A micromorphological analysis of stratigraphic integrity and site formation at Cactus Hill,an Early Paleoindian and hypothesized pre‐Clovis occupation in south‐central Virginia,USA

Twenty thin sections were studied from Cactus Hill, a ca. 20 ka stratified sand dune site in Virginia, USA, with a Clovis and hypothesized pre‐Clovis component. The high‐resolution soil micromorphology investigation focused on testing the integrity of Clovis and pre‐Clovis stratigraphy from one location where there is a high density of artifacts. Site formation processes were dominated by eolian (dune) sand formation. There was also ephemeral topsoil development and associated occupation, along with their penecontemporaneous disturbance and dispersal by scavenging animals (assumed) and localized down‐working by small invertebrate mesofauna (as evidenced by aggregates of fine phytolith‐rich humic soil and fine soil‐coated charcoal fragments). Partial erosion of these occupation soils (deflation?) was followed by successive sand burial. Post‐depositional processes affecting these sand‐buried occupations involved only small‐scale bioturbation and overprinting of clay lamellae, suggesting site stratigraphy has been stable for a long time. Soil micromorphological analysis has defined a difference between occupational units (pre‐Clovis and Clovis) and sterile units found between these units as well as above and below. In summary, according to this analysis, the site appears intact with only minor disturbances affecting the long‐term integrity of the stratigraphy. © 2008 Wiley Periodicals, Inc.     

Geoarchaeology of the Mockingbird Gap (Clovis) site,Jornada del Muerto,New Mexico

The Mockingbird Gap site is one of the largest Clovis sites in the western United States, yet it remains poorly known after it was tested in 1966–1968. Surface collecting and mapping of the site revealed a dense accumulation of Clovis lithic debris stretching along Chupadera Draw, which drains into the Jornada del Muerto basin. We conducted archaeological testing and geoarchaeological coring to assess the stratigraphic integrity of the site and gain clues to the paleoenvironmental conditions during the Clovis occupation. The 1966–1968 excavations were in stratified Holocene eolian sand and thus that assemblage was from a disturbed content. An intact Clovis occupation was found elsewhere in the site, embedded in the upper few centimeters of a well‐developed buried Bt horizon formed in eolian sand, representing the regional Clovis landscape. Coring in Chupadera Draw revealed ∼11 m of fill spanning the past ∼11,000 ¹⁴C years. The stratified deposits provide evidence of flowing and standing water on the floor of the draw during Clovis times, a likely inducement to settlement. © 2009 Wiley Periodicals, Inc.     

The evolution of Paleoindian geochronology and typology on the Great Plains

The Great Plains contain many of the best‐known Paleoindian sites in North America, and a number of these localities were key to determining the chronology of Paleoindian occupations in the years before, during, and since the development of radiocarbon and other chronometric dating methods. Initial attempts at dating were based on correlation with extinct fauna, the “geologic‐climatic” dating method, and stratigraphic relationships of artifacts within sites. By the time radiocarbon dating was developed (1950), the basic Paleoindian sequence (oldest to youngest) was: Clovis‐Folsom‐unfluted lanceolates (such as Plainview, Eden, and Scottsbluff). Initial applications of radiocarbon dating in the 1950s did little to further resolve age relationships. In the 1960s, however, largely through the efforts of C. V. Haynes, a numerical geochronology of Paleoindian occupations on the Great Plains began to emerge On the Southern Great Plains the radiocarbon‐dated artifact chronology is: Clovis (11,600–11,000 yr B.P.); Folsom and Midland (10,900–10,100 yr B.P.); Plainview, Milnesand, and Lubbock (10,200–9800 yr B.P.); Firstview (9400–8200 yr B.P.); St. Mary's Hall, Golondrina, and Texas Angostura (9200–8000 yr B.P.). The chronology for the Northern Great Plains is: Clovis (11,200–10,900 yr B.P.); Goshen (ca. 11,000 yr B.P.); Folsom (10,900–10,200 yr B.P.); Agate Basin (10,500–10,000 yr B.P.); Hell Gap (10,500–9500 yr B.P.); Alberta, Alberta‐Cody (10,200–9400 yr B.P.); Cody (Eden‐Scottsbluff) (9400–8800 yr B.P.); Angostura, Jimmy Allen, Frederick, and other parallel‐oblique types (9400–7800 yr B.P.). Fifty years after the development of radiocarbon dating, the basic typological sequence has not changed significantly except for the realization that there probably was significant temporal overlap of some point types, and that the old unilinear sequence does not account for all the known typological variation. The chronology has been continually refined with the determination of hundreds of radiocarbon ages in recent decades. © 2000 John Wiley & Sons, Inc.     

Paleochannels and Patches: A Geoarchaeological Assessment of Silcrete Sources in the Cumberland Plain,Eastern Australia

Although Aboriginal occupation dates to the Pleistocene, silcrete artifacts only begin to dominate archaeological sites found in the Cumberland Plain of western Sydney, eastern Australia, during the mid‐late Holocene. These assemblages routinely include large numbers of backed artifacts. A geoarchaeological survey of five potential silcrete source areas found that silcrete is irregularly distributed along ridgelines within gravel patches that represent paleochannel remnants. Thus, particular parts of the landscape, dictated by the geological history, were more likely to be targeted for stone procurement. The quality of silcrete differs between and within the sources due to variations in grain‐size, degree of silicification, and presence of inclusions/fractures, as well as the destructive influence of bush fires on exposed cobbles, resulting in an overall low abundance of high‐quality silcrete across the Cumberland Plain. Furthermore, a rind or chalky weathering cortex on many cobbles means that testing was required to assess the internal raw material quality. The difficulty in locating suitable raw material for artifact manufacture meant that when good silcrete sources were found, they were heavily targeted. This contextual information provides an essential backdrop in which to understand the archaeology of the Cumberland Plain and broader patterns of landscape use.     

Coastal Dynamics and Pre‐Columbian Human Occupation in Horseshoe Cove on the Northern Gulf Coast of Florida,USA

Site‐specific paleoenvironmental reconstructions are necessary to isolate environmental factors from social forces that influence shifting human practices in the coastal environment. This interdisciplinary study included the collection and analysis of marine and freshwater pond sediment cores and terrestrial sediment samples along with archaeological excavations at three directly associated pre‐Columbian sites in Horseshoe Cove on the northern Gulf Coast of Florida. This research shows a strong correlation between environmental change, the timing of initial occupation, and the morphological characteristics chosen for settlement by the pre‐Columbian residents of this area. Specific attributes sought for new settlements included elevated landforms in protected areas away from the immediate shoreline, access to fresh water from nearby spring‐fed ponds or tidal creeks, and easy access to marine resources via tidal creeks. The result of this study can be useful as a model for locating and identifying archaeological sites in similar environmental settings.     

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.     

Single‐Grain Luminescence Dating of Sediment Surrounding a Possible Late Pleistocene Artifact from the Wenas Creek Mammoth Site,Pacific Northwest,USA

Excavations at the Wenas Creek Mammoth Site yielded mammoth, bison, and two possible artifacts in a single colluvial stratum, with radiocarbon bone dates ∼17 ka. Eight infrared‐stimulated luminescence (IRSL) samples were collected to establish general ages of site strata, returning multi‐grain estimates consistent with stratigraphic integrity and the radiocarbon dates. Four additional IRSL samples were collected to estimate the depositional age of one artifact found in place. These produced a pooled total of 94 single‐grain estimates from near the artifact, 80% averaging 16.8 ± 0.9 ka, and 20% averaging 5.1 ± 0.5 ka. These results could be interpreted to demonstrate pre‐Clovis age artifact deposition consistent with the bone dates, or a mid to late Holocene intrusion into older deposits, possibly by bioturbation. The single‐grain IRSL dates do not provide proof of pre‐Clovis presence beyond reasonable doubt at this site, but do show that this technique is valuable in assessing the stratigraphic integrity needed for any such claim.     

Resolving the enigma of early coastal settlement in the Hawaiian Islands: The stratigraphic sequence of the Wainiha Beach Site in Kaua'i

Archaeological excavation has documented stratified cultural deposits at the Wainiha Beach Site in Kaua'i (Hawaiian Islands), beginning with the occupation of a residential structure dated around A.D. 1030–1400. After about A.D. 1400, the excavated area contains abundant evidence of widespread repeated temporary activities ending in the post‐Contact era (post‐A.D. 1778). The presence of an early permanent residence followed by a later period of temporary activities opposes conventional understanding of a trend from temporary to permanent occupation in similar sites in the Hawaiian Islands. The complete stratigraphic sequence is disclosed here, with reference to formation processes and depositional context of eight major strata documented in a controlled excavation 0.95 m deep. Various human activities (such as digging pits, trampling, etc.) and periodic natural high‐energy events (such as tsunami) appear to have altered the upper portions of underlying deposits. Large sections of the earliest human occupation layer were obliterated, and successive episodes of short‐lived activities created numerous inconsistencies in the stratigraphy. These results have important implications for interpreting the cultural sequence not only at Wainiha but also at other rather enigmatic beach sites in the Hawaiian Islands and elsewhere. © 2004 Wiley Periodicals, Inc.     

Luminescence dating of buried cobble surfaces from sandy beach ridges: a case study from Denmark

Here we investigate the use of optically stimulated luminescence (OSL) for dating cobbles from the body of successive beach ridges and compare cobble surface‐derived ages to standard quartz OSL ages from sand. Between four and eight cobbles and sand samples (age control) were dated with the luminescence method, taken from the modern beach and from beach ridges on the south and north extremes of a prograding spit on the westernmost coast of Lolland, Denmark. Luminescence‐depth profiles perpendicular to the surfaces of the cobbles show that the feldspar infrared signals stimulated at 50 °C were fully reset to various depths into the cobbles prior to final deposition; as a result, the equivalent doses determined from close to the surface of such cobbles can be used to calculate burial ages. Beach‐ridge burial ages given by the average of ages of individual cobbles taken from the same site are consistent, within errors, with the ages derived from the sand samples. Cobble‐ and sand‐derived ages show that the southernmost beach ridge at Albuen was formed around 2 ka ago, indicating that this sandy spit is younger than other coastal systems in Denmark. The agreement between ages derived from clasts and from standard quartz OSL in this study confirms that, even in the absence of sandy sediments, we can reliably date sites using OSL by targeting larger clasts. In addition, the record of prior light exposure contained in the shape of the cobbles’ luminescence‐depth profile removes one of the major uncertainties (i.e. the degree of signal reset prior to burial) in the luminescence dating of high latitude sites.     

The origin of the Naturaliste Plateau,SE Indian Ocean: Implications from dredged basalts

Although a 1972 dredging by USNS Eltanin from the submarine Naturaliste Plateau was reported to yield rocks of continental origin, a re‐examination of the dredge haul shows that the rock clasts are in fact altered tholeiitic basalts. They have affinities both with MOR basalts and, especially, within‐plate basalts. Petrographically they correlate most closely with the Bunbury Tholeiitic Suite on the Australian mainland to the east. The basalts are reworked cobbles in a manganiferous Quaternary slump mass, which contains a quartz‐rich, felsic, detrital mineral suite with a granite‐gneiss provenance. The basalt cobbles were part of a basal conglomerate, which covered large areas of the Plateau. It is suggested that this was laid down from nearby elevated volcanic structures formed during the inception of seafloor spreading and the separation of Greater India from Australia at about 122 Ma BP.     

Last Interglacial peopling of Siberia: the Middle Palaeolithic site Ust''-Izhul'', the upper Yenisei area

Multidisciplinary Quaternary investigations in the Minusinsk Basin in the upper Yenisei River region and other southern Siberian continental depressions have produced evidence of prehistoric peopling pre‐dating the last glacial stage (>100 ka BP). Abundant ‘pebble tools’ and bone artefacts exposed from eroded alluvia of the Yenisei River terraces indicate repeated occupation of this territory since the Middle Pleistocene. A new stage of expansion of the early human occupation habitat occurred around the last interglacial (OIS 5e) by a Middle Palaeolithic (Neanderthaloid?) population characterized by a core and flake stone industry and open‐air occupation sites. The key camp/kill‐processing site at Ust‘‐Izhul’, dated to c. 125 ka BP and documenting complex behavioural activities, is so far the most complete in situ pre‐Late Palaeolithic site found in Siberia. This unique record provides new insights into the timing and the palaeoenvironmental conditions of the Pleistocene colonization of north‐central Asia.     

Optically stimulated luminescence (OSL) dating of quartzite cobbles from the Tapada do Montinho archaeological site (east‐central Portugal)

The burial age of an alluvially deposited cobble pavement at the Tapada do Montinho archaeological site (east‐central Portugal) is investigated using optically stimulated luminescence (OSL) dating. Measurements on the cobbles (quartzite clasts) were carried out on intact slices and large aliquots (～8 mm) of quartz grains (63–300 μm), both recovered from the outer 1.5‐mm surface of the cobbles. The recycling ratio, recuperation and dose‐recovery tests show that the single‐aliquot regenerative‐dose (SAR) protocol is applicable to both rock slices and quartz grains; both have similar luminescence characteristics. The variation in the natural OSL signal with depth below the cobble surface using intact slices from two different cobbles shows that both were bleached to a depth of at least ～2 mm before deposition. A model of the variation of dose with depth fitted to data from one of the cobbles gives a burial age of ～19 ka and also predicts the dose‐depth variation at the time of deposition. Ages based on rock slices suggest that one cobble surface, and the inner parts of two other cobbles experienced a resetting event at ～45 ka, consistent with the age control. However, the surfaces of the other cobbles all record light‐exposure events in the range 26 to 14 ka, suggesting that some of the cobbles were exposed to daylight perhaps more than once in this period. Given the shallow burial depth and unexpectedly young ages of the surrounding and overlying finer‐grained sediment, it is suggested that phases of light exposure following surficial erosion are probably responsible for this underestimate. Nevertheless, it is remarkable that we can identify and quantify four events (two light exposures of different durations and two sequential burial periods) in the dose record contained within a single clast, and this suggests that the luminescence dating of rock surfaces may prove, in the future, to be at least as important as sand/silt sediment dating.     

湖北郧西黄龙洞古人类石器技术与生存行为探讨

湖北郧西黄龙洞古人类遗址自2004年发现以来已进行过3次系统发掘,出土了距今约10万年的晚期智人牙齿化石、哺乳动物化石和38件石制品。文章从类型、原料、剥片技术、加工技术等方法对石制品进行综合分析。结果表明,黄龙洞古人类选择围岩内部的石英质岩脉和洞外河流形成的河卵石进行剥片和加工石器,类型包括石锤、石核、石片、石器、断块和碎屑等,个体以中小型居多;锤击法为剥片基本方法,砸击法被少量使用;石器多为片状毛坯制作而成,刮削器是石器的主要类型,此外还有手镐、砍砸器、石锥和雕刻器等,石器为锤击法单向简单加工而成。另外,结合洞穴自然环境、动物化石埋藏及考古分析等证据,探讨了古人类于更新世晚期对黄龙洞的利用方式和生存行为。     

A log‐normal spectral analysis of inorganic grain‐size distributions from a Canadian boreal lake core: Towards refining depositional process proxy data from high latitude lakes

Better methods for interpreting grain‐size spectra will enhance current understanding of past transport–depositional processes. A high‐resolution inorganic grain‐size dataset has been measured from a freeze core extracted from ‘Alberta Lake E’ a boreal fresh water lake 40 km east of the Athabasca Oil Sands in north‐eastern Alberta, Canada. The grain‐size spectra are remarkably consistent throughout the core, exhibiting a structure comprising six persistent grain‐size distributions below ca 250 μm, plus a rare medium‐sand distribution. Automated deconvolution of the grain‐size spectra produced poor results. Constraining the modes of two of the distributions produced deconvolution solutions that were statistically excellent and consistent with the structure of each spectrum. Statistical analysis of the ‘constrained’ solutions indicates that deconvolution successfully extracted independent grain‐size populations. Conversely, the multimodal spectra generate traditional measures (for example, mean grain size) that are inconsistent combinations of different individual populations and thus are poor proxies of transport–depositional processes. Alberta Lake E is situated in a boreal wetland landscape where sediment delivery is dominated by overland flow transport during spring melt. This context means that the Alberta Lake E grain‐size spectra can be interpreted to reflect: (i) a bedload component transported during short‐duration high discharge events that reflect the intensity of the melt; and (ii) a finer suspended load component representing material whose magnitude is controlled by the volume of the spring melt. Stratigraphically, bedload and suspended load populations demonstrate different short‐wavelength and long‐wavelength cyclicity, suggesting that spring melt is likely to be driven by cyclic external forcing factors. The links between the grain‐size spectra and spring melt have potential for generating proxy records that better capture the external controls over spring melt in boreal systems and the risks associated with these energetic hydrodynamics. This is exemplified by the coarsest Alberta Lake E distributions, which indicate that more intense spring‐melt dynamics occurred in pre‐historical times.     

Last glacial ecology and geoarchaeology of the Central Trans‐Ural area: the Sosva River Upper Palaeolithic Complex,western Siberia

Chlachula, J. & Serikov, Y. B. 2010: Last glacial ecology and geoarchaeology of the Central Trans‐Ural area: the Sosva River Upper Palaeolithic Complex, western Siberia. Boreas, 10.1111/j.1502‐3885.2010.00166.x. ISSN 0300‐9483. Quaternary and geoarchaeology studies from the eastern limits of the Ural Mountains provide multiple lines of evidence of the Palaeolithic peopling of this geographically marginal and still poorly explored territory of western Siberia following the mid‐last glacial (MIS 3) warming. A complex of investigated open‐air localities in the Sosva River basin (the north‐central Trans‐Ural area) at the periphery of the western Siberian Plain, distinguished by very high concentrations of Pleistocene megafaunal remains previously regarded as ‘mammoth cemeteries’, indicate, in conjunction with the associated diagnostic ivory/bone and stone industry, open occupation sites during the Last Glacial (MIS 2). Fossil faunal remains, dominated by mammoth (98%) together with bird and fish species, indicate various methods of exploitation of the Late Pleistocene natural resources and successful behavioural adaptation to the last glacial sub‐polar tundra‐steppe environment. The taphonomy and composition of the well‐preserved skeletal remains from the main occupation sites suggest both active hunting and anthropogenic ‘scavenging’ practices. The contextual geology and the cultural and biotic multi‐proxy records from the Trans‐Ural Upper Palaeolithic Complex provide new insights into the timing and palaeoecological conditions of the Pleistocene human occupation of north‐central Asia.     

Late Holocene environmental change in southwest Greenland – fossil insect assemblages from Tasiusaq

Palaeoecological research based on insect remains from the vicinity of a Norse farm at Tasiusaq in southwest Greenland provides information on the area surrounding the farm and new information on extirpations attributed to human impact. Anthropochorous species (spread by people) from the farm faunas are lacking in the assemblages, and the natural faunas provide evidence of moderate exploitation of the landscape as a result of activities related to livestock. The gaps in the stratigraphic sequence of the site are interpreted to be the result of peat‐cutting for structural turfs or fuel, and the implications of this activity are discussed. Insect assemblages from Tasiusaq, and studies from Norse sites in Greenland, do not provide clear evidence for any distinct climatic event during the medieval period. In contrast to what happened on other islands of the North Atlantic, insects introduced to Greenland by the Norse did not find suitable natural habitats and did not survive after the demise of the farms. However, the landscape did not return entirely to its pre‐Landnám biota after the human colonizers disappeared from it. Our findings provide new evidence for the consequences of the Norse and their agricultural practices on the Greenlandic environment and additional information on the fate of insect introductions in the area during the late Holocene.     

Geological perspectives on the Monte Verde archeological site in Chile and pre-Clovis coastal migration in the Americas

Discovery of the Monte Verde archeological site in Chile overturned the previous consensus that the first Americans into the New World from Asia were the makers of Clovis projectile points, and rejuvenated the hypothesis that migration through the Americas occurred largely on portions of the Pacific continental shelf exposed by Pleistocene drawdown in eustatic sea level. The postulate of travel along a paleoshoreline now hidden underwater is an attractive means to posit pre-Clovis human movement southward from Beringia to Chile without leaving traces of migration onshore. Geologic analyses of the Pleistocene paleoenvironment at Monte Verde and of the morphology of the potential migration route along the continental shelf raise questions that have not been fully addressed. The periglacial setting of Monte Verde may call its antiquity into question and the narrowness of the Pacific continental shelf of the Americas makes it unlikely that people could travel the length of the Americas without impacting ground still onshore and no farther inland than Monte Verde itself. Geological perspectives on Monte Verde and coastal migration jointly suggest that the Clovis-first hypothesis for peopling the New World may have been abandoned prematurely.     

Unravelling the microfacies signatures of parasequences using computer-optimized similarity matrices

The microfacies of a Lower Cretaceous carbonate drillcore from Oman are characterized using optimizing matrices of Jaccard's similarity coefficients of community. Other than systems tract boundaries, there is no obvious evidence of individual parasequences in the core. However, diagnostic patterns in microfossil distribution identify environmental gradients recording changes in water depth. These gradients are used to define individual parasequences, parasequence sets, stacking patterns and key surfaces. The patterns suggest that deposition was controlled by successive fourth‐ to fifth‐order (high‐frequency) relative sea‐level cycles superimposed on an underlying third‐order relative sea‐level rise. Although the correlation of these depositional subunits to systematic changes in water depth and the rate of carbonate accumulation alone is not incontrovertible proof of such a sea‐level control, concurrent multiorder relative sea‐level cyclicity provides by far the most likely explanation. A microfacies deposited when the water depth was shallowing is characterized by a relay of microfossils with affinities that shallow upwards. Conversely, a microfacies that records a gradual increase in water depth has a relay of microfossils with affinities that deepen upwards. Microfacies characterized by an assemblage of microfossils with similar affinities record deposition when the benthic environmental conditions remained stable, either because of an equilibrium between shallow water carbonate deposition and rising sea level, or in deeper water where sediment composition was relatively insensitive to changes of water depth. Microfacies characterized by mixed affinity assemblages record syndepositional reworking. During periods of embedded multiorder sea‐level changes, individual parasequences within systems tracts are shown to record more complex environmental gradients than simply the repetition of successive shallowing‐up units as traditionally represented in carbonate sequence stratigraphic models. The microfacies of an individual parasequence may shallow up, or may record both deepening‐up and shallowing‐up depositional phases, as well as periods of sedimentation when benthic environments remained stable. Individual parasequence boundaries may be submarine or subaerial unconformities, or be conformable, as part of a predictable stratigraphic pattern related to the temporal position of an individual parasequence within the underlying third‐order cycle of relative sea‐level change. The hitherto ubiquitous use of assemblages to describe carbonate microfacies, coupled with the widespread use of the metre‐scale shallowing‐up template to identify parasequences, may have led to such complexities previously being overlooked.