In this paper, we used ESR dating method to measure the accumulative dose of the fossil teeth samples, which are contemporaneous with the Peking-Man. The internal annual dose rate of samples are got by neutron activat...In this paper, we used ESR dating method to measure the accumulative dose of the fossil teeth samples, which are contemporaneous with the Peking-Man. The internal annual dose rate of samples are got by neutron activation analysis and the environmental annual dose rate by highly sensitive TL dosimeters to be embedded in cave deposits in the site. The results of ESR dating are corresponded with the dating results obtained by U-series, FT, TL and paleomagnetic stratigraphical methods on the 3rd, 4th, 7th and 10th layers. Calculation of using different models, the close-equilibrium model, the linear uranium accumulation model and radon loss-linear uranium accumulation model, for travertine, deer teeth and rhinoceros tooth, we obtained the age of the First Peking- Man in the nth layer is 578 ka and gave ages of other layers, from the 1st to the 13th layer in Peking- Man site.展开更多
Penguin and skua in the maritime Antarctic have high salt loadings in the body due to almost exclusive diet consumption of marine invertebrates.However,the storage and turnover of sodium and potassium in these animals...Penguin and skua in the maritime Antarctic have high salt loadings in the body due to almost exclusive diet consumption of marine invertebrates.However,the storage and turnover of sodium and potassium in these animals are poorly investigated.Here we determined the concentration and microscopic distribution of the two elements in the bones of penguin and skua.The average concentrations of sodium and potassium in penguin bone were comparable with that in skua bone(0.18% and 0.82% for penguin bone;0.19% and 0.76% for skua bone in dry weight).The ratios of sodium to calcium and potassium to calcium(0.0330 and 0.0075 for penguin,0.0335 and 0.0082 for skua in average by weight) were somewhat higher than the reported ratios for terrestrial animals,indicating these marine animals' bone enrichment of salt.The ratios of sodium to potassium in average by weight were 6.75 and 4.65 for penguin and skua,respectively.This value is much lower compared with the bulk sea water ratio of about 27.0,implying that potassium is favorable to reside in the bone rather than sodium.Both sodium and potassium were found to significant correlation with the content of organic materials in bone based upon the intensity of native signal determined by electron paramagnetic resonance(EPR).It was estimated that almost all of potassium is kept within the organic phases,while about 30% of sodium is stored in organic phases and the other 70% within mineral phase.The microscopic distributions of potassium in the cross-section and/or surface were revealed by synchrotron radiation Xray fluorescence(SR-XRF) technique.The ratio of potassium to calcium based upon the SR-XRF intensity counter varied considerably from the surface to the interior,and on the surface the highest concentration of potassium was observed in the middle section with decreasing amounts toward the edge.This indirectly documented that exchange of potassium between fluid and bone organic phase maybe occur.展开更多
文摘In this paper, we used ESR dating method to measure the accumulative dose of the fossil teeth samples, which are contemporaneous with the Peking-Man. The internal annual dose rate of samples are got by neutron activation analysis and the environmental annual dose rate by highly sensitive TL dosimeters to be embedded in cave deposits in the site. The results of ESR dating are corresponded with the dating results obtained by U-series, FT, TL and paleomagnetic stratigraphical methods on the 3rd, 4th, 7th and 10th layers. Calculation of using different models, the close-equilibrium model, the linear uranium accumulation model and radon loss-linear uranium accumulation model, for travertine, deer teeth and rhinoceros tooth, we obtained the age of the First Peking- Man in the nth layer is 578 ka and gave ages of other layers, from the 1st to the 13th layer in Peking- Man site.
基金supported by grants fromthe National Natural Science Foundation of China(project nos.40776001 and 40306001)the Foundation for the Author of National Excellent Doctoral Dissertation of China(grant200354)+2 种基金the Ministry of Education of China,and the Chinese Academy of Sciencessupported by the Chinese Arctic and Antarctic AdministrationSRXRF experiment is supported by BSRF
文摘Penguin and skua in the maritime Antarctic have high salt loadings in the body due to almost exclusive diet consumption of marine invertebrates.However,the storage and turnover of sodium and potassium in these animals are poorly investigated.Here we determined the concentration and microscopic distribution of the two elements in the bones of penguin and skua.The average concentrations of sodium and potassium in penguin bone were comparable with that in skua bone(0.18% and 0.82% for penguin bone;0.19% and 0.76% for skua bone in dry weight).The ratios of sodium to calcium and potassium to calcium(0.0330 and 0.0075 for penguin,0.0335 and 0.0082 for skua in average by weight) were somewhat higher than the reported ratios for terrestrial animals,indicating these marine animals' bone enrichment of salt.The ratios of sodium to potassium in average by weight were 6.75 and 4.65 for penguin and skua,respectively.This value is much lower compared with the bulk sea water ratio of about 27.0,implying that potassium is favorable to reside in the bone rather than sodium.Both sodium and potassium were found to significant correlation with the content of organic materials in bone based upon the intensity of native signal determined by electron paramagnetic resonance(EPR).It was estimated that almost all of potassium is kept within the organic phases,while about 30% of sodium is stored in organic phases and the other 70% within mineral phase.The microscopic distributions of potassium in the cross-section and/or surface were revealed by synchrotron radiation Xray fluorescence(SR-XRF) technique.The ratio of potassium to calcium based upon the SR-XRF intensity counter varied considerably from the surface to the interior,and on the surface the highest concentration of potassium was observed in the middle section with decreasing amounts toward the edge.This indirectly documented that exchange of potassium between fluid and bone organic phase maybe occur.
