the Atlantic, the technical baggage of Mesolithic societies underwent profound changes. Flaked artifact styles, tool types, weapon hafting techniques and the volumetric principles of stone flaking were modified by more than simple adjustments to the percussion techniques commonly used, with pressure flaking and indirect percussion replacing direct hard hammer percussion. This division of the Mesolithic in Western Europe has more to do with the technology used to transform lithic raw materials than with tool typology. This observation was in fact not lost to some archaeologists of the last century, such as E. Octobon and J. G. D. Clark, who accorded less importance to punctilious arrowhead classifications than to the general structure of flaked productions, or S. K. Kozlowski who described Mesolithic Europe as being split into two successive typological “trends” (the S and K components). In this article, I first present a summary of the changes observed in the early 7th millennium, as well as the enduring features of Mesolithic material culture. I then examine possible correlations with paleo-environmental and social phenomena to show that for the moment there are no clear links to these factors. While the ultimate goal is to clearly define this vast change in civilization, it is now necessary to work at more restricted spatial and temporal scales to enhance our understanding of this fundamental phenomenon in the history of techniques on the European continent.

Newly discovered Palaeolithic artefacts from loess deposits and their ages in Lantian, central China

Eight new Palaeolithic open-air sites were identified and 770 stone artefacts were collected from 2009 to 2011 in the Lantian area of the Bahe River valley, central China. Because the famous Homo erectus fossils were unearthed at the Gongwangling and Chenjiawo localities, and more than 30 Palaeolithic open-air sites were investigated in the 1960s in this region, the catchment of Bahe River is regarded as one of the most important hominin sites from the late early Pleistocene to the middle Pleistocene. These eight newly discovered open-air sites are located at the second (n = 6), third (n = 1) or higher terraces (n = 1) of the Bahe River. The Diaozhai section on the second terrace was sampled in detail. Two samples were collected for optically stimulated luminescence dating (OSL). The OSL results suggest that a buried lithic artefact layer at the Diaozhai site spans approximately 70-30 ka. The lithic assemblage analysis suggests that the stone artefacts were made of local pebbles/cobbles such as greywacke, quartz, sandstone and igneous rocks. The main percussion techniques that were used were direct hard hammer percussion and bi-polar techniques. The lithic artefacts comprise hammer stones, cores, flakes, retouched tools and flaking debris. Acheulian-type large cutting tools (LCTs) such as hand-axes, picks and cleavers were indentified in the Lantian region as well. This is the first time Acheulian-type LCTs from the late Pleistocene have been identified in this region. This study distinguishes age gaps between Western world and East Asian Acheulian-type tools.

Coastal adaptations and the Middle Stone Age lithic assemblages from Hoedjiespunt 1 in the Western Cape, South Africa

New excavations at the Middle Stone Age (MSA) open-air site of Hoedjiespunt 1 (HDP1) on the west coast of South Africa advance our understanding of the evolution of coastal adaptations in Homo sapiens. The archaeological site of HDP1 dates to the last interglacial and consists of three phases of occupation, each containing abundant lithic artifacts, shellfish, terrestrial fauna, ostrich eggshell and pieces of ground ocher. The site provides an excellent case study to analyze human behavioral adaptations linked to early exploitation of marine resources.Here we reconstruct human activities through a detailed study of the lithic assemblages, combining analyses of the reduction sequences, artifact attributes and quartz fracturing. These methods provide insights into raw material procurement, lithic reduction sequences, site use and mobility patterns, and foster comparison with other MSA coastal sites.The main characteristics of the lithic assemblages remain constant throughout the use of the site. Quartz dominates silcrete and other raw materials by almost four to one. Knappers at HDP1 produced different forms of flakes using multiple core reduction methods. Denticulates represent the most frequent tool type. The assemblages document complete, bipolar and hard hammer reduction sequences for the locally available quartz, but highly truncated reduction sequences with many isolated end products for silcrete, a material with a minimum transport distance of 10–30km. This observation suggests that well provisioned individuals executed planned movements to the shoreline to exploit shellfish. Our excavations at HDP1 furthermore demonstrate the simultaneous occurrence of flexible raw material use, anticipated long-distance transport, systematic gathering of shellfish and use of ground ocher. The HDP1 lithic assemblages document a robust pattern of land-use that we interpret as a stable adaptation of modern humans to coastal landscapes as early as MIS 5e.

Middle to Late Pleistocene hominin occupation in the Three Gorges region, South China

The contributions of the Chinese Paleolithic record to broader ranging paleoanthropological debates – have long been difficult to decipher. The primary problem that hinders many contributions that include or focus on the Chinese record is that relatively few regions outside of the main flagship sites/basins (e.g., Zhoukoudian, Nihewan Basin, Bose Basin) have been intensively researched. Fortunately, systematic archaeological survey and excavations in the Three Gorges region, South China over the past two decades has led to the discovery of a number of important hominin fossils and Paleolithic stone artifact assemblages that have contributed to rethinking of ideas about hominin adaptations in Pleistocene China. This paper provides a detailed review of the results of recent paleoanthropological, particularly Paleolithic archaeological, research from this region.The Three Gorges region is located in the transitional zone between the upper and middle reaches of the Yangtze River (Changjiang River). Vertebrate paleontological studies indicate that the faunas from this region belong primarily to the Ailuropoda–Stegodon faunal complex, a group of taxa representative of a subtropical forest environment. Systematic field surveys identified sixteen Paleolithic sites in caves and along the fluvial terraces of the Yangtze River. Based on geomorphology, biostratigraphy, and geochronology studies, these sites were formed during the Middle to Late Pleistocene. Follow up excavations at these sites led to the discovery of a large number of Paleolithic stone artifacts, Pleistocene mammal fossils, as well as some hominin fossils. Analysis of these materials has provided the opportunity to reconstruct hominin technological and mobility patterning in a restricted spatial point. The Paleolithic technology from the Three Gorges region is essentially an Oldowan-like industry (i.e., Mode 1 core and flake technologies) comprised of casual cores, whole flakes, fragments, and chunks as well as a low percentage of retouched pieces. The utilized stone raw material is primarily high sphericity cobbles and limestone, which were locally available along the ancient river bed and surrounding terraces. Most of the artifacts are fairly large in size. All flaking is by direct hard hammer in a single direction without core preparation. Unifacial choppers are the predominant core category, with fewer bifacial choppers, sporadic discoids, polyhedrons, and bifaces. The flake types demonstrate that the first stage of core reduction is represented by a low percentage of Type III and VI flakes. Some flakes are retouched unifacially by direct hard hammer percussion on the dorsal surface of the blanks. Archaic Homo sapiens and modern H. sapiens identified from some of the cave deposits are likely the hominins responsible for the production of the stone artifacts. Implications for Oldowan-like technological patterning in South China are discussed.

Hand pressure distribution during Oldowan stone tool production

Modern humans possess a highly derived thumb that is robust and long relative to the other digits, with enhanced pollical musculature compared with extant apes. Researchers have hypothesized that this anatomy was initially selected for in early Homo in part to withstand high forces acting on the thumb during hard hammer percussion when producing stone tools. However, data are lacking on loads experienced during stone tool production and the distribution of these loads across the hand.Here we report the first quantitative data on manual normal forces (N) and pressures (kPa) acting on the hand during Oldowan stone tool production, captured at 200 Hz. Data were collected from six experienced subjects replicating Oldowan bifacial choppers. Our data do not support hypotheses asserting that the thumb experiences relatively high loads when making Oldowan stone tools. Peak normal force, pressure, impulse, and the pressure/time integral are significantly lower on the thumb than on digits 2 and/or digit 3 in every subject. Our findings call into question hypotheses linking modern human thumb robusticity specifically to load resistance during stone tool production.

Blade production ∼500 thousand years ago at Kathu Pan 1, South Africa: support for a multiple origins hypothesis for early Middle Pleistocene blade technologies

The ∼500 thousand year old stratum 4a lithic assemblage from Kathu Pan 1, Northern Cape, South Africa, is one of the earliest occurrences of blade technology and is the oldest dated assemblage attributed to the Fauresmith industry. A technological analysis of the Kathu Pan 1 stratum 4a assemblage reveals that blades were systematically removed using direct hard hammer percussion from organized blade cores that were extensively prepared via centripetal flaking. Some of these blades were retouched into points. Comparisons with published descriptions of the roughly contemporary blade assemblages from the Kapthurin Formation, Kenya and Qesem Cave, Israel demonstrate that diverse blade production strategies were employed during the earlier half of the Middle Pleistocene. The diversity best supports a scenario in which laminar technology was invented in multiple places and times.

Vein quartz in lithic traditions: an analysis based on experimental archaeology

Worldwide, vein quartz was a commonly used raw material for stone tools but this material has proved difficult for archaeologists to analyse because many quartz assemblages appear to be comprised of amorphous pieces, not easily recognised as humanly modified or forming ‘tools’. This paper discusses the analysis of the debitage – focusing on the debitage fragmentation rate, the debitage, break, and fragment types, and the quantitative analysis of the complete flakes – resulting from experimental knapping of quartz, which formed part of a project which investigated the use of quartz in Irish prehistoric lithic traditions. The results have highlighted the complexity involved in analysing quartz assemblages, and the significant differences between the debitage products of quartz and chert knapping assemblages. While bipolar knapping is generally easy to differentiate from direct percussion, it is harder to differentiate between soft and hard hammer percussion.

Raw material discernment and technological aspects of the Barranco León and Fuente Nueva 3 stone assemblages (Orce southern Spain)

Lithics from Barranco León and Fuente Nueva 3 in Orce, Spain (respectively 1.3 and 1.2 Ma according to paleomagnetic and biochronological criteria) provide information about the oldest known European Mode 1 assemblages. At these sites, both located in what were swampy areas close to the eastern shores of the Baza paleo-lake, evidence points towards competition between hominins and hyenas to access large herbivore carcasses abandoned by other carnivores. To make their tools, hominins collected rocks available nearby such as limestone and flint. Distinctive groupings of rock type with typo-technological elements are clear: flint was largely exploited for flake production whereas limestone was reserved for percussion instruments and worked cobbles. These Spanish sites do not comprise true configured tools. Knapping strategies were adapted to raw material constraints and initial block form; the hard hammer on an anvil technique was frequently used to reduce small, cube-shaped flint matrixes and some larger limestone pieces. Technical systems were mainly unidirectional recurrent, although polyhedron shaped multiplatform cores were also produced by hard hammer technique. While evidence from the Near East attests to the presence of Mode 2 producing populations as early as 1.4 Ma, such assemblages do not appear in Europe until around 0.7 Ma. Given data from the Orce assemblages, how might the earliest hominin occupations of Europe be interpreted?

A late Middle Stone Age artifact assemblage from Sibudu (KwaZulu-Natal): comparisons with the European Middle Paleolithic

It has been suggested that many behavioral innovations, said to appear during the late Middle Stone Age in sub-Saharan Africa, facilitated the expansion of anatomically modern humans from Africa and the Near East into Europe at about 50 kyr; the process eventually led to the replacement of Neanderthals by modern humans and the emergence of the Upper Paleolithic. However, assemblages in this time range are little known in South Africa. In fact, the transition from Middle to the Later Stone Age in Southern Africa is controversial. The early appearance in South Africa of many innovations, such as sophisticated knapping techniques (e.g. the use of soft hammer or indirect percussion in blade production, of composite tools, of microlithic and bladelet technologies) remains to be established through technological analysis. We present here the first results of a project designed to carry out detailed technological studies of several lithic assemblages in South Africa and France dated to the transition period. At this time we have completed the study of a post-Howiesons Poort assemblage from the rock shelter site of Sibudu. The >2 m deep stratigraphic sequence of Sibudu extends from Howiesons Poort at its base to final Middle Stone Age, directly under Iron Age layers. We have analyzed in detail layer RSP (ca. 53 kyr, 1 m above the Howiesons Poort levels) which has provided a large assemblage of several thousand stone artifacts. Compared to published MSA assemblages this industry is unusual for the very high proportions of retouched pieces (15%). The technology is not very elaborate and there is no strong standardization of the end-products. There are no flakes of predetermined shapes; retouch is used to modify irregular flakes to obtain desired edges. Knapping of flakes and blades is done by hard hammer; soft hammer is used only for retouching tools. Interestingly the older Howiesons Poort blades were produced on the same raw materials by soft hammer. Raw material (hornfels and dolerite) was procured from distances of less than 20 km. Unifacial points are the dominant type and there is strong evidence of hafting and use as spear armatures. Detailed comparisons with Middle Paleolithic assemblages of Western Europe show that the late Middle Stone Age technology in South Africa is very similar to that of the Middle Paleolithic; in fact we see no fundamental differences between the two entities, as far as lithic technology is concerned. Implications for the Out of Africa hypothesis are discussed.

Nahal Ein Gev I : A Late Upper Palaeolithic Site by the Sea of Galilee, Israel

This paper presents the results of renewed excavations at the late Upper Palaeolithic site of Nahal Ein Gev 1 on the eastern margins of the Sea of Galilee. The lithic assemblage is characterised by a chunky flake technology produced using a hard hammer. The tool repertoire is heavily dominated by burins on Clactonian truncations and notches. Other tool classes are not especially standardised, and there is a small microlithic component. The results broadly conform to those of the previous excavations and corroborate that the described assemblage is indeed representative of the site as a whole. It seems almost certain that the previously described skeletal remains are indeed integral to the site, which appears to represent a foraging camp as indicated by the broad range offaunal remains. The assemblage is placed within the framework of the later Upper Palaeolithic "Atlitian " entity. It is concluded that the techno-typolog- ical configuration of this and comparable Atlitian assemblages bear little, if any, resemblance to Levantine Aurignacian industries.

Le Paléolithique supérieur ancien en Haute-Normandie ? Etat de la recherche à travers l'étude technologique de deux sites du pays de Caux : Saint-Martin-Osmonville/la Salle et Epouville/la briqueterie Dupray (Seine-Maritime, France)

The early Upper Palaeolithic in Haute-Normandie, and more generally in northern France, is poorly known. The industries from Saint-Martin-Osmonville and Epouville are particularly interesting because the first analyses conducted during the 1970s and 1980s led to the conclusion of a possible Châtelperronian for the first site and a mixture of Aurignacian and Mousterian levels for the second one. The stratigraphic position of the industries could be an issue. In Saint-Martin-Osmonville, stratigraphic studies in the 1980s set the industry in the Nagelbeek level (22000 BP), usually sterile in this area. Recent data have shown the existence of an important hiatus covering the previous period of time, circa 70000 - 30000 BP. At Epouville, the archaeological level is systematically associated with a thin layer of "grumeleux" [gritty] alluvium which does not always rest on the same underlying deposits. More generally, this layer tops the Mesnil-Esnard stratum, which can be changeable, dilated, divided and sometimes non-existent. The industry, included in the immediately posterior alluvium, might be dated back to 45000- 40000 BP. The "série 3 " from Saint-Martin-Osmonville consists of 1134 knapped flints. Even though the patinas may vary, the assemblage remains technologically homogeneous. There are few laminar products as opposed to the number of points. The use of a softer hammer has been attested on some pieces. The study of operational schemata shows a conceptual continuity with the production of Levallois flakes and laminar production. The knapping method using unipolar sequences dominates the others. The knapping evolves progressively from a facial to a semi-rotating technique. The management of flaking surface convexities can vary greatly. There are few retouched elements, thus it is difficult to propose cultural interpretations. Unlike A. Michel's conclusions, there are no Upper Palaeolithic type tools, there are no unfinished Châtel-perronian points. This assemblage may present some Châtelperronian features including laminar products, a more rotating knapping technique, the use of a softer hammer... But some elements are missing, partly understood operational schemata (the beginning of core exploitation is missing), rare tools and few specific ones... Nevertheless, it seems that the assemblage belongs to the Middle Palaeolithic. In Epouville, the technological analysis has shown the presence of two different archaeological levels, in which two major assemblages can be found. The most important assemblage, also know as "série grise " [grey series], consists of 1034 artefacts. Its main features are a grey patina as well as variable gloss; it has been interpreted as Mousterian. The second one, also called " série vert-marron " [green-brown series], consists of 655 artefacts. Its main features are a brownish-green patina and an important gloss. This assemblage has been extremely disturbed by frost, and has been interpreted as Aurignacian. This second assemblage was the matter under discussion. The "série vert-marron " is characterized by varied production — on the one hand, we have long, regular flakes (first generation striking), and on the other we have shorter, less regular elements (second generation). These two types of production belong to the same evolutional operational schema (a few cores show successive traces of the two sequences). The first laminar knapping is done according to the semi-rotating unipolar method. The operating table is shaped by either lateral crests or a frontal crest. The use of " neo-crested " blades is frequent. The softer hammer is the sole hammer used for this operational schema. As for second generation elements, hard hammer percussion is obvious. Their knapping corresponds to a more opportunistic management of the core. The toolmaker always uses the same method (unipolar), but in a less sophisticated way and with irregular striking. There are few retouched elements, with no sign of the Aurignacian. The " série vert-marron " seems to belong to the early Upper Palaeolithic but it is difficult to be precise. The lack of technological and typological references for these times in Northern France makes it difficult for us to propose a precise interpretation of this series.

Nuts, nut cracking, and pitted stones at Gesher Benot Ya'aqov, Israel.

The Acheulian site of Gesher Benot Ya'aqov (Israel) has revealed a unique association of edible nuts with pitted hammers and anvils. Located in the Dead Sea rift, on the boundary between the Arabian and African plates, the site dates to the Early-Middle Pleistocene, oxygen isotope stage 19. In a series of strata, seven species of nuts, most of which can be cracked open only by a hard hammer, were uncovered. Five of the species are extant terrestrial nuts, and two are aquatic nuts now extinct in the Levant. In addition, the site yielded an assemblage of pitted hammers and anvils similar in pit morphology to those used by chimpanzees and contemporary hunter-gatherers. This is the first time, to our knowledge, that a site has offered both paleobotanical and lithic evidence of plant foods eaten by early hominins and technologies used for processing these foods. The evidence also sheds light on the structure of the community: ethnographic analogies suggest that mixedgender groups may have been active on the shores of paleoLake Hula.

The Refitting of Lithics from Unit 4C, Area Q2/D Excavations at Boxgrove, West Sussex, England

The refitting of lithic artifacts from Area 22/D, Boxgrove has established that the artifact concentrations were not merely the result of natural disturbances, but surviving evidence related to hominid activity. The reconstruction of flake reduction sequences, analysis of soft and hard hammer percussion modes, and Observation of the spatial distribution of lithics across the landscape have provided important information regarding the Organization of these early humans in the production of stone tools.

Flaked Stone and Social Interaction in the Casas Grandes Region, Chihuahua, Mexico

This analysis uses flaked stone artifacts to gain insight into the social and economic structure of the Casas Grandes region, northern Chihuahua, Mexico. It begins by considering the intrasite variation in flaked stone reduction at Galeana, a large site near the modern town of Galeana. The analysis of debitage and cores from Galeana indicates that the assemblage is primarily the product of hard hammer, generalized reduction of locally available materials. Differences within the assemblage indicate the presence of spatially distinct reduction areas, with initial core reduction occurring in open areas, and then continuing in room blocks. We then compare the Galeana assemblage with the flaked stone assemblage from the site of Paquimé (Casas Grandes), Chihuahua. The analysis indicates that the reduction technique employed at both sites is similar, but that the Paquimé assemblage is characterized by a greater proportion of cryptocrystaline silicates and obsidian than the Galeana assemblage. Furthermore, much of the raw material from Paquimé does not appear to be locally available. We conclude that the prehistoric inhabitants of Paquimé had greater access to cryptocrystaline silicates and obsidian acquired through trade than did the inhabitants of Galeana. This evidence indicates that the economic pattern evident at Paquimé did not extend to Galeana and supports the idea that Paquimé's economic and political influence over other Casas Grandes sites was limited beyond a 30-km radius.

Unravel The Gravel: A Study of Hunter River Mudstone and Silcrete Gravels, An Archaeological Perspective

The Hunter River is a source of mudstone and silcrete raw material utilised in the manufacture of stone implements in the Central Lowlands of the Hunter Valley. The innate differences in the physical properties of these materials provide a potential source for raw material variability in lithic assemblages. The aim of this study was to experimentally investigate this variability and identify any patterning. A limited survey of the Hunter River channel was undertaken to determine the occurrence of the materials. Samples were taken from two locations where both mudstone and silcrete occur in the gravel deposits. A controlled experiment was devised to objectively test the differences in the materials' physical properties, as expressed by their flakability and heat induced variation. To produce results in a consistent manner, and to eliminate subjective human input in the flaking process, a flaking machine was designed to simulate the human model of hard hammer percussion flaking. Also, similarly shaped rectangular cores were used. Experimental data suggests that the differences in the physical properties of the two materials can account for some of the variability in artefact form, and even assemblage variation. Heat treatment provided the Aboriginal stone worker with a lithic reduction strategy to effectively minimise the behaviour differentials of the two materials, and significantly enhance the flaking properties of one of the materials, silcrete. Experimentally heat treated mudstone and silcrete also exhibited macroscopically distinct colour change.

EMG study of hand muscle recruitment during hard hammer percussion manufacture of Oldowan tools.

The activity of 17 hand muscles was monitored by electromyography (EMG) in three subjects during hard hammer percussion manufacture of Oldowan tools. Two of the subjects were archaeologists experienced in the replication of prehistoric stone tools. Simultaneous videotapes recorded grips associated with the muscle activities. The purpose of the study was to identify the muscles most likely to have been strongly and repeatedly recruited by early hominids during stone tool-making. This information is fundamental to the identification of skeletal features that may reliably predict tool-making capabilities in early hominids. The muscles most frequently recruited at high force levels for strong precision pinch grips required to control the hammerstone and core are the intrinsic muscles of the fifth finger and the thumb/index finger regions. A productive search for skeletal evidence of habitual Oldowan tool-making behavior will therefore be in the regions of the hand stressed by these intrinsic muscles and in the joint configurations affecting the relative lengths of their moment arms.