古人类遗址湖北郧西黄龙洞的铀系年代

湖北郧西黄龙洞为近年来发现的晚期智人遗址。本文报道该地点具明确层位意义的洞穴次生碳酸盐岩和骨化石样铀系测年的结果。含文化堆积下伏一局部钙板的年代为约100ka BP, 其中部偏上一局部钙板为约77ka BP, 表层钙板形成于27—57ka BP间。人类化石和石制品出土于文化堆积的底部, 其年代应在57—100ka BP, 并很可能在77—100ka BP间。与人牙化石同层的四枚犀牛牙化石在35—72ka BP间, 与基于次生碳酸盐岩的年代框架没有冲突。本文结果为中国现代人类的早期出现和距今40—100ka BP间有人类活动提供了有力证据。     

26Al/10Be Burial Dating of Xujiayao-Houjiayao Site in Nihewan Basin,Northern China

The Xujiayao-Houjiayao site in Nihewan Basin is among the most important Paleolithic sites in China for having provided a rich collection of hominin and mammalian fossils and lithic artifacts. Based on biostratigraphical correlation and exploratory results from a variety of dating methods, the site has been widely accepted as early Upper Pleistocene in time. However, more recent paleomagnetic analyses assigned a much older age of ∼500 ka (thousand years). This paper reports the application of ²⁶Al/¹⁰Be burial dating as an independent check. Two quartz samples from a lower cultural horizon give a weighted mean age of 0.24 ± 0.05 Ma (million years, 1σ). The site is thus younger than 340 ka at 95% confidence, which is at variance with the previous paleomagnetic results. On the other hand, our result suggests an age of older than 140 ka for the site’s lower cultural deposits, which is consistent with recent post-infrared infrared stimulated luminescence (pIR-IRSL) dating at 160–220 ka.     

Datation d’enfouissement par 26Al/10Be et son application préliminaire à des sites du Paléolithique Inférieur en Chine et en France

The radionuclides ²⁶Al and ¹⁰Be in situ produced in quartz near the ground surface by secondary cosmic rays can be used for dating the sediment burial. This paper introduces the principles, preconditions and limitations of the recently established dating method. In China its first trial application is to the site of Peking man. The weighted mean of six significant results of samples from layers 7–10 is 770 ± 80 ka. This date provides strong support to an earlier and longer human presence at the site than once estimated. This method has also been applied for the first time to two Lower Paleolithic sites in the Cher Valley, central France, Lunery “la Terre-des-Sablons” and Brinay “la Noira”. The preliminary results attribute ages of 750 ± 240 and 730 ± 210 ka to the two sites, largely consistent with the previous age estimates based on geological and geomorphological studies and on ESR dating. With its well-founded basis in physics, its independence from other dating methods and its timescale filling a “blank period” in radioisotopic dating, the ²⁶Al/¹⁰Be burial dating will be widely applied and contribute substantially to the establishment of a reliable timescale for the earliest human occurrence and evolution in China and in Europe.     

Position chronologique des sites de l’Homme moderne en Chine d’après la datation U-Th

The origin and evolution of modern Homo sapiens has been the subject of an intensive debate between exponents of two competing hypotheses, multiregional origins and “recent out of Africa”. This paper presents a synthesis of the chronological studies on seven hominid sites in China based on the U-series dating, five of them of intercalated speleothem calcites and other two of fossil materials. The results show that modern humans were present in China about 100 ka ago, much earlier than previously estimated, and that the so-called “temporal gap” of human presence in China between 40 and 100 ka is most probably nothing but an artifact caused by systematic errors of the dating methods. Further multidisciplinary studies on hominid sites in China may provide important evidence for resolving the hotly debated issues concerning the origin of modern humans.     

Luminescence chronology of cave sediments at the Atapuerca paleoanthropological site, Spain

Ascertaining the timing of the peopling of Europe, after the first out-of-Africa demographic expansion at the end of the Pliocene, is of great interest to paleoanthropologists. One of the earliest direct evidences for fossil hominins in western Europe comes from an infilled karstic cave site called Gran Dolina at Atapuerca, in a stratum approximately 1.5m below the Brunhes-Matuyama (B-M) geomagnetic boundary (780ka) within lithostratigraphic unit TD6. However, most of the meters of fossil- and tool-bearing strata at Gran Dolina have been difficult to date. Therefore, we applied both thermoluminescence (TL) and infrared-stimulated-luminescence (IRSL) multi-aliquot dating methods to fine-silt fractions from sediment samples within Gran Dolina and the nearby Galería cave site. We also applied these methods to samples from the present-day surface soils on the surrounding limestone hill slopes to test the luminescence-clock-zeroing-by-daylight assumption. Within the uppermost 4m of the cave deposits at Gran Dolina, TL and paired TL and IRSL ages range stratigraphically from 198+/-19ka to 244+/-26ka. Throughout Gran Dolina, all luminescence results are stratigraphically self-consistent and, excepting results from two stratigraphic units, are consistent with prior ESR-U-series ages from progressively deeper strata. Thermoluminescence ages culminate at 960+/-120ka approximately 1m below the 780ka B-M boundary. At Galería, with one exception, TL and IRSL ages range stratigraphically downward from 185+/-26ka to 503+/-95ka at the base of the lowermost surface-inwash facies. These results indicate that TL and (sometimes) IRSL are useful dating tools for karstic inwash sediments older than ca. 100ka, and that a more accurate chronostratigraphic correlation is now possible among the main Atapuerca sites (Gran Dolina, Galería, Sima de los Huesos). Furthermore, the oldest TL age of ca. 960ka from Gran Dolina, consistent with biostratigraphic and paleomagnetic evidence, implies a probable numeric age of 900-950ka for the oldest hominin remains ( approximately 0.8m below the TL sample). This age window suggests a correspondence to Marine Isotope Stage (MIS) 25, a relatively warm and humid interglaciation.     

Southern Africa and modern human origins.

This paper argues that southern Africa was a remote part of the Old World in the late Pleistocene (125-10 ka ago). Because of this isolated position there was continuity without significant replacement in the resident population. Isolation and the relatively recent spread of agriculture to the region has allowed a section of this population to survive into the present. They are the Bushmen (San). Studies of geographic patterning in conventional genetic markers and mitochondrial DNA indicate that the Bushman clade has a long evolutionary history in southern Africa. Estimates of more than 100 ka for the continued presence of this population in the region are supported in archaeological investigations of sites with long sequences such as Klasies River main site and Border Cave. Human remains dating to the earlier part of the late Pleistocene have been recovered from these sites and the samples form a morphological series with the Klasies River remains possibly 20 ka older than those from Border Cave. There is no fossil record for the later Pleistocene, however, at a period when selection for a gracile morphology may have been pronounced. The cultural associations in the earlier late Pleistocene are with the Middle Stone Age. Expressions of cultural 'style' and the occurrence of similar artefact design types in the Middle and Later Stone Ages can be interpreted with reference to the ethnographic present. Temporal continuity can be shown in the geographical distribution of stylistic markers and this suggests participation in a shared cognitive system.(ABSTRACT TRUNCATED AT 250 WORDS)     

广西柳江土博甘前洞的铀系年代

本文报道晚期智人化石地点广西柳江博甘前洞新生碳酸盐岩和骨化石样的铀系测年结果。该地点表层钙板在约94Ka前开始形成,含化石粘土堆积叠压的钙板年代为约20ka,人牙化石应位于二者之间。二个动物化石样的二种铀系法年代范围为85－139ka,表明该地点与含化石堆积与表层钙板间无地层倒序现象,支持人牙化石大于100ka的结论。邻近的柳江晚期智人化石地点和柳州白莲洞人类遗址铀系测年的结果与本文一致。具现代解剖特征智人在中国南方出现的时间,很可能不晚于西非和非洲。在现代人类起源方面,中国不应是远离中心、滞后和被取代的地区。     

Mass spectrometric U-series dating of Huanglong Cave in Hubei Province,central China: Evidence for early presence of modern humans in eastern Asia

Most researchers believe that anatomically modern humans (AMH) first appeared in Africa 160-190 ka ago, and would not have reached eastern Asia until ∼50 ka ago. However, the credibility of these scenarios might have been compromised by a largely inaccurate and compressed chronological framework previously established for hominin fossils found in China. Recently there has been a growing body of evidence indicating the possible presence of AMH in eastern Asia ca. 100 ka ago or even earlier. Here we report high-precision mass spectrometric U-series dating of intercalated flowstone samples from Huanglong Cave, a recently discovered Late Pleistocene hominin site in northern Hubei Province, central China. Systematic excavations there have led to the in situ discovery of seven hominin teeth and dozens of stone and bone artifacts. The U-series dates on localized thin flowstone formations bracket the hominin specimens between 81 and 101 ka, currently the most narrow time span for all AMH beyond 45 ka in China, if the assignment of the hominin teeth to modern Homo sapiens holds. Alternatively this study provides further evidence for the early presence of an AMH morphology in China, through either independent evolution of local archaic populations or their assimilation with incoming AMH. Along with recent dating results for hominin samples from Homo erectus to AMH, a new extended and continuous timeline for Chinese hominin fossils is taking shape, which warrants a reconstruction of human evolution, especially the origins of modern humans in eastern Asia.     

Uranium-series dating and the origin of modern man.

Uranium-series dating is based on measurement of the radioactivity of short-lived daughter isotopes of uranium formed in samples which initially contained only the parent uranium. Materials suitable for U-series dating are found in many prehistoric archaeological sites, and include stalagmitic layers (flowstones), and spring-deposited travertines. Some marls and calcretes are also datable using isochron methods, whereas dates on molluscan shells, bones and teeth are less reliable. Ages obtained using alpha counting to determine isotope ratios have errors greater than 5%, and can range from 1 to 350 ka. Mass spectrometric methods slightly increase the range (0.1-500 ka) but greatly decrease the error to less than 1%, making this the optimal method for high-precision dating of the origin of modern man.     

Thermoluminescence dating tests of Pleistocene sediments from uplifted marine shorelines along the southwest coastline of the Calabrian Peninsula (southern Italy)

This paper presents TL age estimates of Pleistocene raised marine terraces from southern Calabria (southern Italy). It focuses on the dating of last interglacial shallow-marine sand deposits, including several Tyrrhenian key reference deposits whose stratigraphic assignment is based on biostratigraphic evidence (presence of a Strombus bubonius fauna) and geochronometric data (amino-acid data calibrated with U/Th dates on coral). The TL age estimates are obtained on alkali feldspar coarse grains using their blue TL emission. They are in good agreement with the IR-OSL age estimates obtained on the same feldspar samples. Our feldspar TL method is tested on two Tyrrhenian key reference sites, Ravagnese and Bovetto, in the Reggio di Calabria area. Their measured TL age estimates (97 ± 11 ka and 100 ± 10 ka) are lower than their estimated geological age (i.e. Oxygen Isotope Substage 5e). The correction for long-term fading suggested by Mejdahl (1988), is tested on these two samples using a lifetime of 446 ka as estimated from both Calabrian and Miocene sand collected within the same area. This correction would yield preliminary TL ages (116 ± 13 ka and 116 ± 12 ka) that are in better agreement with the expected geological age. The application of our TL method to paleoshorelines lying below the Tyrrhenian reference shoreline of Ravagnese-Bovetto, yields stratigraphically consistent TL age estimates. The TL method is also applied to two supposedly pre-last interglacial paleoshorelines which are geomorphologically older than the Tyrrhenian reference shorelines. They remain however chronologically undifferentiated, both by the TL and the amino-acid methods. Finally, the preliminary feldspar TL results obtained on the Miocene and the Calabrian sand deposits (> 1 Ma), suggest that our feldspar TL method is limited, in the SW Calabrian area, to about 200 ka.     

Models and realities in modern human origins: the African fossil evidence.

The recent application of such chronometric techniques as electron spin resonance (ESR), thermoluminescence (TL), and uranium series dating has had a significant impact on perceptions of modern human origins. Claims for the presence of anatomically modern humans in Africa prior to 100 ka and for the transition leading to modern Africans at an even earlier date have been made, partly based on results of these techniques. However, a careful examination of the pertinent record shows that these claims are not unequivocally supported by the available fossil and chronological evidence.     

The Pech-de-l'Azé I Neandertal child: ESR, uranium-series, and AMS 14C dating of its MTA type B context

The Pech-de-l'Azé I skull and mandible are included in the juvenile Neandertal remains from Europe. However, some preserved features in the cranial skeleton seem to distinguish the specimen from other Neandertal children. Unfortunately, the stratigraphic position and dating of this child has never been clear. Our recent work on unpublished archives show that the Pech-de-l'Azé I Neandertal child was discovered at the bottom of layer 6, attributed to the Mousterian of Acheulean tradition type B. These skull and mandible are the first diagnostic human remains (aside from an isolated tooth) attributed to the Mousterian of Acheulian tradition (MTA) type B. Consequently, we confirm that Neandertals were the makers of this Mousterian industry, which is characterized by unusual high frequencies of Upper Paleolithic type tools, elongated blanks and blades. We were able to date the context of the hominid remains by dating layer 6 and the layers above and beneath it using ESR, coupled ESR/(230)Th/(234)U (coupled ESR/U-series), and AMS (14)C. Coupled ESR/U-series results on 16 mammalian teeth constrain the age of the uppermost layer 7 to 41-58ka, and layer 6 to 37-51ka. The wide spread in each age estimate results mainly from uncertainties in the gamma-dose rate. These ages are concordant with AMS (14)C ages of two bones coming from the top of layer 6, which provide dates of about 41.7-43.6ka cal BP. A combination of stratigraphic arguments and dating results for layers 6 and 7 show that the Neandertal child cannot be older than 51ka or younger than 41ka. The lowermost layer 4 is shown to be older than 43ka by the principle of superposition and ESR dating in the immediately overlying layer 5. This study shows that the MTA type B had been manufactured by Neandertals before the arrival of anatomically modern humans in the local region. Additionally, by providing a firm chronological framework for the specific morphometric the features of Pech-de-l'Azé I Neandertal child, this study is a new step toward the understanding of temporal and spatial changes in the ontogenesis of Neandertals in south-western Europe during oxygen isotope stages 5-3.     

U-Series dating of Liujiang hominid site in Guangxi,Southern China

It has been established that modern humans were living in the Levant and Africa ca. 100ka ago. Hitherto, this has contrasted with the situation in China where no unequivocal specimens of this species have been securely dated to more than 30ka. Here we present the results of stratigraphic studies and U-series dating of the Tongtianyan Cave, the discovery site of the Liujiang hominid, which represents one of the few well-preserved fossils of modern Homo sapiens in China. The human fossils are inferred to come from either a refilling breccia or a primarily deposited gravel-bearing sandy clay layer. In the former case, which is better supported, the fossils would date to at least approximately 68ka, but more likely to approximately 111-139ka. Alternatively, they would be older than approximately 153ka. Both scenarios would make the Liujiang hominid one of the earliest modern humans in East Asia, possibly contemporaneous with the earliest known representatives from the Levant and Africa. Parallel studies on other Chinese localities have provided supporting evidence for the redating of Liujiang, which may have important implications for the origin of modern humans.     

New Luminescence Ages for the Galería Complex Archaeological Site: Resolving Chronological Uncertainties on the Acheulean Record of the Sierra de Atapuerca,Northern Spain

The archaeological karstic infill site of Galería Complex, located within the Atapuerca system (Spain), has produced a large faunal and archaeological record (Homo sp. aff. heidelbergensis fossils and Mode II lithic artefacts) belonging to the Middle Pleistocene. Extended-range luminescence dating techniques, namely post-infrared infrared stimulated luminescence (pIR-IR) dating of K-feldspars and thermally transferred optically stimulated luminescence (TT-OSL) dating of individual quartz grains, were applied to fossil-bearing sediments at Galería. The luminescence dating results are in good agreement with published chronologies derived using alternative radiometric dating methods (i.e., ESR and U-series dating of bracketing speleothems and combined ESR/U-series dating of herbivore teeth), as well as biochronology and palaeoenvironmental reconstructions inferred from proxy records (e.g., pollen data). For the majority of samples dated, however, the new luminescence ages are significantly (∼50%) younger than previously published polymineral thermoluminescence (TL) chronologies, suggesting that the latter may have overestimated the true burial age of the Galería deposits. The luminescence ages obtained indicate that the top of the basal sterile sands (GIb) at Galería have an age of up to ∼370 thousand years (ka), while the lowermost sub-unit containing Mode II Acheulean lithics (base of unit GIIa) was deposited during MIS 9 (mean age = 313±14 ka; n = 4). The overlying units GIIb-GIV, which contain the richest archaeopalaeontological remains, were deposited during late MIS 8 or early MIS 7 (∼240 ka). Galería Complex may be correlative with other Middle Pleistocene sites from Atapuerca, such as Gran Dolina level TD10 and unit TE19 from Sima del Elefante, but the lowermost archaeological horizons are ∼100 ka younger than the hominin-bearing clay breccias at the Sima de los Huesos site. Our results suggest that both pIR-IR and single-grain TT-OSL dating are suitable for resolving Middle Pleistocene chronologies for the Sierra de Atapuerca karstic infill sequences.     

Optical dating of dune sands in the northeastern deserts of China

Optical dating has been used to obtain the ages of fossil-stabilized sand dunes from four sections in the northeastern deserts of China. Our results indicate that the optically stimulated luminescence ages of the four sections correlate well, even though the samples were collected from different deserts about 600 km apart. Our results also indicate that active dune formation in this region lasted from the Last Glacial Maximum to about 10 ka, and that the warm climate of the Holocene was interrupted by a cold/dry dune formation episode about 3.5-1.7 ka. The Holocene Optimum in this region is between 10 and 3.6 ka, and a later warm/humid dune stabilization phase lasted from at least 1.6 to 1.0 ka. The youngest age on the uppermost sand unit yielded an age of only 40 yr, supporting the previous argument that the existence of modern active eolian sands in the regions with a mean annual precipitation of up to 450 mm is not mainly due to drought, but to extensive land cultivation over historic time. From the luminescence properties of the quartz grains, it is hypothesized that the sands in most of the sections are probably derived from more than one source, with a minor source of quartz having a different thermal history before deposition.     

High-precision U-series dating of Locality 1 at Zhoukoudian, China

Thermal ionization mass spectrometric(230)Th/(234)U dating has been carried out on intercalated speleothem samples from the limestone cave occupied by Homo erectus at Zhoukoudian, China. The samples were recently collected in proper stratigraphic context after detailed field examinations. The results show that the age of the No. 5 Skull from Layer 3 is >400 ka, possibly in the range of about 400-500 ka, and that the hominid fossils from the lower strata are at least 600 ka and possibly >800 ka, much older than previously thought. The near-equilibrium(230)Th/(234)U ratios and internal consistency of the dates and stratigraphy lend credence to the results and allow us to comment on their important implications for human evolution.     

Application of U/Th and 40Ar/39Ar Dating to Orgnac 3, a Late Acheulean and Early Middle Palaeolithic Site in Ardèche,France

Refined radio-isotopic dating techniques have been applied to Orgnac 3, a Late Acheulean and Early Middle Palaeolithic site in France. Evidence of Levallois core technology appeared in level 4b in the middle of the sequence, became predominant in the upper horizons, and was best represented in uppermost level 1, making the site one of the oldest examples of Levallois technology. In our dating study, fourteen speleothem samples from levels 7, 6 and 5b, were U/Th-dated. Four pure calcite samples from the speleothem PL1 (levels 5b, 6) yield ages between 265 ± 4 (PL1-3) and 312 ± 15 (PL1-6) thousand years ago (ka). Three samples from the top of a second stalagmite, PL2, yield dates ranging from 288 ± 10 ka (PL2-1) to 298 ± 17 ka (PL2-3). Three samples from the base of PL2 (level 7) yield much younger U/Th dates between 267 and 283 ka. These dates show that the speleothems PL1 and PL2 are contemporaneous and formed during marine isotope stage (MIS) 9 and MIS 8. Volcanic minerals in level 2, the upper sequence, were dated by the ⁴⁰Ar/³⁹Ar method, giving a weighted mean of 302.9 ± 2.5 ka (2σ) and an inverse isochron age of 302.9 ± 5.9 ka (2σ). Both ⁴⁰Ar/³⁹Ar dating of volcanic sanidines and U/Th dating of relatively pure and dense cave calcites are known to be well established. The first parallel application of the two geochronometers to Orgnac 3 yields generally consistent results, which point to the reliability of the two methods. The difference between their age results is discussed.     

A critique of the chronometric evidence for hominid fossils: I. Africa and the Near East 500-50 ka

The chronometric dating evidence for all hominid fossils from Africa and the Near East that have previously been dated to 500-50 ka is critically assessed using the concept of chronometric hygiene, and these dates are revised using Bayesian statistical analyses where possible. Sixteen relevant hominid sites lacking chronometric evidence are briefly discussed. Chronometric evidence from 37 sites is assessed in detail. The dates for many hominid fossils are poorly constrained, with a number dated by comparisons of faunal assemblages-a method that does not have good chronological resolution for much of the last million years. For sites with stratigraphic sequences of dates, it is generally possible to refine the dating, but in some cases, the revised chronology is less precise than previous chronologies. Fossils over 200 ka in age tend to be poorly dated, but for the last 200 kyr, dating is better due to the availability of electron-spin-resonance and thermoluminescence dating. Consideration of the chronologies favored by the proponents of the out-of-Africa and multiregional hypotheses of human evolution shows their selectivity. The chronological assessment of the fossils here is compatible with either hypothesis. If evolutionary schemes that do not rely on the morphology of the hominid fossils to decide the sequence of fossils are to be built, then further dating is required, alongside full publication of existing dates.