A Middle Pleistocene Glaciation Record from Lacustrine Sediments in the Western Tibetan Plateau and Discussion on Climate Change

The Tibetan Plateau is an important area for studying global climate change,but the answers to many scientific problems remain unknown.Here,we present new information from the lacustrine sedimentary record in the western Tibetan Plateau,related to the third most-recent glaciations.Continuous sediment data,including sporopollen,particle size,total organic carbon,mass susceptibility,CaCO_(3),CaSO_(4),BaSO_(4)contents and chronological data,were reconstructed and revealed that climate and environmental conditions obviously and distinctly changed between 600 and 700 thousand years ago.In comparison,the data obtained from the Guliya ice core in this area also corresponds to the global glacial climatic characteristics recorded in basin sediments in the eastern and southeastern regions of the plateau and to the information obtained from ice cores in the Antarctic and Arctic regions.In this study,we conclude that the main reason for the glaciations and new tectonic movement must be a geomagnetic polarity reversal 774 thousand years ago(from Matuyama to Brunhes).Indeed,the results of this study suggest that the described reversal event might have influenced the current global climate pattern and will continue to impact climatic changes in the future.

Mechanical characteristics of intact Middle Pleistocene Epoch loess in northwestern China

In order to research the mechanical characteristics of intact Middle Pleistocene Epoch loess, triaxial shear tests and isotonic compression test of intact Middle Pleistocene Epoch loess were conducted by improved SJ-IA triaxial shear equipment. According to test results, it can be found that the intact Middle Pleistocene Epoch loess has the properties of shear dilatancy and shear shrinkage. With the increase of confining pressure, stress-strain curve develops from softening to hardening. The failure mode of intact Middle Pleistocene Epoch loess is shear failure with the rupture angle between 55° and 61°. And it is better to determine the yield stress （py, qy） of the intact loess under different confining pressures by using the εv-q/p curve. Along with the increase of confining pressure, yield deviatoric stress qy and yield spherical stress py present logarithmic relationship. Besides, the strength parameters, elastic modulus K and G of intact loess, are obtained, which are benefit for loess projects design.

Geochemistry and environment evolution of Core E in the Laizhou Bay since last stage of Middle Pleistocene

Geochemistry analysis has been done on Core E (37 07' N, 118 55' E; depth: 82.1 m) taken from the Laizhou Bay in 1994. Nine kinds of invariable elements, 15 kinds of microelements and the content of lime carbonate are measured by means of ICP. The results indicate that most of the invariable elements and microelements in Core E show significant changes in the boundary stratotype, and the ratios between elements (Mn/Fe, Sr/Ba, Ti/Al) in particular. So they can be used as characteristic indicator to stratigraphic division of Quaternary. The changes of invariable elements are primarily controlled by the host minerals, and they mainly indicate the provenance as well as the sedimentation and depositional environment. Several elements, such as Fe, Al, Ca, Mg, Mn and Ti, are very sensitive to the provenance and environment. The distribution of microelements differs in four depositional periods: last stage of Middle Pleistocene, last interglacial period, last glacial period and Recent epoch, and especially in the 'cold period' and 'warm period'. The loops in the cycle curves of the most microelements correspond with the sand bed sediments, among which there are six sand units representing 'warm period' sediments, and one representing 'cold period' sediments. The carbonate is on the high side in the aeolian silt sediments formed in the glacial lowering of sea level in Core E, but on the low side in the transgressive sand beds formed in the interglacial period. The content variation of carbonate has a direct bearing on the grain size and the styles of sediments, and is a good indicator to the climate, environment and stratigraphic division.

Cosmogenic ^(26)Al/^(10)Be Burial Dating of the Uplift Rate of Southern Qinling Mountains since the Middle Pleistocene

Objective The Qinling Mountains （QM） in Central China is a natural harrier that corresponds to the boundary between the southern and northern climate and environment （Gong Hujun et al., 2017）. Northern QM is relatively steep, and southern QM is in contrast relatively low and gentle. Investigations have shown that the average uplift rate of northern QM since 17.8 Ma is approximately 0.19 mm/a （Yin Gongming et al., 2001）, whereas that of central QM since 0.36 Ma is approximately 0.32 mm/a （Wang Fei et al., 2004）. To date, however, few investigations have yet been conducted on the uplift rate of southern QM. Accordingly, we aim to obtain the uplift rate of southern QM by using the cosmogenic ^26A1/^10 Be burial dating method to determine the age of the highest river terrace on the southern slope of QM.

A new molar from the Middle Pleistocene hominid assemblage of Yanhuidong, Tongzi, South China

1988年,贵州省博物馆对桐梓岩灰洞的支洞进行了最后一次发掘。2014年,在洞内第四层堆积物中鉴定出逾2000件的动物牙齿化石,以及一枚古人类上颊齿(编号:TZ-1)。1991年,铀系法测定这些次生堆积物的沉积年代约为距今24万年。本文运用高精度CT(巴黎自然历史博物馆)对TZ-1的釉质齿质界面(EDJ)和牙髓腔几何形态进行了分析。TZ-1的冠面形态有如下特征:次尖小且在远中舌侧不发育,咀嚼面轮廓呈四边形,颊舌径稍大过近中远中径,原尖舌侧齿带发育,齿尖从大到小依次为原尖、后尖、前尖和次尖。TZ-1牙髓腔的髓角与其釉质齿质界面以及釉质表面的形态都具有相关性。TZ-1的形态与M1虽有相似之处,但完全不同于1983年出土于同一层位的另两颗M1;其应被鉴定为dm2,并可被归入中中更新世的中国直立人支系。岩灰洞上臼齿PA 875的形态与建始龙骨洞PA 1279和周口店直立人等古老型直立人相似。岩灰洞另一枚刚萌发的臼齿PA 874具有凸出的次尖和长菱形的外廓,接近于爪哇型直立人Sangiran NG 91-G10;这也是智人和尼安德特人的共有衍征。但PA 874的冠面仍保留了亚洲型的齿带,因而被归入人属未定种。因出土自次生堆积,岩灰洞的三种古人类类型未必曾同时并存,但却揭示了华南地区人类演化进程中的多样面貌。

Palynoflora and climatic dynamics of the Laizhou Bay of Bohai Sea,North China Plain,since the late middle Pleistocene

The coastal plain of Laizhou Bay in Bohai Sea is a transitional area of land-sea interaction.Sediments in this area can bear significant information of sea-level fluctuation,climate change,as well as regional geological setting.Here,in this study,new sporopollen data from three boreholes(GK138,GK111 and GK95)in the coastal plain of Laizhou Bay,Bohai Sea were investigated,and the pollen spectrum since the late middle Pleistocene was established as six sporopollen assemblage zones(Ⅰ-Ⅵ),i.e.,Pinus-Quercus-Artemisia,Gramineae-Artemisia-Chenopodiaceae,Picea-Pinus-QuercusArtemisia,Picea-Pinus-Betula-Gramineae-Artemisia,Picea-Pinus-Cupressaceae-Chenopodiaceae and Pinus-Quercus-Gramineae-Artemisia-Chenopodiaceae.Combining with existing sedimentary successions and detailed radiocarbon dating results of the sediments from the three boreholes,paleovegetation and climatic evolution since the late middle Pleistocene were reconstructed.The findings revealed that climatic changes in this area since the late middle Pleistocene were characterized by alternating cold-arid and warmhumid conditions,which were well correlated with marine isotopic stages(MIS).The present study offers specific insight into the climatic dynamics in the North China Plain since the late middle Pleistocene and provides evidence of a clear link among the palynoflora in the area,the glacial-interglacial period climatedriven sea-level changes,and the marineδ^(18)O records.

Discovery of Middle Pleistocene Mammal Fauna From Tangshan Karst Cave, Nanjing and Its Significance

The material reported in this note was collected from Huludong (Calabash Cave), a karst cave at the northeastern extremity of Tangshan Hill, Nanjing. The cave is located on the hillside to the south of the Nanjing-Hangzhou Highway near the west verge of the Tangshan Town, Jiangning County, 26km east of the centre of Nanjing (32°N and 119°E). The bottom of this cave is 85.9m above sea level, with a relative height of about 75m from the local highway. This karst cave developed in the Ordovician limestone assumes the shape of an east-westward extending calabash, about 80m long,

The microtine distribution and its environmental significance since the Middle Pleistocene in Zhangping Caves of the Qinling Mountains

Three microtine species are recovered from the Zhangping Caves of the Qingling Mountains, namely Microtus oeconomus, Caryomys inez and Caryomys eva. They are climate-sensitive ones with different ecological habits, therefore their distribution well corresponds to environmental variations. Statistical comparison of the distribution of fossil microtines and their counterparts nowadays displays that the climate variation of the studied area and its contiguity since the middle Pleistocene are: warm and humid at 493 ka ago, cool and humid at 259 ka ago―cold and humid at 205 ka ago―cool and humid at 28 ka ago, and warm and dry at present.

THE DISCOVERY AND PRELIMINARY STUDY OF TRANSGRESSION IN THE MIDDLE PLEISTOCENE IN SOUTH CHINA

Many marine-fresh fossil diatoms have been found in some sections of Hegang, Gangmei of Sihui County and Bahai of Sanshui County ( Fig. 1). They lie about 50 km to the northwest of Guangzhou city. The altitude of sediments is about 25-35 m. The TL ages of sediments are from 18.0±1.4 × 10~4 a to 55.9±5.6 × 10~4 a. It indicates that these

Middle Pleistocene mammalian fauna of Shanyangzhai cave in Qinhuangdao area, China and its zoogeographical significance

The mammalian fauna with clear characteristics of transitional region has been found in the Shanyangzhai cave of the Qin-huangdao area where the three Chinese zoogeographical regions (the Northeast region, the North region and the Mengxin region) join. Abundant fossils mainly are small mammals. The fauna includes typical species derived from three zoogeographical regions and can be compared with the middle Pleistocene faunas found in both the Zhoukoudian (the North region) and the Jinniushan (the Northeast region) faunas. Of 53 kinds of mammals identified at the site, 38 kinds can be seen on the list of the middle Pleis-tocene Zhoukoudian and the Jinniushan faunas, of which 29 kinds are the same as those in the Zhoukoudian fauna and 25 are in the Jinniushan fauna, 7 in the Salawusu fauna and account for 76%, 66% and 18% of the total, respectively. It is suggested based on the consistence of the constitution of the fauna and its recent zoogeographic division that the three regions in north China could be initially formed during the middle Pleistocene.

中更新世晚期许家窑人化石的研究进展

许家窑人类化石在1976-1979年发现于泥河湾盆地北部许家窑遗址(又名许家窑-侯家窑遗址)的74703地点。化石包括1件儿童左侧上颌骨、3颗游离臼齿、2块枕骨、1件上颌支残段和13块顶骨碎片,代表约16个个体,生存于中更新世晚期。对于许家窑人的演化地位,长期以来学者们一直持有不同观点,分别将其归入直立人、尼安德特人、早期智人或者未知人群。最新研究显示:许家窑人的牙齿、头盖骨和下颌骨的形态都具有原始与进步混合的特征;许家窑个体呈现有罕见的先天巨顶孔缺陷遗传疾病、暴力冲突产生的创伤愈合痕迹、因营养缺乏导致的牙齿釉质发育不良及适应潜水环境产生有耳圆枕结构;许家窑人的颅容量为1700 mL以上,其上颌骨内鼻底、颞骨内耳迷路和枕圆枕的形态类似尼安德特人,牙齿生长发育模式接近现代人。许家窑人特殊的形态特征,特别是低而宽的头盖部和巨大的颅容量,与许昌人头骨形态相近,二者可能代表中更新世晚期-晚更新世早期东亚境内生存的一种新型古老型人类——巨颅人,可能是欧洲先驱人或者尼安德特人的祖先向东亚扩散,与东亚直立人杂交的后代。

晚中更新世以来武威盆地沉积特征——基于wv3钻孔的释光年代学研究

青藏高原东北缘河西走廊形成了一系列新生代盆地,是研究盆地沉积演化的重要区域。武威盆地位于河西走廊东部,盆地内沉积了较厚的新生代冲洪积地层。为了厘清武威盆地晚中更新世以来的沉积演化历史,笔者等在武威盆地石羊河中—上游处钻取了长207 m的wv3钻孔岩芯,获得了上部17 m岩芯的19个钾长石两步法pIR200 IR290年龄和2个多步法MET-pIRIR年龄,结合粒度资料,重建了武威盆地石羊河流域中—下游晚中更新世以来的光释光年代学框架和沉积历史。结果表明:两步法pIR200 IR290和多步法MET-pIRIR年龄在误差范围内一致。220~128 ka时期,沉积速率最小,为0.35 mm/ka,水动力条件较强,以侵蚀为主;128~108 ka(MIS 5d、MIS 5e)时期沉积速率为1.94 mm/ka,沉积物粒径由粗变细,表明此时水动力条件由强变弱;末次冰盛期到全新世早期(19~9 ka)沉积速率为2.78 mm/ka,沉积物粒径较细,表明此时水动力条件较弱,沉积速率最大,沉积为主。该地区新构造运动比较活跃,在末次间冰期至末次冰盛期期间存在逆冲活动。该研究对于揭示晚中更新世以来祁连山东北部石羊河流域沉积演化特征具有重要意义。

2021年河南南召新发现的旧石器

2021年,在南召县发现8处旧石器地点,石制品400余件。通过地层比对,小余坪西山、余坪、瓦房庄西山、杏花山猿人、沈家庄东山和南坡根6处地点暂归为中更新世中期,距今50~60万年;钟店西南山和白果树西南山2处地点暂归为中更新世晚期。对各地点的石器工艺流程复原、技术特点等比对发现,均体现石核—石片技术。从石器大小上分析,钟店西南山、小余坪西山、白果树南山、瓦房庄西山和沈家庄东山地点属于华北小石器工业,余坪和南坡根地点显示出南北方过渡的工业特征。这几处地点的石器工艺比1980、1987年小空山上洞和下洞遗址的更为原始。从石制品原料利用率、器类组合、石器加工技术等方面分析,钟店西南山、余坪、白果树西南山3处地点与上洞遗址更为接近;从剥片技术和石器大小上分析,又比上洞遗址更为原始,可能具有发展关系。

Magnetic minerals in Mid-Pleistocene sediments on the Caiwei Guyot,Northwest Pacific and their response to the Mid-Brunhes climate event

Seamounts are ubiquitous topographic units in global oceans,and their influences on local oceanic circulation have attracted great attention in physical oceanography;however,previous efforts were less made in paleoclimatology and paleoceanography.The Caiwei Guyot in the Magellan Seamounts of the western Pacific is a typical seamount,and in this study,we investigate a well-dated sediment core by magnetic properties to reveal the relationship between deep-sea sedimentary processes and global climate changes.The principal results are as follows:(1)the dominant magnetic minerals in the sediments are low-coercivity magnetite in pseudo-single domain range,probably including a biogenic contribution;(2)the variabilities of magnetic parameters can be clustered into two sections at~500 ka,and the differences between the two units are evident in amplitudes and means;(3)changes in the grainsize-dependent magnetic parameters can be well correlated to records of global ice volume and atmospheric CO;in the middle Pleistocene.Based on these results,a close linkage was proposed between deep-sea sedimentary processes in the Caiwei Guyot and global climate changes.This linkage likely involves different roles of biogenic magnetite in the sediments between interglacial and glacial intervals,responding to changes in marine productivity and deep-sea circulation and displaying a major change in the MidBrunhes climate event.Therefore,we proposed that the sedimentary archives at the bottom of the Caiwei Guyot record some key signals of global climate changes,providing a unique window to observe interactions between various environmental systems on glacial-interglacial timescales.

Pleistocene Birds of Gruta Nova da Columbeira(Bombarral-Portugal):A Paleontological and Paleoenvironmental Aproach

Discovered in 1962,the Columbeira cave has a Mousterian sequence dated between 101 and 35 Ka(U-series)and between 28,900 and 18,000 BP 14C.Excavations recovered abundant lithic implements and provided rich assemblage of vertebrates,including mammals,reptiles,birds and a remain of Homo neanderthalensis.In this work,authors present the taxonomy at the level of genus and species of the bird assemblage and its possible relationship with the paleoenvironments in which they lived.Thirteen species of birds have been identified out of 283 bones.Most of these bones are very fragmented and unsuitable for identification down to species or the genus level.Nevertheless,it is possible to say that the species vary through the sequence and that the assemblage is dominated by Pyrrhocorax,Corvus,Columba Turdus and Alectoris.

青藏高原定结盆地中更新世孢粉记录及其环境意义

西藏定结盆地叶如藏布东岸剖面为一套灰与灰白色黏土质砂、粉砂、细砂与粗砂层所组成的湖相沉积地层,厚约41.3 m,ESR和U系测年数据显示该地层沉积时间介于距今551.6~202.4 ka的中更新世时期。该套地层的孢粉化石丰富,依据孢粉化石类型与丰度变化,自下而上可分为5个孢粉带。结合测年结果、孢粉和介形类记录,定结盆地中更新世的古环境变化阶段为:551.6~448.4 ka,气候温暖湿润,适宜植物生长;448.4~375.2 ka,气候向冷干转化;375.2~291.2 ka,气候波动频繁,呈现冷湿—冷干—冷湿的变化过程;291.2~261.0 ka,气候进一步趋于干冷;261.0~202.4 ka,气候波动频繁,表现为冷干—暖湿—冷干的变化过程。

宁夏清水河盆地晚更新世中晚期孢粉记录及古气候意义

亚洲内陆荒漠化和干旱化与中国西部人类生存环境和社会可持续发展密切相关。中国西部地区的气候自晚更新世以来经历了多次冷暖、干湿变化,研究其晚更新世古气候变化,有助于预测未来气候的变化趋势。文章分析了宁夏南部清水河盆地晚更新世中晚期的孢粉记录,结果显示孢粉序列可从下至上划分为4个组合带,反映了该地区晚更新世中晚期植被和气候变化规律。研究表明研究区晚更新世中期(75~50 ka B.P.)是植被以蒿属为主的干草原,气候温凉偏干;晚更新世晚期(25~15 ka B.P.)由荒漠草原-干草原和疏林草原交替出现逐渐过渡到荒漠草原,该时期冬季风呈现逐渐增强的趋势,致使气候逐渐变冷变干,气候类型由温凉偏湿过渡到冷干。宁夏南部清水河盆地晚更新世中晚期孢粉记录的深入研究对于正确认识黄土高原自然环境历史演变和黄土高原治理决策的制定具有重要指导意义。

宝鸡地区L_(1)-S_(5)黄土和古土壤水分入渗及影响因素

[目的]探究宝鸡中晚更新统L_(1)—S_(5)层黄土和古土壤层水分稳定入渗率变化特征及其与土壤容重、土壤初始含水量和土壤毛管孔隙度等土壤属性的关系,为揭示宝鸡中晚更新统L_(1)—S_(5)层黄土和古土壤的入渗规律提供参考依据。[方法]运用双环法进行入渗试验,探讨了宝鸡中晚更新统L_(1)—S_(5)层黄土和古土壤水分入渗的变化特征及其影响因素。[结果](1)宝鸡中晚更新统L_(1)—S_(5)黄土层的平均稳定入渗率(2.38 mm/min)大于古土壤层的平均稳定入渗率(1.55 mm/min),其差异的原因可能与形成时的气候与风化成壤作用的强弱有关。(2)L_(1)—S_(5)层黄土和古土壤层水分入渗试验过程可以用考斯加可夫和通用经验公式进行很好地拟合。(3)土壤容重、土壤初始含水量和土壤毛管孔隙度等土壤属性是影响L_(1)—S_(5)层黄土和古土壤层水分稳定入渗率变化的重要因素。(4)利用土壤容重、土壤毛管孔隙度和毛管最大持水量等土壤参数可以很好地模拟宝鸡中晚更新统L_(1)—S_(5)层黄土和古土壤层的土壤稳定入渗率(R 2=0.88,NSE=0.88)。[结论]宝鸡中晚更新统L_(1)—S_(5)层黄土和古土壤层水分稳定入渗率的变化主要由土壤容重、土壤初始含水量和土壤毛管孔隙度等土壤属性的变化所致,利用上述土壤参数可以较好地模拟该区中晚更新统L_(1)—S_(5)黄土和古土壤层土壤稳定入渗率的变化。

蔚县盆地吉家庄旧石器遗址动物骨骼的埋藏学分析

泥河湾盆地南部蔚县盆地区域的河湖相地层发育良好,并保存有丰富的考古材料与人类活动信息,在研究我国北方中更新世人类演化与行为方面有重要的价值。本文对蔚县盆地吉家庄遗址群4个地点出土的动物遗存进行了初步埋藏学观察与研究。结果显示,A与D地点的动物骨骼数量较少,反映的埋藏信息有限,不作为本文主要讨论对象;E地点出土的部分动物骨骼带有异地埋藏的特点,人类行为信息可能受到干扰,变得模糊;B地点动物化石接近原地埋藏,中更新世古人类应该是该地点动物资源的初级利用者与动物骨骼富集的主要动因。分析表明,B地点古人类于原地对大中型食草动物进行了肢解、割肉与敲骨取髓等多种活动,随后食肉动物又利用了这些动物骨骼的剩余营养成分,但动物骨骼数量与组成说明古人类在此地点的生存活动是短暂且有限的。

陕西洋县绿豆梁旧石器遗址出土的石制品

洋县绿豆梁遗址位于汉水北部一级支流金水河左岸的第四级阶地上。为了配合国家重点工程项目——南水北调西线“引汉济渭”工程的建设,2014~2015年对该地点进行了发掘,揭露面积126 m^(2),出土和采集不同类型的石制品656件。研究显示,早期人类加工石制品的原料来自于河漫滩或阶地古老砾石层中的砾石,岩性包括石英、石英岩、硅质灰岩、石英砂岩、花岗岩等。硬锤打击法是最主要的剥片方式。石制品包含石锤、石核、石片、石器、断块和碎屑等类型。遗址石器组合中既包括刮削器、尖状器、石钻等尺寸较小的轻型石器,也包含重型刮削器、砍砸器等重型石器。通过与位于相同阶地部位、相距2 km的金水河口遗址的测年数据和地层堆积序列对比,绿豆梁遗址的年代属于中更新世时期或更早的时段。