An attempt was made to test the validity of the signatures of rare earth elements （REE） as a tool to judge the effect of diagenesis on fossil teeth. Sample REE contents and features of fossil teeth and sediments fro...An attempt was made to test the validity of the signatures of rare earth elements （REE） as a tool to judge the effect of diagenesis on fossil teeth. Sample REE contents and features of fossil teeth and sediments from Jinsha Relics, Sichuan, Southwest China were analyzed. The difference in REE content between fossil teeth is significantly greater than that between sediments at the Jinsha Relics. Chondrite-normalized REE patterns showed that obvious LREE enrichment and strong Ce and HREE depletion occurred in all fossil teeth samples. Meanwhile δCe and δEu values varied more dramatically in fossil teeth than in sediments. Accordingly, low content, LREE enrichment, strong Ce depletion, the significantly positive correlation between LREE/HREE and δCe, and unchanged （La/Yb）N demonstrated that the fossil teeth from Jinsha Relics have not been contaminated by diagenesis. The REE signature might be a potential proxy to assess the effect of diagenesis on fossil teeth.展开更多
Lianhua Cave in the southern suburb of Zhengjiang City is one of the few hominid fossil-containing localities in Jiangsu Province.A human lower molar and numerous mammalian fossils of 16 species were recovered during ...Lianhua Cave in the southern suburb of Zhengjiang City is one of the few hominid fossil-containing localities in Jiangsu Province.A human lower molar and numerous mammalian fossils of 16 species were recovered during an excavation season in 1981. Based on biostratigraphic studies,this site has been assigned to Late Pleistocene in time. 230Th/ 234U and 227Th/ 230Th age determinations were carried out on two in situ collected mammalian teeth,obtaining broadly consistent dates ranging from 104 to 136 ka,which should be indicative to the age of the hominid tooth.Morphologically the human tooth has been classified to late \%Homo sapiens\%. If correct,the present dates imply an early presence of late \% Homo sapiens\% in the lower reaches of Yangtse River.Parallel studies on Ganqian (Tubo),Liujiang and Bailiandong hominid sites in Guangxi,southern China,yielded similar results.Taken together,much earlier than previously estimated appearance of modern humans might be a general phenomenon in extended areas of China.展开更多
四极杆电感耦合等离子体质谱仪(Inductively Coupled Plasma-Quadrupole Mass Spectrometry,简称ICP-QMS)可用于U和Th同位素分析。目前,ICP-QMS能实现精度大约为0.3%(U)和1%(Th)的测量分析,可提供误差在1%～10%的^(230)Th/U年代数据。...四极杆电感耦合等离子体质谱仪(Inductively Coupled Plasma-Quadrupole Mass Spectrometry,简称ICP-QMS)可用于U和Th同位素分析。目前,ICP-QMS能实现精度大约为0.3%(U)和1%(Th)的测量分析,可提供误差在1%～10%的^(230)Th/U年代数据。本文用ICP-QMS分析了采自意大利南都Loreto旧石器地点的4颗马牙化石样品,并对已发表的UTEVA树脂提纯U和Th的流程做了进一步改进,使其适用于动物牙化石样品。样品中的U和Th含量的平均测量精度(2σ)分别为0.3%和0.6%;^(234)U/^(238)U和^(230)Th/^(238)U活度比平均精度(2σ)分别为0.3%和0.8%。数据表明同一颗牙化石的不同组织的U含量可有数量级差别,同时它们的U-Th同位素活度比也可显著地离散(>2σ),从而导致不一致的^(230)Th/U年代结果。如今测定的各牙组织的U-Th同位素数据可用于模拟U的迁移历史;U-系分析与电子自旋共振测年技术相结合或可更好地估计样品的地质年代。展开更多
The hominin record from southern Asia for the early Late Pleistocene epoch is scarce.Well-dated and well-preserved fossils older than 45.000 years that can be unequivocally attributed to H.sapiens are lacking.In a pap...The hominin record from southern Asia for the early Late Pleistocene epoch is scarce.Well-dated and well-preserved fossils older than 45.000 years that can be unequivocally attributed to H.sapiens are lacking.In a paper published October 15 online in Nature,Dr.LIU Wu from Institute of Vertebrate Paleontology and Paleoanthropology（IVPP）.CAS,and his international team announced the discovery of human teeth between 80.000 and120,000 years old from the newly excavated Fuyan Cave in Daoxian.southern China,展开更多
基金supported by the Program for New Century Excellent Talents in University (NCET-08-0379) the National Science and Technology Advancement of the Tenth Five-year Plan (2004BA810B05)
文摘An attempt was made to test the validity of the signatures of rare earth elements （REE） as a tool to judge the effect of diagenesis on fossil teeth. Sample REE contents and features of fossil teeth and sediments from Jinsha Relics, Sichuan, Southwest China were analyzed. The difference in REE content between fossil teeth is significantly greater than that between sediments at the Jinsha Relics. Chondrite-normalized REE patterns showed that obvious LREE enrichment and strong Ce and HREE depletion occurred in all fossil teeth samples. Meanwhile δCe and δEu values varied more dramatically in fossil teeth than in sediments. Accordingly, low content, LREE enrichment, strong Ce depletion, the significantly positive correlation between LREE/HREE and δCe, and unchanged （La/Yb）N demonstrated that the fossil teeth from Jinsha Relics have not been contaminated by diagenesis. The REE signature might be a potential proxy to assess the effect of diagenesis on fossil teeth.
文摘Lianhua Cave in the southern suburb of Zhengjiang City is one of the few hominid fossil-containing localities in Jiangsu Province.A human lower molar and numerous mammalian fossils of 16 species were recovered during an excavation season in 1981. Based on biostratigraphic studies,this site has been assigned to Late Pleistocene in time. 230Th/ 234U and 227Th/ 230Th age determinations were carried out on two in situ collected mammalian teeth,obtaining broadly consistent dates ranging from 104 to 136 ka,which should be indicative to the age of the hominid tooth.Morphologically the human tooth has been classified to late \%Homo sapiens\%. If correct,the present dates imply an early presence of late \% Homo sapiens\% in the lower reaches of Yangtse River.Parallel studies on Ganqian (Tubo),Liujiang and Bailiandong hominid sites in Guangxi,southern China,yielded similar results.Taken together,much earlier than previously estimated appearance of modern humans might be a general phenomenon in extended areas of China.
文摘四极杆电感耦合等离子体质谱仪(Inductively Coupled Plasma-Quadrupole Mass Spectrometry,简称ICP-QMS)可用于U和Th同位素分析。目前,ICP-QMS能实现精度大约为0.3%(U)和1%(Th)的测量分析,可提供误差在1%～10%的^(230)Th/U年代数据。本文用ICP-QMS分析了采自意大利南都Loreto旧石器地点的4颗马牙化石样品,并对已发表的UTEVA树脂提纯U和Th的流程做了进一步改进,使其适用于动物牙化石样品。样品中的U和Th含量的平均测量精度(2σ)分别为0.3%和0.6%;^(234)U/^(238)U和^(230)Th/^(238)U活度比平均精度(2σ)分别为0.3%和0.8%。数据表明同一颗牙化石的不同组织的U含量可有数量级差别,同时它们的U-Th同位素活度比也可显著地离散(>2σ),从而导致不一致的^(230)Th/U年代结果。如今测定的各牙组织的U-Th同位素数据可用于模拟U的迁移历史;U-系分析与电子自旋共振测年技术相结合或可更好地估计样品的地质年代。
文摘The hominin record from southern Asia for the early Late Pleistocene epoch is scarce.Well-dated and well-preserved fossils older than 45.000 years that can be unequivocally attributed to H.sapiens are lacking.In a paper published October 15 online in Nature,Dr.LIU Wu from Institute of Vertebrate Paleontology and Paleoanthropology（IVPP）.CAS,and his international team announced the discovery of human teeth between 80.000 and120,000 years old from the newly excavated Fuyan Cave in Daoxian.southern China,
