The timing of Palaeolithic human activities in South China is still controversial because of the lack of a reliable chronology of archaeological sites.The Longdengshan Palaeolithic site(LPS),located close to the Wuyi ...The timing of Palaeolithic human activities in South China is still controversial because of the lack of a reliable chronology of archaeological sites.The Longdengshan Palaeolithic site(LPS),located close to the Wuyi Mountain of South China,represents the first discovered and scientifically excavated Middle Palaeolithic site in the Fujian Province.This site is of considerable significance for studying the diffusion and cultural connotation of early Homo sapiens in southern China.In this study,we present optically stimulated luminescence(OSL)ages obtained from medium-grained quartz collected at the LPS.The single-aliquot regenerative-dose measurements of red soil deposits collected at the same site yielded internally and stratigraphically consistent ages and similar errors,indicating a potential ability of the technique,and also reflecting the influence of various sedimentary facies on the test results.Our results indicate that the 38–63µm quartz grains were generally partially-bleached and had large values of over-dispersion in the palaeo-reticulated laterites of west Fujian.Some samples yielded unsatisfactory results,suggesting that the degree of bleaching of diluvial and alluvial deposits should be properly assessed before dating.We did not detect any enrichment/depletion of U,Th and radioactive disequilibrium.The effect of chemical weathering on the dose rate estimation was negligible.Therefore,we used a central age model and the maximum age model to calculate the age of two samples,respectively,and the minimum age model to calculate the ages of the rest of the samples.The OSL ages of the samples ranged from 27.09±2.30 ka to 54.65±7.39 ka for the 38–63µm quartz size fraction,and roughly corresponded to the Marine Isotope Stage 3.In addition,three ages out of five are based on the calculation of minimum ages in this research,which needs to be further verified by other dating methods.展开更多
Cryogenic wedges developed due to very cold,rather arid conditions during the maximum of the last cold event when the drying up of the neighboring China Sea resulted in the failure of the East Asian Monsoon.As the cli...Cryogenic wedges developed due to very cold,rather arid conditions during the maximum of the last cold event when the drying up of the neighboring China Sea resulted in the failure of the East Asian Monsoon.As the climate ameliorated and the Monsoon rains reappeared,ice-wedges developed.Further warming permitted thawing of the ice infillings accompanied by replacement of the ice by sediments partly from the host ground as well as from the surface by wind or sheet wash.In cases of extreme surface water flow on slopes after 10 ka B.P.,small baydjarakhs typically c.50 cm high developed,only to have the resulting hollows infilled by sediments carried by wind and/or sheet wash.These shallow structures form a network on top of many of the cryogenic wedges.This complex history makes dating the ages of the wedges difficult using OSL methodology.Unfortunately,past field work ignored the problem of the angle of the cut face to the direction of the wedge infilling when sampling the contents of the narrow wedges,resulting in potential contamination of the samples with the host sediment.Sampling of the larger deposits should be alright,but the likelihood of contamination makes the interpretation of the resulting OSL dates from the narrow wedges questionable.Primary wedges consisting of primary mineral infillings should still have similar OSL dates with depth for a given wedge,but the distinction between ice-wedge infillings and soil wedges is difficult since both can exhibit older dates of the infillings with depth.The available data suggests that ice-wedges were significantly more common than sediment-filled primary wedges.A protocol to avoid having to obtain large numbers of OSL dates by more careful field sampling and the use of grain size determinations is provided in the Appendix.展开更多
哈尔滨黄土位于欧亚黄土带最东端,对揭示亚洲内陆干旱化东向扩展进程具有重要意义。早先的哈尔滨黄土堆积的底界年龄与亚洲干旱化进程相矛盾,这限制了对松嫩平原气候—地貌—构造—水系演化等耦合过程的理解。论文对哈尔滨荒山黄土剖面...哈尔滨黄土位于欧亚黄土带最东端,对揭示亚洲内陆干旱化东向扩展进程具有重要意义。早先的哈尔滨黄土堆积的底界年龄与亚洲干旱化进程相矛盾,这限制了对松嫩平原气候—地貌—构造—水系演化等耦合过程的理解。论文对哈尔滨荒山黄土剖面进行较高分辨率的14C、OSL和ESR测年,并通过实际测年结果拟合外推证实了所建立年代学框架的合理性,得出以下结论:①基于贝叶斯模型计算得出哈尔滨黄土底界年龄为170 ka;②哈尔滨黄土位于东亚季风气候区的北缘,代表了欧亚黄土带最东端的风尘堆积,哈尔滨黄土开始堆积指示其源区已发生明显干旱化,即松嫩沙地的形成不晚于170 ka BP,亚洲内陆干旱化的东移进程也因此得到进一步证实;③哈尔滨黄土堆积是对松嫩平原气候—构造(松辽分水岭隆升)—水系演化(松花江水系演化和松嫩古湖消亡)等的共同响应,因此,在可靠的年龄框架基础上哈尔滨黄土底界年龄对松辽分水岭的构造隆升和松花江水系演化的时间具有一定限制作用。展开更多
基金supported by National Natural Science Foundation of China(Grant Nos.41301012,42077407 and 41771020),Natural Science Foundation of Fujian Province,China(Grant No.2020J01185),and the Innovation Research Team Fund of Fujian Normal University(Grant No.IRTL1705).
文摘The timing of Palaeolithic human activities in South China is still controversial because of the lack of a reliable chronology of archaeological sites.The Longdengshan Palaeolithic site(LPS),located close to the Wuyi Mountain of South China,represents the first discovered and scientifically excavated Middle Palaeolithic site in the Fujian Province.This site is of considerable significance for studying the diffusion and cultural connotation of early Homo sapiens in southern China.In this study,we present optically stimulated luminescence(OSL)ages obtained from medium-grained quartz collected at the LPS.The single-aliquot regenerative-dose measurements of red soil deposits collected at the same site yielded internally and stratigraphically consistent ages and similar errors,indicating a potential ability of the technique,and also reflecting the influence of various sedimentary facies on the test results.Our results indicate that the 38–63µm quartz grains were generally partially-bleached and had large values of over-dispersion in the palaeo-reticulated laterites of west Fujian.Some samples yielded unsatisfactory results,suggesting that the degree of bleaching of diluvial and alluvial deposits should be properly assessed before dating.We did not detect any enrichment/depletion of U,Th and radioactive disequilibrium.The effect of chemical weathering on the dose rate estimation was negligible.Therefore,we used a central age model and the maximum age model to calculate the age of two samples,respectively,and the minimum age model to calculate the ages of the rest of the samples.The OSL ages of the samples ranged from 27.09±2.30 ka to 54.65±7.39 ka for the 38–63µm quartz size fraction,and roughly corresponded to the Marine Isotope Stage 3.In addition,three ages out of five are based on the calculation of minimum ages in this research,which needs to be further verified by other dating methods.
文摘Cryogenic wedges developed due to very cold,rather arid conditions during the maximum of the last cold event when the drying up of the neighboring China Sea resulted in the failure of the East Asian Monsoon.As the climate ameliorated and the Monsoon rains reappeared,ice-wedges developed.Further warming permitted thawing of the ice infillings accompanied by replacement of the ice by sediments partly from the host ground as well as from the surface by wind or sheet wash.In cases of extreme surface water flow on slopes after 10 ka B.P.,small baydjarakhs typically c.50 cm high developed,only to have the resulting hollows infilled by sediments carried by wind and/or sheet wash.These shallow structures form a network on top of many of the cryogenic wedges.This complex history makes dating the ages of the wedges difficult using OSL methodology.Unfortunately,past field work ignored the problem of the angle of the cut face to the direction of the wedge infilling when sampling the contents of the narrow wedges,resulting in potential contamination of the samples with the host sediment.Sampling of the larger deposits should be alright,but the likelihood of contamination makes the interpretation of the resulting OSL dates from the narrow wedges questionable.Primary wedges consisting of primary mineral infillings should still have similar OSL dates with depth for a given wedge,but the distinction between ice-wedge infillings and soil wedges is difficult since both can exhibit older dates of the infillings with depth.The available data suggests that ice-wedges were significantly more common than sediment-filled primary wedges.A protocol to avoid having to obtain large numbers of OSL dates by more careful field sampling and the use of grain size determinations is provided in the Appendix.
文摘哈尔滨黄土位于欧亚黄土带最东端,对揭示亚洲内陆干旱化东向扩展进程具有重要意义。早先的哈尔滨黄土堆积的底界年龄与亚洲干旱化进程相矛盾,这限制了对松嫩平原气候—地貌—构造—水系演化等耦合过程的理解。论文对哈尔滨荒山黄土剖面进行较高分辨率的14C、OSL和ESR测年,并通过实际测年结果拟合外推证实了所建立年代学框架的合理性,得出以下结论:①基于贝叶斯模型计算得出哈尔滨黄土底界年龄为170 ka;②哈尔滨黄土位于东亚季风气候区的北缘,代表了欧亚黄土带最东端的风尘堆积,哈尔滨黄土开始堆积指示其源区已发生明显干旱化,即松嫩沙地的形成不晚于170 ka BP,亚洲内陆干旱化的东移进程也因此得到进一步证实;③哈尔滨黄土堆积是对松嫩平原气候—构造(松辽分水岭隆升)—水系演化(松花江水系演化和松嫩古湖消亡)等的共同响应,因此,在可靠的年龄框架基础上哈尔滨黄土底界年龄对松辽分水岭的构造隆升和松花江水系演化的时间具有一定限制作用。
