雷州半岛地处热带北缘,受东亚季风影响强烈。以取自雷州半岛北部下录地区的埋藏泥炭沉积作为研究材料,测试分析了该岩心的汞浓度及其分布情况,将测试结果与其他气候环境代用指标如孢粉、炭屑、烧失量(LOI)以及有机碳同位素(δ^(13)C_(or...雷州半岛地处热带北缘,受东亚季风影响强烈。以取自雷州半岛北部下录地区的埋藏泥炭沉积作为研究材料,测试分析了该岩心的汞浓度及其分布情况,将测试结果与其他气候环境代用指标如孢粉、炭屑、烧失量(LOI)以及有机碳同位素(δ^(13)C_(org))等进行对比分析,讨论自MIS(Marine Isotope Stages)-3晚期(约40 cal ka B.P.)至全新世早期(约6.9 cal ka B.P.)区域气候与环境变化影响下的汞沉积过程及可能的影响机制。结果显示:近4万年以来,沉积物的汞浓度与乔木类孢粉浓度的变化较吻合,两者之间显示出较高的相关性,揭示了晚更新世晚期以来,森林群落作为重要的地表汞库,在地区汞沉积过程中起到固定、储存和传输作用。此外,汞浓度与岩心中炭屑沉积通量(指示了区域性野火发生状况)的变化存在相反趋势,反映了区域性野火活动对地表植被以及土壤有机质的焚毁破坏,造成地表汞向大气的释放,不利于汞在地表和沉积物中的沉积与保存。对比不同区域的汞沉积记录发现,晚更新世晚期以来,下录泥炭汞浓度记录与全球其他地区汞记录、粉尘记录等具有较高的相似度,特别是MIS-2时期均存在明显峰值,反映了全球气候变化影响下,大气粉尘沉降对地表汞的输送和沉积具有较大贡献。展开更多
The toxic heavy metal mercury(Hg)has significantly enhanced the global Hg cycle influenced by human activities over the last century.In this study,we presented a high-resolution Hg deposition history between∼1780 and...The toxic heavy metal mercury(Hg)has significantly enhanced the global Hg cycle influenced by human activities over the last century.In this study,we presented a high-resolution Hg deposition history between∼1780 and 2015 AD in a sediment core from Xincun Lagoon,located in the southeastern Hainan Island,South China,and analyzed it in conjunction with geochemical elements,grain-size distribution,organic matter,and HYSPLIT backward trajectory simulation.The objective was to investigate the influencing factors affecting historical Hg deposition in relatively remote regions and assess the extent of the effects of natural background and human activities.The results showed that the Hg in the sediment was deposited primarily through atmospheric deposition,which was closely related to regional and even global human activities.Anthropogenic Hg contamination increased gradually from the 1830s to 1850s,possibly due to Hg emissions from Opium Wars I and II occurring in southeastern China.High broad peaks of anthropogenic Hg were observed during the 1910s to 1950s and in the 1980s,likely associated with the two world wars and modern Chinese wars.In addition,a further sharp increase in anthropogenic Hg from the mid-1970s to the present occurred,likely originating from the intense industrial activities in China triggered by the reform and opening-up policy of China in 1978 and some countries in Southeast Asia.展开更多
A 350-cm-long sediment core sequence from Dahu Swamp situated in the eastern Nanling Mountains was selected for high-resolution paleoclimatic reconstruction since the Late Glacial period. The multi-proxy records of th...A 350-cm-long sediment core sequence from Dahu Swamp situated in the eastern Nanling Mountains was selected for high-resolution paleoclimatic reconstruction since the Late Glacial period. The multi-proxy records of this paper reveal several evidently dry and cold events that may coincide with the Oldest Dryas, the Older Dryas, the Younger Dryas in the late deglacial period. Two relatively wetter and warmer phases occurred in ca. 15,000-14,400 cal yr B.P. and 13,500-12,800 cal yr B.P. respectively may correspond to the Boiling and Allerod warming events. The Younger Dryas event （ca. 12,800-11,500 cal yr B.P.） revealed by multi-proxies was characterized by relatively colder and drier climate. A warmer and wetter climate, occurred in ca. 10,000~5000 cal yr B.P., was consistent with the Holoeene Optimum, which coincided with the maximum Northern Hemisphere insolation. The ＂8.2kyr cool event＂ and even the ＂8.8kyr cool event＂ were indicated as well from our sediment core. A dry mid-Holocene period （ca. 60000 3000 cal yr B.P.） indicated by multi-proxies does not follow the traditional concept of the wet mid-Holocene conditions observed in other regions in China.展开更多
Study results in this paper have indicated that the Holocene climate in Xinjiang, Northwestem China has been alternating between wet and dry conditions, and was punctuated with a series of abrupt climate shifts. A sed...Study results in this paper have indicated that the Holocene climate in Xinjiang, Northwestem China has been alternating between wet and dry conditions, and was punctuated with a series of abrupt climate shifts. A sediment core taken from Barkol Lake in the northern Xinjiang of Northwest China was analyzed at 1 cm interval for grain-size distribution. Abrupt climate shifts revealed by the grain-size proxy occurred at ca 1.4, 3.0, 4.3, 5.6, 8.0 cal kyr B.E, which were well correlated to both the abrupt shifts recorded in the North Atlantic Ocean （NAO） and the Holocene sea surface temperature （SST） cooling events in the Arabian Ocean. The correlation indicated that the climatic changes in the extreme arid Northwest China were associated with the NAO, probably via the North Atlantic Oscillation-affected westerly winds. The strength and position of westerly winds probably modulated the Siberian-Mongolian high- pressure system （winter monsoon）, and played an important role in climate change of Northwest China. Moreover, an evident drought interval during the middle Holocene was also revealed by grain-size proxy.展开更多
文摘雷州半岛地处热带北缘,受东亚季风影响强烈。以取自雷州半岛北部下录地区的埋藏泥炭沉积作为研究材料,测试分析了该岩心的汞浓度及其分布情况,将测试结果与其他气候环境代用指标如孢粉、炭屑、烧失量(LOI)以及有机碳同位素(δ^(13)C_(org))等进行对比分析,讨论自MIS(Marine Isotope Stages)-3晚期(约40 cal ka B.P.)至全新世早期(约6.9 cal ka B.P.)区域气候与环境变化影响下的汞沉积过程及可能的影响机制。结果显示:近4万年以来,沉积物的汞浓度与乔木类孢粉浓度的变化较吻合,两者之间显示出较高的相关性,揭示了晚更新世晚期以来,森林群落作为重要的地表汞库,在地区汞沉积过程中起到固定、储存和传输作用。此外,汞浓度与岩心中炭屑沉积通量(指示了区域性野火发生状况)的变化存在相反趋势,反映了区域性野火活动对地表植被以及土壤有机质的焚毁破坏,造成地表汞向大气的释放,不利于汞在地表和沉积物中的沉积与保存。对比不同区域的汞沉积记录发现,晚更新世晚期以来,下录泥炭汞浓度记录与全球其他地区汞记录、粉尘记录等具有较高的相似度,特别是MIS-2时期均存在明显峰值,反映了全球气候变化影响下,大气粉尘沉降对地表汞的输送和沉积具有较大贡献。
基金Under the auspices of the National Natural Science Foundation of China(No.42071108,41671194)。
文摘The toxic heavy metal mercury(Hg)has significantly enhanced the global Hg cycle influenced by human activities over the last century.In this study,we presented a high-resolution Hg deposition history between∼1780 and 2015 AD in a sediment core from Xincun Lagoon,located in the southeastern Hainan Island,South China,and analyzed it in conjunction with geochemical elements,grain-size distribution,organic matter,and HYSPLIT backward trajectory simulation.The objective was to investigate the influencing factors affecting historical Hg deposition in relatively remote regions and assess the extent of the effects of natural background and human activities.The results showed that the Hg in the sediment was deposited primarily through atmospheric deposition,which was closely related to regional and even global human activities.Anthropogenic Hg contamination increased gradually from the 1830s to 1850s,possibly due to Hg emissions from Opium Wars I and II occurring in southeastern China.High broad peaks of anthropogenic Hg were observed during the 1910s to 1950s and in the 1980s,likely associated with the two world wars and modern Chinese wars.In addition,a further sharp increase in anthropogenic Hg from the mid-1970s to the present occurred,likely originating from the intense industrial activities in China triggered by the reform and opening-up policy of China in 1978 and some countries in Southeast Asia.
基金Under the auspices of National Natural Science Foundation of China (No. 40671189)Natural Science Foundation of Guangdong Province (No. 8151063101000044, 06025042)the Fok Ying Tung Education Foundation (No. 91021)
文摘A 350-cm-long sediment core sequence from Dahu Swamp situated in the eastern Nanling Mountains was selected for high-resolution paleoclimatic reconstruction since the Late Glacial period. The multi-proxy records of this paper reveal several evidently dry and cold events that may coincide with the Oldest Dryas, the Older Dryas, the Younger Dryas in the late deglacial period. Two relatively wetter and warmer phases occurred in ca. 15,000-14,400 cal yr B.P. and 13,500-12,800 cal yr B.P. respectively may correspond to the Boiling and Allerod warming events. The Younger Dryas event （ca. 12,800-11,500 cal yr B.P.） revealed by multi-proxies was characterized by relatively colder and drier climate. A warmer and wetter climate, occurred in ca. 10,000~5000 cal yr B.P., was consistent with the Holoeene Optimum, which coincided with the maximum Northern Hemisphere insolation. The ＂8.2kyr cool event＂ and even the ＂8.8kyr cool event＂ were indicated as well from our sediment core. A dry mid-Holocene period （ca. 60000 3000 cal yr B.P.） indicated by multi-proxies does not follow the traditional concept of the wet mid-Holocene conditions observed in other regions in China.
基金Under the auspices of National Natural Science Foundation of China (No. 49761007)Open Foundation of National Laboratory of Western China’s Environmental Systems,Lanzhou University
文摘Study results in this paper have indicated that the Holocene climate in Xinjiang, Northwestem China has been alternating between wet and dry conditions, and was punctuated with a series of abrupt climate shifts. A sediment core taken from Barkol Lake in the northern Xinjiang of Northwest China was analyzed at 1 cm interval for grain-size distribution. Abrupt climate shifts revealed by the grain-size proxy occurred at ca 1.4, 3.0, 4.3, 5.6, 8.0 cal kyr B.E, which were well correlated to both the abrupt shifts recorded in the North Atlantic Ocean （NAO） and the Holocene sea surface temperature （SST） cooling events in the Arabian Ocean. The correlation indicated that the climatic changes in the extreme arid Northwest China were associated with the NAO, probably via the North Atlantic Oscillation-affected westerly winds. The strength and position of westerly winds probably modulated the Siberian-Mongolian high- pressure system （winter monsoon）, and played an important role in climate change of Northwest China. Moreover, an evident drought interval during the middle Holocene was also revealed by grain-size proxy.
