Redistribution of archaeological assemblages in plowzones

Archaeological surface surveys have located open‐air sites on cropland in the Sierra de Atapuerca (Burgos, Spain). To what degree agricultural disturbances have impacted archaeological site integrity is poorly defined and may greatly affect interpretations of prehistoric land use. This paper presents the results of three experiments concerned with the effects of tillage on artifact distribution, focusing specifically on lateral and vertical artifact displacement. We demonstrate highly variable horizontal displacement of artifacts by plowing and overall downward movement of lithic materials within the soil. This results in an expansion of site boundaries and reduction of surface artifact density, yielding a biased and unrepresentative picture of past human activity. More experimental studies are needed to better define agricultural disturbances to surface archaeological assemblages. © 2008 Wiley Periodicals, Inc.     

Beyond stratigraphic noise: Unraveling the evolution of stratified assemblages in faunalturbated sites

This study explores the stratigraphic evolution of archaeological assemblages in faunalturbated sites. These sites are sometimes described as having limited archaeological value because of varying degrees of occupation mixing. It is argued here that the vertical distribution of assemblages is predictable in faunalturbated contexts. Understanding this vertical evolution may lead to a better assessment of the archaeological potential of a cultural sequence. In faunalturbated soils, the stratigraphic evolution of the assemblages is largely dictated by faunal activity. Tunneling by small animals tend to “sink” cultural remains through the deposits. Although objects sink at a relatively fast pace near the surface, the process slows down as the objects reach the bottom of the biomantle where the sediments are more compact. This process affects the shape of the artifact vertical distribution. The analysis of a multicomponent site from southern Québec is used to model how assemblages may evolve temporally in faunalturbated settings. At Station 3‐avant, the stratigraphic distribution of the cultural remains appears to evolve from an upward‐skewed distribution to a bottom‐skewed distribution through time. This evolution is interpreted to result from the fact that objects are often too large and/or heavy to be moved upward by the pedofauna. In situations in which this stage of stratigraphic evolution is not yet reached, enough information about temporal successions may be retained for the site to be useful for investigating diachronic change. This may prove invaluable in regions in which faunalturbated sequences are common. © 2006 Wiley Periodicals, Inc.     

Site formation processes at Donggutuo: a major Early Pleistocene site in the Nihewan Basin,North China

Understanding site formation processes is crucial for interpreting archaeological context patterns and hominin behaviour as these affect the preserved condition of a site and the integrity of archaeological remains. The fluvio‐lacustrine sequences in the Nihewan Basin of North China are rich sources of early Pleistocene archaeological sites, which offer an important opportunity to investigate human evolution and adapted behaviours in East Asia. Although many Palaeolithic sites have been reported from the Nihewan Basin, North China, few of them focus on site formation processes before interpreting the hominin behaviour patterns. Here, we present a site formation study of four archaeological layers (Layers 6D, 6C, 6B and 6A) in Trench 1 from the Donggutuo (namely DGT‐T1) site in the Nihewan Basin with an age of 1.1 Ma. Through the study of sedimentary contexts, spatial distributions of artefacts and fossils, intra‐assemblage category ratios, debitage size distributions, lithic abrasion, artifact orientation and planar dip, our results show that all the layers had been disturbed by low‐energy sheet wash across the lake shore setting, but to differing extents. The post‐depositional disturbance caused by water decreased from the lower to the upper layers, from Layer 6D to Layer 6A. This indicates that the archaeological remains in DGT‐T1 have not been subject to significant natural modifications and are thus suitable for studying early hominin behaviour in North China. Copyright © 2019 John Wiley & Sons, Ltd.     

Exploring Paleogeographic Conditions at Two Paleolithic Sites in Navarino,Southwest Greece,Dated by Optically Stimulated Luminescence

In this paper, we employed optically stimulated luminescence (OSL) dating of sediments from two archaeological sites located in Navarino, Messenia, southwestern Greece, to deduce a chronology for the archaeological sites. Archaeological surveys identified two Paleolithic sites on fossilized coastal dunes. Chipped stone tool assemblages were identified eroding out of paleosols developed in the dunes. The assemblage from one site lacked distinct typological features and hence it was difficult to assign to a chronological period. The lithic assemblage from the other site contained artifacts that typologically can be assigned to the Levallois‐Mousterian. Previous efforts to date the artifact‐bearing sediments at these sites were unsuccessful. Using newer OSL dating methods (i.e., the Single‐Aliquot‐Regenerated Dose protocol and thermally transferred‐OSL[TT‐OSL]), we attempted to construct a chronological framework for Late Pleistocene human activity in the southwest Peloponnese. The revised OSL chronology for the first site is 28 ± 5 ka, while a luminescence age of 8 ± 1 ka for the second site only represents a later deflation event. Within the framework of Quaternary environmental change, the location of Paleolithic sites relative to the coast would have changed during the course of the Pleistocene. As a result, Paleolithic exploitation strategies would have been strongly influenced by the changing coastal geomorphology, encouraging hominids to adapt to new distributions of resources. OSL dating of the archaeological sites allowed us to connect traces of hominid activity with climatic stadials/interstadials of the later Pleistocene derived from existing relative sea‐level curves. Ultimately, these data permitted the reconstruction of regional Late Pleistocene paleogeography. © 2012 Wiley Periodicals, Inc.     

Late Occupation of the High‐Elevation Northern Tibetan Plateau Based on Cosmogenic,Luminescence, and Radiocarbon Ages

¹⁰Be‐²⁶Al cosmogenic surface exposure, optically stimulated luminescence, and radiocarbon dates from the site of Xidatan 2 (∼4300 m above sea level [asl] in the Kunlun Pass, northern Tibetan Plateau) suggest the site was intermittently and briefly occupied approximately 9200–6400 yr B.P. This age is substantially younger than expected given the late Upper Paleolithic character of the lithic assemblage, which is dominated by microlithic and unique discoidal prepared core technologies. Comparisons between Xidatan 2 and known surface lithic assemblages in the Kekexili and Chang Tang regions of the central high Plateau show not only that the latter are technologically similar to Xidatan 2, but also that they are demonstrably connected to Xidatan 2 through utilization of the same stone raw materials, which includes a chemically distinctive obsidian. Contrary to most accounts of Tibetan Plateau colonization, our results suggest that the earliest substantial occupations on the interior Tibetan Plateau above 4000 m asl may date to the Pleistocene/Holocene transition.     

Distinguishing between naturally and culturally flaked cobbles: A test case from Alberta,Canada

Distinguishing between naturally and culturally produced, simply flaked cobbles has been a problem for proponents of a pre‐Clovis occupation in the Americas. Several sites in Alberta have been assigned a pre‐Clovis status based on the presence of simply flaked cobbles found in Late Pleistocene till deposits. Historically, these types of assemblages have been assigned a cultural status based on subjective criteria and appeals to the analyst's expertise. To determine the archaeological status of two such assemblages from Alberta (Varsity Estates and Silver Springs), they were compared to a known natural assemblage and two known cultural assemblages. Chi‐square testing was used to evaluate several lithic attributes. Only those attributes that statistically differentiated between natural and cultural assemblages were used for further analyses. All cobbles were then scored using these attributes. A point was awarded when a statistically significant attribute of human‐manufacture was present. These points were then totaled, providing an aggregate score for each cobble. These scores were plotted to determine whether the test assemblages had closer affinities with the known natural or known cultural assemblages. The results indicate that the proposed pre‐Clovis assemblages have closer affinities to known natural assemblages than to cultural assemblages. Our results suggest that these sites provide no evidence for a pre‐Clovis occupation in the Americas. © 2004 Wiley Periodicals, Inc.     

The magnetic susceptibility of cherts: Archaeological and geochemical implications of source variation

Recent exploratory studies have suggested the potential of magnetic susceptibility (MS) as a rapid and low‐cost sourcing technique for lithic archaeological materials. Most commercially available susceptibility instruments, however, do not have the sensitivity to characterize weakly susceptible cherts and silicified woods. Comparative results from nine chert, two silicified wood, a porcellanite, and four obsidian sources using a highly sensitive, calibrated, and magnetically‐shielded instrument allow exploration of MS variability within and between geological sources. Color, texture, grain size, and large inclusions of cherts and obsidians are not straightforward determinants of MS. Weathering rinds (patinas) and cortex from a variety of cherts yield reduced MS values, as does a recrystalized cobble of Rio Maior flint, indicating that magnetic mineral removal during chemical weathering and diagenesis is more prevalent than staining or other mineral penetration of cobbles. In situations of multiple overlapping MS ranges, analysis is limited to discriminating cherts with high or low MS range distributions, for example in an atypicality index. Some silicified woods, obsidians, and porcellanites possess a much greater range of intersource variability, and thus sourcing analysis is more likely to be broadly successful using the susceptibility of these materials. Unexpected results from an archaeological test using a historic lithic assemblage from Azinheira, Portugal, indicate that assemblage MS may be influenced by practices of raw material selection. Understanding variability in lithic MS has relevance for the design of most source geochemical sampling, as well as the behavioral interpretations that result from such investigations. © 2002 Wiley Periodicals, Inc.     

Desert Pavement—the most ancient surface or a more recent development?

Desert pavement comprises a surficial layer of gravel clasts and cobbles underlain by dust and silt that mantles mature alluvial surfaces in arid regions around the world. Once thought to originate from either deflation or expansion and contraction of wet desert soils, desert pavement is now known to form in place from the aeolian accumulation of dust beneath a surface layer of gravel. Desert pavement affects the type and distribution of desert plants on arid land surfaces, as well as inhibits the activities of small burrowing animals. Considerable debate surrounds the age of pavement surfaces and how well they survive changes in climatic conditions. Some researchers maintain that most desert pavements developed during the Holocene, whereas others indicate that some of the oldest surface soils on the planet are desert pavements in the Middle East.     

The accumulation of Stone Age lithic artifacts in rock fragment mulches in northern Ethiopia

Lithic artifacts buried in the soil profile may be transported to the surface during tillage‐induced kinetic sieving, differential erosion, or swell–shrink cycles of clays and become part of a rock fragment mulch. Archaeologically, these manifestations are recognized as surface scatters. Although artifacts at the soil surface are difficult to relate to the local stratigraphic context, surface assemblages may provide information on lithic industries and the archaeological significance of sparsely explored regions. Through in situ investigation of surface material in 60 1 × 1 m² plots in the Tembien district in the northern Ethiopian highlands, we show that rock fragment mulches can contain a significant number of lithic artifacts and we provide evidence for mid‐Pleistocene occupation of a site. Considering that severe rill and gully erosion may be a threat to the archaeological heritage and that well‐dated African Middle Stone Age sites are rare, we conclude that the region deserves more attention for archaeological research. © 2009 Wiley Periodicals, Inc.     

Acheulean artifact accumulation and early hominin land use,Garden Route Casino Road,Pinnacle Point,South Africa

An Early Stone Age Acheulean lithic assemblage collected along a 1.5‐km transect at the Garden Route Casino near Pinnacle Point, Mossel Bay, South Africa, was examined in order to assess the relative degree to which assemblage variability is impacted by post‐occupational processes and/or terrain. It was found that post‐occupational variables do vary across the study area, and they affect the positions of artifacts to different degrees. Terrain structure was determined to have minimal effect on artifact movement. Three analysis sections were identified as having artifacts that were likely close to their original positions and compositions. Future interpretations of differential land use can now be tempered with considerations of the post‐occupational processes that formed the recovered assemblage. © 2009 Wiley Periodicals, Inc.     

Distinguishing bioturbation and trampling using pottery sherd measures,Tell Fendi,Jordan

In the Levant, the blind mole‐rat (Spalax ehrenbergi) is responsible for much disturbance at archaeological sites, but its potential destructiveness is often ignored when cultural remains are interpreted. The effects of mole‐rat burrowing on artifact distributions were evaluated through a study of mole‐hill contents and by doing a vertical particle‐size analysis of ceramic materials drawn from Tell Fendi, a Late Chalcolithic (6600–5500 B.P.) site in the Jordan Valley. While the general effects of animal burrowing are predictable to some degree, stratigraphic units affected by burrowing may not be immediately obvious to the archaeologist. The problem of identification is compounded because other disturbance processes produce similar effects. This study proposes a method for identifying bioturbation layers and for distinguishing these layers from both trampled surfaces and in situ contexts by means of pottery sherd measures. © 2000 John Wiley & Sons, Inc.     

青海湖盆地史前狩猎采集人群的石料利用策略研究

史前人类向青藏高原扩散的过程和适应高海拔缺氧环境的机制是多学科关注的热点科学问题.青海湖盆地是青藏高原旧石器-中石器时代遗址分布最为丰富的区域,对这些遗址出土的石制品原料的分析有助于深入理解青藏高原史前狩猎采集人群的石料开发策略、人群迁徙和交流联系.青海湖盆地151遗址出土的928件石制品的石料研究分析显示,处于末次冰消期的下文化层的石制品以近源的石英和石英岩为主要原料,而处于全新世早中期的上文化层在同类型近源石料仍占主体地位的情况下,开始出现较高比例和多样化的优质硅质石料,并且主要用于生产细石器.野外调查和查阅地质资料均未发现青海湖盆地内有151遗址中出现的同类型优质硅质石料产出,推测其来自远距离搬运.青海湖盆地内其他8个末次冰消期至全新世中期遗址的3269件石制品石料分析结果显示,与151遗址同类型的远源优质硅质石料在全新世早期开始在盆地内的遗址中出现.这一结果表明青海湖盆地末次冰消期古人类活动强度和范围有限,全新世早中期古人类受到全新世大暖期气候变好和周边地区农业人群兴起挤压活动空间的双重影响,在高原上的活动范围和强度大大增加,伴随着开始有意识地开发优质石料,较频繁地进行远距离迁移和人群交流.远源优质硅质石料的产地可能位于北祁连山区和青藏高原上的陆相火山岩区,需要未来更深入的研究揭示.该研究为深入理解青藏高原古人类的高海拔环境适应策略和移动模式提供了重要材料,为理解史前人类向高原扩散的机制提供了重要信息.     

How Do Surficial Lithic Assemblages Weather in Arid Environments? A Case Study from the Atacama Desert,Northern Chile

Archaeological sites composed only of surficial lithics are widespread in arid environments. Numerical dating of such sites is challenging, however, and even establishing a relative chronology can be daunting. One potentially helpful method for assigning relative chronologies is to use lithic weathering, on the assumption that the most weathered artifacts are also the oldest. Yet, few studies have systematically assessed how local environmental processes affect weathering of surficial lithics. Using macroscopic analyses, we compared the weathering of surficial lithic assemblages from seven mid‐to‐late Holocene archaeological sites sampled from four different microenvironments in the Atacama Desert of northern Chile. Changes in polish, texture, shine, and color were used to establish significant differences in weathering between two kinds of locations: interfluves and canyon sites. Lithics from interfluve sites were moderately to highly weathered by wind and possessed a dark coating, whereas canyon lithics were mildly weathered despite greater exposure to moisture, often lacked indications of eolian abrasion, and lacked dark coatings. Our results show that lithic weathering can be used as a proxy for relative age, but only after considering local environmental factors. The power of such chronologies can be improved by combining archaeological, paleoenvironmental, geomorphological, and taphonomic data.     

The Paleoenvironment and Lithic Taphonomy of Shi’Bat Dihya 1, a Middle Paleolithic Site in Wadi Surdud,Yemen

The Shi'bat Dihya 1 site in western Yemen, dated by optically stimulated luminescence to 55 ka, provides insight into the Middle Paleolithic peopling of the Arabian Peninsula. The archaeological layer is interstratified within thick, sandy silt floodplain deposits filling a piedmont basin. Luminescence dates, lack of soil development, and gypsum precipitation indicate a high accretion rate of the floodplain during Marine Isotope Stage 3, in connection with a (semi)‐arid environment. Rapid overbank sedimentation was likely a result of the remobilization of loess material deposited on the Yemeni Great Escarpment at the periphery of the adjacent Tihama coastal sand desert or of other sources. Fabric and size analyses of the lithic artifacts, together with spatial projections, indicate site modifications by floods. Primary modifications include (1) selective accumulation of medium‐sized lithic pieces as a result of hydraulic sorting, (2) bimodal orientation of artifacts, and (3) ripple‐like arrangement of lithics and bone/tooth fragments. The overrepresentation of teeth may also be a consequence of sorting. Although floods have distorted the original site patterning, long‐distance transport of artifacts by water can be excluded, as indicated by relatively high refitting rate, close proximity of artifacts derived from the same block of raw material, and lack of abrasion of the pieces. Therefore, the site is considered “geologically” in situ because its remobilization by water occurred shortly after human abandonment. This study also stresses that the effective preservation of a site cannot be assessed without careful taphonomic study, even in a potentially favorable depositional context such as silty alluvium.     

The surface archaeological record in arid Australia: Geomorphic controls on preservation,exposure, and visibility

The conventional approach to assessing the archaeological record in most parts of the world involves a combination of excavation of stratified deposits and extensive survey of surface deposits. Although widely applied in Australia, in both research‐based and management archaeology, the method does not conform well to the nature of the surface archaeological record here. Over much of semi‐arid and arid Australia, archaeological “sites” are, in fact, accretion phenomena that are not easily interpreted as the outcome of short‐term behavioral events. Using results from twelve years of geoarchaeological research in western New South Wales, we demonstrate that there is considerable variability in landsurface age, and hence the “availability” of archaeological surfaces, over relatively short distances. Therefore, it cannot be assumed that stone artifact deposits, for example, that appear to be similar in character are of similar age. Data are also presented that demonstrate that the presence of artifacts on the surface, their apparent absence in sediments buried beneath the surface, and the apparent recent ubiquity of the archaeological record are all a function of geomorphic processes that, at the same time, expose some artifact deposits at the surface and erode and bury others amid large volumes of sediment. Interpreting the surface artifact record within a spatial and temporal geomorphic framework is crucial to understanding the past human behavior that the artifact deposits represent. © 2009 Wiley Periodicals, Inc.     

Comparison of sedimentation and occupation histories inside and outside rock shelters,Keep‐River region,northwestern Australia

This paper compares archaeological evidence of Aboriginal occupation inside rock shelters and outside in adjacent sand sheets, focusing on two locations in the Keep‐River region, northwestern Australia. Luminescence and radiocarbon dating reveal that occupation sequences inside rock shelters are generally younger ( < 10,000 yr B.P.) than outside ( < 18,000 yr B.P.). Differences in occupation chronology and artifact assemblages inside and outside rock shelters result from depositional and postdepositional processes and shifts in site function. An increase in regional sedimentation rate from 10 cm/ka ^{− 1} in the Pleistocene to 20 cm/ka ^{− 1} in the Holocene may account for late buildup of sediments within rock shelters, increased artifact accumulation, and reduced postdepositional disturbance in some settings. More intense use of rock shelters in the Late Holocene is indicated from a change in hunting technology and greater production of rock art. The results indicate that some cultural interpretations might be flawed unless archaeological evidence from rock‐shelter and open‐site excavations is integrated. © 2006 Wiley Periodicals, Inc.     

Paleoeskimo site taphonomy: An assessment of the integrity of the Tayara site,Qikirtaq Island,Nunavik, Canada

A detailed taphonomic study was undertaken at the Tayara site in order to determine the impact of natural processes such as surface water flow on spatial patterning and site formation. The study focused on Paleoeskimo level II, which contains many lithics and significant faunal remains. Level II integrity was assessed through spatial analysis and by examining the size distribution of lithic artifacts and bone orientation. Experimental knapping aimed at replicating Paleoeskimo lithic technology was used to assess the possible size sorting of lithics. The study indicates that artifact burial by water‐laid sediments did not result in a selective impoverishment in small‐sized lithics. Statistically significant lithic concentrations and associations suggest that spatial distribution was not significantly modified by site formation processes. However, slight post‐depositional changes were presumably induced by water flows in the form of statistically significant horizontal bone reorientations. These occurred when gently flowing water inundated bone accumulations without inducing significant washing or sorting of smaller lithic debris. The spatial integrity evaluation of the level II assemblage reveals a low degree of spatial disturbance and disorganization of the material (i.e., limited entropy), which is likely related to low‐energy hydraulic forces and rapid burial soon after Paleoeskimo occupation. The grouping and deposition of much of the occupation debris is likely the result of Paleoeskimo activities (e.g., knapping and butchering), and the lithics and fauna specimens are probably at or very near their original location. These results show the behavioral significance of the grouping and deposition of debris in Tayara's level II. © 2009 Wiley Periodicals, Inc.     

The effects of surface weathering on the geochemical analysis of archaeological lithic samples using non‐destructive polarized energy dispersive XRF

The purpose of this paper is to show the effects of lithic artifact surface weathering on whole rock non‐destructive polarized energy dispersive X‐ray fluorescence (P‐ED‐XRF) major and trace element determinations. Chemical results for a weathered and subsequently mechanically ground subset of New Hampshire Ossipee archaeological flakes, cataloged as hornfels, show that both groups of elements are variably affected by weathering. A graphic approach is developed and proposed to highlight the role and importance of immobile elements. A case is made and an analytical method is proposed for the routine use of P‐ED‐XRF spectrometers to determine the chemical makeup of lithic artifacts and therefore provide a data set compatible with existing geochemical databases and literature. The use of specific variation diagrams is adopted to portray the weathering trend. Internationally approved geochemical rock type diagrams are used to correct the rock type previously assigned to Ossipee artifacts and in turn narrow down potential quarry sources. © 2011 Wiley Periodicals, Inc.     

Mineralogy of arc-derived sediment: siliciclastic sediment on the insular shelf of Puerto Rico

Siliciclastic sediments on the insular shelf of Puerto Rico are derived from a volcanic arc. The sands are feldspatholithic and subquartzose. They confirm predictions about sandstones of arc derivation in the following ways. The quartz content is low, usually less than 25 %. Feldspar is more abundant than quartz, but less so than lithic fragments. If mud rip-up clasts are excluded from the lithic suite, the ratio V/L (volcanic lithic grains to total unstable lithic grains) assumes values near 0.75. Most of the volcanic lithic grains have textures suggesting intermediate volcanics as source rocks. Ratios of plagioclase to total feldspar are high. Values of the parameter C/Q (stable lithic fragments to total lithic grains) are higher than expected for sandstones of volcanic provenance. Four compositionally and areally distinct assemblages of clay minerals are recognized. Clay suites characterized by major concentrations of both halloysite and smectite are found off the north-west coast. Sediments off the north-central and north-east coasts contain major concentrations of halloysite and lesser amounts of smectite, illite and chlorite. Major concentrations of kaolinite are present off the south-east coast. An assemblage of poorly crystallized smectite with lesser amounts of illite and chlorite occurs off the south-west and south-central coasts. Variation in the mineralogic composition of clays around the perimeter of the island reflects changes in the intensity of chemical weathering and the type of rock exposed in the immediate source area and, in instances, either early diagenetic alteration or, more likely, sorting within the clay fraction by currents on the shelf.     

柴北缘西段古近纪物源体系分析

沉积区物源分析对研究造山带构造演化、盆地沉积过程及划分油气区带等方面具有重要的意义。为了查明柴达木盆地北缘构造带古近纪物源方向,通过对古近系碎屑岩的碎屑组成、岩屑成分、重矿物组合特征和ZTR指数的研究,并结合前人的研究成果,初步确定古近纪柴北缘西段发育五大主力物源区:(1)牛东物源主要来自阿尔金山东段,重矿物组合以稳定且含量较高的电气石区别于邻区,碎屑组分中以石英和含量较高的长石为特征,岩屑中含有少量的碳酸盐岩岩屑;(2)冷北物源主要来自小赛什腾山方向,重矿物组合中榍石和赤铁矿的含量明显偏高,碎屑组分中以高岩屑为特征;(3)赛西物源主要来自赛什腾山西段,电气石和角闪石含量较高,碎屑组分较为均一,母岩以变质岩和火成岩为主,含少量碳酸盐岩岩屑;(4)赛东物源主要来自赛什腾山东段,其白钛矿含量明显高于邻区,碎屑组分以较高含量的石英和长石为主,岩屑类型主要为变质岩、火成岩和沉积岩岩屑;(5)九龙山物源主要来自九龙山和绿梁山地区,石榴石含量高且稳定,碎屑组分较为均一,母岩以变质岩和火成岩为主,含少量的非碳酸盐岩类沉积岩岩屑。