New dating indicates intermittent human occupation of the Nwya Devu Paleolithic site on the high-altitude central Tibetan Plateau during the past 45,000 years

The timing and mechanisms of the human occupation of the demanding high-altitude Tibetan Plateau environment are of great interest.Here,we report on our reinvestigations and dating of the Nwya Devu site,located nearly 4600 meters above sea level on the central Tibetan Plateau.A new microblade techno-complex was identified on a lower lake shore at this site,distinct from the previously reported blade tool assemblage.These two lithic assemblages were dated to 45.6±2.6 and10.3±0.5 ka using optically stimulated luminescence and accelerator mass spectrometry^(14)C methods.They represent,respectively,the earliest known Paleolithic and microlithic sites on the interior Tibetan Plateau,indicating multiple occupation episodes of hunter-gatherers during the past 45 ka.Our studies reveal that relatively stable depositional conditions and a paleoenvironment characterized by a comparatively warm climate facilitated these multiple occupations at Nwya Devu.The contemporaneous occurrence of the Upper Paleolithic blade technology on the Tibetan Plateau and most of Eurasia between 50 and 40 ka indicates rapid,large-scale dispersals of humans that profoundly affected human demography on a large scale.Combining new archaeological evidence and previously reported genetic data,we conclude that the Tibetan Plateau provided a relatively stable habitat for Upper Paleolithic hunter-gatherers,which may have contributed to the complex and multiple-origin gene pool of present-day Tibetans.

The earliest evidence for a microblade adaptation in the remote,high altitude regions of the Tibetan Plateau

Microblade assemblages are among the most common prehistoric archaeological materials found on the Tibetan Plateau(TP)and are thought to indicate large scale migration to and settlement of the TP.Few microblade sites,however,have been systematically excavated,especially in the remotest,highest-elevation regions of the TP.The timing of the large-scale arrival,spread,and permanent settlement of people on the TP therefore remains controversial.In this paper,we report on a recently excavated site,Locality 3 of the Nwya Devu Site(ND3),located at 4600 meters above sea level(masl),near the shore of Ngoin Lake,on the interior TP.Our analyses reveal a fairly typical microblade technological orientation and two types of microblade cores:wedge-shaped and semi-conical,which are similar to those found throughout North China.Using Optically Stimulated Luminescence(OSL)dating and AMS^(14)C dating,the age of ND3 ranges from 11 to 10 ka.This date range indicates ND3 is the oldest microblade site yet recorded in the remote,high-elevation regions of the TP and thus provides important information about when and how hunter-gatherers using microblades began exploiting the higher altitudes of the TP.Taken together,studies at ND3 and throughout the TP suggest that a microblade adaptation is associated with the first prolonged human occupation of the plateau and that microblades played a significant role in mediating the risks and facilitating the mobility necessary to permanently inhabit the TP.

Massive cranium from Harbin in northeastern China establishes a new Middle Pleistocene human lineage

It has recently become clear that several human lineages coexisted with Homo sapiens during the late Middle and Late Pleistocene.Here,we report an archaic human fossil that throws new light on debates concerning the diversification of the Homo genus and the origin of H.sapiens.The fossil was recovered in Harbin city in northeastern China,with a minimum uranium-series age of 146 ka.This cranium is one of the best preserved Middle Pleistocene human fossils.Its massive size,with a large cranial capacity(
1,420 mL)falling in the range of modern humans,is combined with a mosaic of primitive and derived characters.It differs from all the other named Homo species by presenting a combination of features,such as long and low cranial vault,a wide and low face,large and almost square orbits,gently curved but massively developed supraorbital torus,flat and low cheekbones with a shallow canine fossa,and a shallow palate with thick alveolar bone supporting very large molars.The excellent preservation of the Harbin cranium advances our understanding of several less-complete late Middle Pleistocene fossils from China,which have been interpreted as local evolutionary intermediates between the earlier species Homo erectus and later H.sapiens.Phylogenetic analyses based on parsimony criteria and Bayesian tip-dating suggest that the Harbin cranium and some other Middle Pleistocene human fossils from China,such as those from Dali and Xiahe,form a third East Asian lineage,which is a part of the sister group of the H.sapiens lineage.Our analyses of such morphologically distinctive archaic human lineages from Asia,Europe,and Africa suggest that the diversification of the Homo genus may have had a much deeper timescale than previously presumed.Sympatric isolation of small populations combined with stochastic long-distance dispersals is the best fitting biogeographical model for interpreting the evolution of the Homo genus.

Geochemical provenancing and direct dating of the Harbin archaic human cranium

As one of the most complete archaic human fossils,the Harbin cranium provides critical evidence for studying the diversification of the Homo genus and the origin of Homo sapiens.However,the unsystematic recovery of this cranium and a long and confused history since the discovery impede its accurate dating.Here,we carried out a series of geochemical analyses,including non-destructive X-ray fluorescence(XRF),rare earth elements(REE),and the Sr isotopes,to test the reported provenance of the Harbin cranium and get better stratigraphic constraints.The results show that the Harbin cranium has very similar XRF element distribution patterns,REE concentration patterns,and Sr isotopic compositions to those of the Middle Pleistocene-Holocene mammalian and human fossils recently recovered from the Harbin area.The sediments adhered in the nasal cavity of the Harbin cranium have a 87Sr/86Sr ratio of 0.711898,falling in the variation range measured in a core drilled near the Dongjiang Bridge,where the cranium was discovered during its reconstruction.The regional stratigraphic correlations indicate that the Harbin cranium was probably from the upper part of the Upper Huangshan Formation of the Harbin area,which has an optically stimulated luminescence dating constraint between 138 and 309 ka.U-series disequilibrium dating(n=10)directly on the cranium suggests that the cranium is older than 146 ka.The multiple lines of evidence from our experiments consistently support the theory that the Harbin cranium is from the late Middle Pleistocene of the Harbin area.Our study also shows that geochemical approaches can provide reliable evidence for locating and dating unsystematically recovered human fossils,and potentially can be applied to other human fossils without clear provenance and stratigraphy records.

东北平原钻孔的磁性地层定年及松嫩古湖演化

中国东北平原第四纪湖相沉积物是记录中纬度东亚季风和气候环境变化的理想载体.然而,目前关于该套湖相沉积地层尚缺乏高分辨率地层学和高精度的年代学研究,从而限制了对该区气候环境变化机理的理解.本研究重建了东北平原乾安令字(Qiananlingzi, QAL)孔的高分辨率磁化率地层,并对该套沉积进行了系统的古地磁和光释光年代学研究.结果显示, QAL钻孔记录了Olduvai正极性亚时以来的沉积.沉积物磁化率变化存在轨道时间尺度上的变化,粗颗粒的粉砂层一般呈现磁化率低值,细颗粒的黏土层一般呈现高值,岩石磁学参数表明磁化率低值层位高矫顽力硬磁性矿物贡献大,高值层位低矫顽力软磁性矿物贡献大;该套湖相地层的沉积年代约为1180～450ka,历时约730ka,松嫩古湖的几近消失可能与依舒断裂导致的多次沉降使得松花江将松嫩古湖湖水泄于三江平原有关.基于本文详细的磁化率地层和高精度的年代学结果,该湖相沉积有望成为解译中纬度中亚区域中更新世轨道时间尺度古气候变化的理想材料.

泥河湾黑土沟剖面磁组构特征及古湖水文环境变化

古人类栖息地古气候-水文环境变化与古人类的生存活动密切相关.泥河湾盆地保存着大量早更新世以来的古人类遗址,完整地记录了我国北方古人类的活动历史.但迄今对其水文环境变化历史以及与古人类生存活动联系的研究仍显不足.本研究对位于盆地东部的黑土沟遗址剖面进行了系统的磁化率地层学和磁组构研究.通过与邻近大长梁和小长梁剖面的精细磁化率地层对比,发现黑土沟剖面堆积约始于1.9 Ma,可能记录了我国北方中高纬地区最早的古人类活动.详细的磁组构研究结果显示,磁化率各向异性能够有效地揭示泥河湾盆地1.9 Ma以来的古水文变化,黑土沟剖面的磁组构变化显示泥河湾古湖水文环境发生了多次阶段性变化.1.9 Ma前后,壶流河的出现,抑或研究区发生构造沉降,使得研究区堆积厚层砂砾石,较强的水动力和水位升高使得古人类向高处迁移;1.9~1.8 Ma期间,古湖扩张,湖面上升,水动力减弱,可能指示了东亚夏季风的增强.1.8~1.5 Ma,古湖水动力显著增强,而后持续减弱.1.5~1.3 Ma,水动力显著降低,可能与东亚季风降水增加,气候逐渐变得暖湿,湖水显著加深,而使得河流输入影响减弱有关.1.3~0.9 Ma,水动力较强但呈现频繁的大幅波动,湖泊水文环境变化剧烈,可能是中更新世气候转型事件的响应.0.9~0.4 Ma,湖泊再度加深,古湖沉积水动力变化显著受控于全球冰量呈现周期性的大幅波动.上述水文变化显著影响着古人类的生活行为,很大程度上决定了泥河湾古人类遗址的时空分布特征.

The use of fire at Zhoukoudian:evidence from magnetic susceptibility and color measurements

In order to provide direct evidence for the use of fire by humans at Locality 1,Zhoukoudian,we examine the burnt and unburnt sediments of newly excavated area in Layer 4 by detailed measurements of magnetic susceptibility,color,and diffuse reflectance spectrum.Results show that the magnetic susceptibility and redness of the burnt sediments are remarkably higher than those of other areas on the same level:up to*22 times for magnetic susceptibility and*3 times for redness of those of the adjacent unburnt sediments.Fine-grained(superparamagnetic/stable single-domain)magnetite and hematite grains make dominant contributions to the distinctly high values of magnetic susceptibility and redness in the burnt sediments.Diffuse reflectance spectroscopy results show that the burnt sediments contain more hematite than those of other areas and localities 2 and 3.High-temperature magnetic susceptibility measurements demonstrate that the burnt sediments have been heated above 700°C.Those changes in low-frequency magnetic susceptibility and redness are impossibly resulted from natural fires,thus most likely signaling the human activities of controlled use of fire.However,further work is needed to confirm whether or not these heat-affected sediments were produced in situ.

早期现代人向青藏高原腹地的扩散之路

人类扩散至青藏高原腹地的时间可追溯至深海氧同位素3阶段晚期,目前我们对该历史过程知之甚少,西藏尼阿底遗址为探讨古代人群向高原扩散的行为模式提供了重要线索.石器技术分析与文化对比研究结果表明,尼阿底独特的石叶遗存为典型旧石器时代晚期石叶技术,由于高原上缺少更早或同时期的相关遗址,其来源指向低海拔地区.现有考古学证据表明,尼阿底与中国宁夏水洞沟和亚洲北部的考古遗址具有密切联系,是早期现代人迁徙和文化互动的结果.GIS最低成本路径分析提示,高原腹地与平原地区石叶技术人群的交流存在两条可能性较大的路线:一是西伯利亚和蒙古国北部横穿戈壁,经水洞沟连接高原腹地;二是北亚地区绕戈壁边缘经中国东北连通水洞沟及青藏高原.