末次冰期全球气候波动频繁,影响了哺乳动物的演化和迁移历史。汉中天坑群丰富的地质生物记录是重要的古气候、古环境研究材料,并使用石笋重建了秦巴地区末次冰期的季风演化历史。汉中天坑群考察过程中发现的东方剑齿象化石也为认识晚第...末次冰期全球气候波动频繁,影响了哺乳动物的演化和迁移历史。汉中天坑群丰富的地质生物记录是重要的古气候、古环境研究材料,并使用石笋重建了秦巴地区末次冰期的季风演化历史。汉中天坑群考察过程中发现的东方剑齿象化石也为认识晚第四纪古生物演化历史和生态环境响应提供了重要的参考资料。文章对东方剑齿象样品进行铀系(U-Th)和碳十四(14C)测年,并参考化石上结晶的碳酸钙铀系年龄,判断汉中天坑群天星岩东方剑齿象的生存时代约为27.5kyr BP(kyr=千年;BP=Before the present, present定义为1950年)附近MIS3阶段的DO暖事件。结合已有的石笋氧同位素序列和其他的古气候记录,推测MIS3时期汉中地区气候很可能比现代更温暖湿润,剑齿象从北方迁移到秦岭南部并演化为东方剑齿象,而且主要依靠南方广泛而稳定存在的C_(3)植被为食。到末次盛冰期,气候极端寒冷,东方剑齿象灭绝,而亚洲象因为觅食生态灵活存活至今,生存区间退缩到了西南亚热带地区。展开更多
Arid Central Asia(ACA), with its diverse landscapes of high mountains, oases, and deserts, hosted the central routes of the Silk Roads that linked trade centers from East Asia to the eastern Mediterranean.Ecological p...Arid Central Asia(ACA), with its diverse landscapes of high mountains, oases, and deserts, hosted the central routes of the Silk Roads that linked trade centers from East Asia to the eastern Mediterranean.Ecological pockets and ecoclines in ACA are largely determined by local precipitation. However, little research has gone into the effects of hydroclimatic changes on trans-Eurasian cultural exchange. Here,we reconstruct precipitation changes in ACA, covering the mid-late Holocene with a U-Th dated, ~3 a resolution, multi-proxy time series of replicated stalagmites from the southeastern Fergana Valley,Kyrgyzstan. Our data reveal a 640-a megadrought between 5820 and 5180 a BP, which likely impacted cultural development in ACA and impeded the expansion of cultural traits along oasis routes. Instead,it may have diverted the earliest transcontinental exchange along the Eurasian steppe during the 5 th millennium BP. With gradually increasing precipitation after the megadrought, settlement of peoples in the oases and river valleys may have facilitated the opening of the oasis routes, ‘‘prehistoric Silk Roads", of trans-Eurasian exchange. By the 4 th millennium BP, this process may have reshaped cultures across the two continents, laying the foundation for the organized Silk Roads.展开更多
It is conducive to the sustainable development of human beings in karst regions to research the mechanism of karst rocky desertification(KRD)expansion.Whether the large-scale KRD in southwestern China is caused by cli...It is conducive to the sustainable development of human beings in karst regions to research the mechanism of karst rocky desertification(KRD)expansion.Whether the large-scale KRD in southwestern China is caused by climate change or human activities is still controversial.In this study,the evolution of the KRD in southwestern China over the past 2000 years was reconstructed through the high-precisionδ^(13)C record of stalagmites from Shijiangjun(SJJ)Cave,Guizhou Province,China.Theδ^(13)C of the stalagmites from SJJ Cave exhibited heavy values from the Medieval Warm Period(MWP)to the Little Ice Age(LIA).Furthermore,theδ^(13)C records of other stalagmites and tufa from southwestern China also showed the same significant heavy trend.Because the stalagmiteδ^(13)C could record the change of ecological environment,it indicated that the consistent change of the stalagmitesδ^(13)C may record the process of KRD expansion in the karst regions of southwestern China.During the MWP,the stronger Asian summer monsoon and the northward movement of the rain belt led to a dry period in southwestern China and a wet period in northern China.In contrast,it was wet in southwestern China and dry in northern China during the LIA.In addition,after the Jing-Kang event(JK event,AD1127)occurred at the end of the Northern Song dynasty,the political and economic center of China migrated to southern China for the first time,which changed the population distribution pattern of larger population in the north and smaller population in the south.Therefore,the expansion of KRD in southwestern China was exacerbated in the MWP due to the change of climate in southwestern China,the migration of a large number of people,wars,the large-scale reclamation of arable land,and the cultivation of large areas of crops.展开更多
文摘末次冰期全球气候波动频繁,影响了哺乳动物的演化和迁移历史。汉中天坑群丰富的地质生物记录是重要的古气候、古环境研究材料,并使用石笋重建了秦巴地区末次冰期的季风演化历史。汉中天坑群考察过程中发现的东方剑齿象化石也为认识晚第四纪古生物演化历史和生态环境响应提供了重要的参考资料。文章对东方剑齿象样品进行铀系(U-Th)和碳十四(14C)测年,并参考化石上结晶的碳酸钙铀系年龄,判断汉中天坑群天星岩东方剑齿象的生存时代约为27.5kyr BP(kyr=千年;BP=Before the present, present定义为1950年)附近MIS3阶段的DO暖事件。结合已有的石笋氧同位素序列和其他的古气候记录,推测MIS3时期汉中地区气候很可能比现代更温暖湿润,剑齿象从北方迁移到秦岭南部并演化为东方剑齿象,而且主要依靠南方广泛而稳定存在的C_(3)植被为食。到末次盛冰期,气候极端寒冷,东方剑齿象灭绝,而亚洲象因为觅食生态灵活存活至今,生存区间退缩到了西南亚热带地区。
基金supported by the National Key Research and Development Program of China (2018YFA0606400)he Strategic Priority Research Program of Chinese Academy of Sciences (XDB40000000)+5 种基金the 2nd Tibetan Plateau Scientific Expedition and Research (2019QZKK0101)the Youth Innovation Promotion Association of Chinese Academy of Sciences (Y201681)partly supported by the National Natural Science Foundation of China (41888101)the National Social Science Foundation of China (18ZDA172)the National Science Foundation of United States (NSF 1702816, EAR-0908792, and EAR-1211299)a part of the ‘‘Belt & Road” Project of the Institute of Earth Environment, Chinese Academy of Sciences (IEECAS)。
文摘Arid Central Asia(ACA), with its diverse landscapes of high mountains, oases, and deserts, hosted the central routes of the Silk Roads that linked trade centers from East Asia to the eastern Mediterranean.Ecological pockets and ecoclines in ACA are largely determined by local precipitation. However, little research has gone into the effects of hydroclimatic changes on trans-Eurasian cultural exchange. Here,we reconstruct precipitation changes in ACA, covering the mid-late Holocene with a U-Th dated, ~3 a resolution, multi-proxy time series of replicated stalagmites from the southeastern Fergana Valley,Kyrgyzstan. Our data reveal a 640-a megadrought between 5820 and 5180 a BP, which likely impacted cultural development in ACA and impeded the expansion of cultural traits along oasis routes. Instead,it may have diverted the earliest transcontinental exchange along the Eurasian steppe during the 5 th millennium BP. With gradually increasing precipitation after the megadrought, settlement of peoples in the oases and river valleys may have facilitated the opening of the oasis routes, ‘‘prehistoric Silk Roads", of trans-Eurasian exchange. By the 4 th millennium BP, this process may have reshaped cultures across the two continents, laying the foundation for the organized Silk Roads.
基金supported by the National Natural Science Foundation of China(Grant Nos.41772170,42011530078)the Fundamental Research Funds for the Central Universities,China(Grant Nos.XDJK2017A010,XDJK2020D005)to Li T Y+2 种基金the Chongqing Municipal Science and Technology Commission Fellowship Fund(Grant Nos.cstc2019yszx-jcyjX0002,cstc2020yszxjcyjX0006)to Yuan D X,and the Open Project of Guangxi Key Science and Technology Innovation Base on Karst Dynamics(Grant No.KDL&Guangxi 202003)to Li J Y.230Th dating at the High-precision Mass Spectrometry and Environment Change Laboratory(HISPEC),Taiwan University,Chinawas supported by the Science Vanguard Research Program of the Ministry of Science and Technology(Grant No.108-2119-M-002-012)the Higher Education Sprout Project of the Ministry of Education,Taiwan,China(Grant No.108L901001)to Shen C C.This research was also Supported by the China Scholarship Council(CSC)(Grant No.202006990068)to Chen C C.
文摘It is conducive to the sustainable development of human beings in karst regions to research the mechanism of karst rocky desertification(KRD)expansion.Whether the large-scale KRD in southwestern China is caused by climate change or human activities is still controversial.In this study,the evolution of the KRD in southwestern China over the past 2000 years was reconstructed through the high-precisionδ^(13)C record of stalagmites from Shijiangjun(SJJ)Cave,Guizhou Province,China.Theδ^(13)C of the stalagmites from SJJ Cave exhibited heavy values from the Medieval Warm Period(MWP)to the Little Ice Age(LIA).Furthermore,theδ^(13)C records of other stalagmites and tufa from southwestern China also showed the same significant heavy trend.Because the stalagmiteδ^(13)C could record the change of ecological environment,it indicated that the consistent change of the stalagmitesδ^(13)C may record the process of KRD expansion in the karst regions of southwestern China.During the MWP,the stronger Asian summer monsoon and the northward movement of the rain belt led to a dry period in southwestern China and a wet period in northern China.In contrast,it was wet in southwestern China and dry in northern China during the LIA.In addition,after the Jing-Kang event(JK event,AD1127)occurred at the end of the Northern Song dynasty,the political and economic center of China migrated to southern China for the first time,which changed the population distribution pattern of larger population in the north and smaller population in the south.Therefore,the expansion of KRD in southwestern China was exacerbated in the MWP due to the change of climate in southwestern China,the migration of a large number of people,wars,the large-scale reclamation of arable land,and the cultivation of large areas of crops.
