根据一个泥炭剖面高分辨率花粉资料序列,初步重建了科尔沁沙地麦里地区晚全新世的植被演化过程。在3100 a BP以前,该地以固定沙丘上生长的蒙古栎(Quercus mongolica Fisch.)等阔叶疏林为主;以后随着半固定沙丘和流动沙丘增多,蒿属(Artem...根据一个泥炭剖面高分辨率花粉资料序列,初步重建了科尔沁沙地麦里地区晚全新世的植被演化过程。在3100 a BP以前,该地以固定沙丘上生长的蒙古栎(Quercus mongolica Fisch.)等阔叶疏林为主;以后随着半固定沙丘和流动沙丘增多,蒿属(Artemisia L.)和藜科等草本植物逐渐增加,而固定沙丘上的阔叶树则趋于减少。在1000～660 a BP期间,麦里地区几乎所有沙丘植物都经历了繁盛生长,蒙古栎种群的扩大尤其显著。3100 a BP以来植被和沙丘的演化可能同人类活动影响有直接关系,而1000～660 a BP期间的植物繁盛则由生长季雨量增加引起。花粉统计分析还表明,在森林草原等生态过渡带,花粉浓度和花粉沉积率比花粉百分比更好地指示了植被演化过程。展开更多
Environmentally sensitive grain-size component (ESGSC) extracted from grain-size data of a sediment core B2, which were retrieved from mud area southwest off Cheju Island (MACI), East China Sea (ECS), can be used to i...Environmentally sensitive grain-size component (ESGSC) extracted from grain-size data of a sediment core B2, which were retrieved from mud area southwest off Cheju Island (MACI), East China Sea (ECS), can be used to indicate the variations of East Asia Winter Monsoon (EAWM), with high (low) content/mean-size of ESGCS denote to strong (weak) EAWM. Combined with AMS14C datings core B2 provides a continuous high-resolution record of EAWM changes over the past 2300 years, with an average resolution of 13 years. The results show that the variations of EAWM are con-sistent with temperature changes inferred from historical documents in eastern China over the past 2300 years, from which four climate stages may be identified. In stages before 1900 aBP (50 AD) and 1450―780 aBP (50―1170 AD) the EAWM were comparatively weak, corresponding to warm climate periods in eastern China, respectively. And in stages of 1900―1450 aBP (50―500 AD) and 780―219 aBP (1170―1731 AD) the EAWM were strongly developed, which correspond well to climate changes of two cold periods in eastern China. It is also shown from this study that the stage at 780―219 aBP (1170―1731 AD) was the coldest climate period during the last 2300 years and could be, therefore, related to the Little Ice Age (LIA). Climatic fluctuations appeared obviously in all the four stages, and two climate events of abrupt changes from warm to cold occurred at around 1900 aBP (50 AD) and 780 aBP (1170 AD), of which the latter is probably related to globe-scale changes of atmospheric circulation at that time.展开更多
对天目山千亩田2个泥炭剖面的研究显示，样品中Rb和Sr含量变化呈现出较好的正相关性， Rb/Sr比值与总有机碳含量（TOC）、烧失量和腐殖化度等指标有很好的相关性。Rb/Sr比值和Rb、Sr含量对古降水有指示意义，三者结合可用来重建过去气...对天目山千亩田2个泥炭剖面的研究显示，样品中Rb和Sr含量变化呈现出较好的正相关性， Rb/Sr比值与总有机碳含量（TOC）、烧失量和腐殖化度等指标有很好的相关性。Rb/Sr比值和Rb、Sr含量对古降水有指示意义，三者结合可用来重建过去气候的干湿变化。千亩田泥炭剖面Rb/Sr比值和Rb、Sr含量详细记录了晚全新世以来的气候变化，表明其大体存在3个阶段：4.1-3.2 cal. ka B.P.，季风降水出现大幅下降，气候向干旱演变；3.2-1.2 cal. ka B.P.，气候干冷，且有频繁波动；1.2 cal. ka B.P.以来，气候呈现出向湿润变化的趋势，但伴有大幅波动，其中包含了1.2-0.9 cal. ka B.P.的中世纪暖期暖干气候以及0.6-0.3 cal. ka B.P.的明清小冰期冷湿气候。千亩田泥炭Rb/Sr比值和Rb、Sr含量记录的气候变化与东亚季风区中其他地区的多种高分辨率气候记录具有一致性，表明其共同响应了东亚季风的变迁。展开更多
Cores 255, 170, 17940-2, raised from the Okinawa Trough and South China Sea, have been studied for planktonic foraminifers. Among all the species, Pulleniatina obliquiloculata is shown to be sensitive to winter sea su...Cores 255, 170, 17940-2, raised from the Okinawa Trough and South China Sea, have been studied for planktonic foraminifers. Among all the species, Pulleniatina obliquiloculata is shown to be sensitive to winter sea surface temperature in the late Quaternary in the western Pacific. Its relative abundance fluctuations are significant and correlatable between the cores. The most conspicuous change during Holocene is the P. obliquiloculata minimum zone around 4-2ka B. P., which correlates probably to the neoglacial cooling. The widespread occurrence of this cooling event in the western Pacific suggests that P. obliquiloculata is promising as a paleoceanographic and climatic monitor, possibly important for reconstructing sea-land correlation of climate.展开更多
通过对可可西里库赛湖KS-2006孔矿物组合的分析表明:库赛湖沉积的碳酸盐为以文石为主的自生碳酸盐,其含量的高低能够指示温度的变化;盐类矿物只是在2150 cal aBP以来才出现,表明湖水盐度增高,与此同时,石英含量的持续增高可能同冷干气...通过对可可西里库赛湖KS-2006孔矿物组合的分析表明:库赛湖沉积的碳酸盐为以文石为主的自生碳酸盐,其含量的高低能够指示温度的变化;盐类矿物只是在2150 cal aBP以来才出现,表明湖水盐度增高,与此同时,石英含量的持续增高可能同冷干气候条件下该区风成活动的加强有关.青藏高原北部晚全新世的气候环境演化过程为:3770-2550 cal aBP期间气候条件整体较为温暖;2550-2150 cal aBP期间,气温缓慢下降有变冷的趋势;约2150 cal aBP至今,气候迅速转冷,湖区湿度降低,湖水盐度增高,风成活动加强,但900-700 cal aBP期间,为明显的温暖时期.展开更多
文摘根据一个泥炭剖面高分辨率花粉资料序列,初步重建了科尔沁沙地麦里地区晚全新世的植被演化过程。在3100 a BP以前,该地以固定沙丘上生长的蒙古栎(Quercus mongolica Fisch.)等阔叶疏林为主;以后随着半固定沙丘和流动沙丘增多,蒿属(Artemisia L.)和藜科等草本植物逐渐增加,而固定沙丘上的阔叶树则趋于减少。在1000～660 a BP期间,麦里地区几乎所有沙丘植物都经历了繁盛生长,蒙古栎种群的扩大尤其显著。3100 a BP以来植被和沙丘的演化可能同人类活动影响有直接关系,而1000～660 a BP期间的植物繁盛则由生长季雨量增加引起。花粉统计分析还表明,在森林草原等生态过渡带,花粉浓度和花粉沉积率比花粉百分比更好地指示了植被演化过程。
基金supported by the National Natural Science Foundation of China(Grant Nos.90211022 and 40206007)the Innovation Program of the Chinese Academy of Sciences(Grant No.KZCX3-SW-220).
文摘Environmentally sensitive grain-size component (ESGSC) extracted from grain-size data of a sediment core B2, which were retrieved from mud area southwest off Cheju Island (MACI), East China Sea (ECS), can be used to indicate the variations of East Asia Winter Monsoon (EAWM), with high (low) content/mean-size of ESGCS denote to strong (weak) EAWM. Combined with AMS14C datings core B2 provides a continuous high-resolution record of EAWM changes over the past 2300 years, with an average resolution of 13 years. The results show that the variations of EAWM are con-sistent with temperature changes inferred from historical documents in eastern China over the past 2300 years, from which four climate stages may be identified. In stages before 1900 aBP (50 AD) and 1450―780 aBP (50―1170 AD) the EAWM were comparatively weak, corresponding to warm climate periods in eastern China, respectively. And in stages of 1900―1450 aBP (50―500 AD) and 780―219 aBP (1170―1731 AD) the EAWM were strongly developed, which correspond well to climate changes of two cold periods in eastern China. It is also shown from this study that the stage at 780―219 aBP (1170―1731 AD) was the coldest climate period during the last 2300 years and could be, therefore, related to the Little Ice Age (LIA). Climatic fluctuations appeared obviously in all the four stages, and two climate events of abrupt changes from warm to cold occurred at around 1900 aBP (50 AD) and 780 aBP (1170 AD), of which the latter is probably related to globe-scale changes of atmospheric circulation at that time.
文摘对天目山千亩田2个泥炭剖面的研究显示，样品中Rb和Sr含量变化呈现出较好的正相关性， Rb/Sr比值与总有机碳含量（TOC）、烧失量和腐殖化度等指标有很好的相关性。Rb/Sr比值和Rb、Sr含量对古降水有指示意义，三者结合可用来重建过去气候的干湿变化。千亩田泥炭剖面Rb/Sr比值和Rb、Sr含量详细记录了晚全新世以来的气候变化，表明其大体存在3个阶段：4.1-3.2 cal. ka B.P.，季风降水出现大幅下降，气候向干旱演变；3.2-1.2 cal. ka B.P.，气候干冷，且有频繁波动；1.2 cal. ka B.P.以来，气候呈现出向湿润变化的趋势，但伴有大幅波动，其中包含了1.2-0.9 cal. ka B.P.的中世纪暖期暖干气候以及0.6-0.3 cal. ka B.P.的明清小冰期冷湿气候。千亩田泥炭Rb/Sr比值和Rb、Sr含量记录的气候变化与东亚季风区中其他地区的多种高分辨率气候记录具有一致性，表明其共同响应了东亚季风的变迁。
基金Project supported by the National Natural Science Foundation of China.
文摘Cores 255, 170, 17940-2, raised from the Okinawa Trough and South China Sea, have been studied for planktonic foraminifers. Among all the species, Pulleniatina obliquiloculata is shown to be sensitive to winter sea surface temperature in the late Quaternary in the western Pacific. Its relative abundance fluctuations are significant and correlatable between the cores. The most conspicuous change during Holocene is the P. obliquiloculata minimum zone around 4-2ka B. P., which correlates probably to the neoglacial cooling. The widespread occurrence of this cooling event in the western Pacific suggests that P. obliquiloculata is promising as a paleoceanographic and climatic monitor, possibly important for reconstructing sea-land correlation of climate.
文摘通过对可可西里库赛湖KS-2006孔矿物组合的分析表明:库赛湖沉积的碳酸盐为以文石为主的自生碳酸盐,其含量的高低能够指示温度的变化;盐类矿物只是在2150 cal aBP以来才出现,表明湖水盐度增高,与此同时,石英含量的持续增高可能同冷干气候条件下该区风成活动的加强有关.青藏高原北部晚全新世的气候环境演化过程为:3770-2550 cal aBP期间气候条件整体较为温暖;2550-2150 cal aBP期间,气温缓慢下降有变冷的趋势;约2150 cal aBP至今,气候迅速转冷,湖区湿度降低,湖水盐度增高,风成活动加强,但900-700 cal aBP期间,为明显的温暖时期.
