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1.
Wen, R. L., Xiao, J. L., Chang, Z. G., Zhai, D. Y., Xu, Q. H., Li, Y. C. & Itoh, S. 2009: Holocene precipitation and temperature variations in the East Asian monsoonal margin from pollen data from Hulun Lake in northeastern Inner Mongolia, China. Boreas, 10.1111/j.1502‐3885.2009.00125.x. ISSN 0300‐9483. Quantitative palaeoclimatic reconstruction with the weighted averaging partial least squares method was applied to the pollen profile from Hulun Lake in northeastern Inner Mongolia. The data provide a detailed history of variations in precipitation and temperature over the northeastern margin of the East Asian summer monsoon during the Holocene. A warm and dry climate prevailed over the lake region until c. 8000 cal. BP. During the period c. 8000–4400 cal. BP, precipitation increased markedly and temperature gradually declined. The interval between c. 4400 and 3350 cal. BP was marked by extremely dry and relatively cold conditions. Precipitation recovered from c. 3350 to 1000 cal. BP, with temperatures rising c. 3350–2050 cal. BP and dropping c. 2050–1000 cal. BP. During the last 500 years, the climate of the lake region displayed a general trend of warming and wetting. While Holocene temperature variations in the mid‐high latitude monsoonal margin were controlled by changes in summer solar radiation in the Northern Hemisphere, they could also be related to the strength of the East Asian summer monsoon. The lack of precipitation during the early Holocene could be attributed to the weakened summer monsoon resulting from the existence of remnant ice sheets in the Northern Hemisphere. Changes in the monsoonal precipitation during the middle to late Holocene would have been associated with the ocean–atmosphere interacting processes occurring in the western tropical Pacific.  相似文献   

2.
Zhu, C., Ma, C., Yu, S.-Y., Tang, L., Zhang, W. & Lu, X. 2009: A detailed pollen record of vegetation and climate changes in Central China during the past 16 000 years. Boreas , 10.1111/j.1502-3885.2009.00098.x. ISSN 0300-9483.
Detailed pollen analyses, along with magnetic and loss-on-ignition (LOI) measurements, were conducted on a 3 m long peat sequence recovered from the Dajiuhu Basin, the Shennongjia Mountains in Central China. Ten AMS 14C dates provide a firm age control on this pollen record in terms of vegetation changes governed essentially by the rise and fall of the Asian summer monsoon during the past 16 000 years. Between 16 000 and 12 700 cal. yr BP, pollen assemblages were dominated by coniferous and broad-leaved trees, indicating a mixed forest landscape corresponding to the initial establishment of the monsoonal climate after the Last Glaciation. The progressive increases in percentages of evergreen tree pollen after 12 700 cal. yr BP point to a steady enhancement of the summer monsoon, which was episodically weakened during the Younger Dryas stadial. From 11 000 to 6000 cal. yr BP, values of coniferous and deciduous tree pollen decreased, while evergreen broad-leaved tree pollen increased substantially, implying a stronger than normal monsoonal climate condition corresponding to the Holocene Hypsithermal Interval. A great reduction in the values of evergreen tree pollen at about 4000 cal. yr BP indicates a sudden retreat of the summer monsoon from this area.  相似文献   

3.
The latest Early Oligocene record from the Lanzhou Basin, northeast Tibetan Plateau, presents an opportunity to investigate early stage of the Asian monsoon patterns due to its special location. The record provides insights into the global zonal climate and the development of the non-zonal monsoon system. The study identifies possible links between factors governing the monsoonal patters and paleoaltimetry of the Tibetan Plateau. Sporomorphs results indicate the dominance of arboreal plants (both coniferous and broad-leaved) corresponding to a wetter environment, while xerophytes were rare. Based on the Coexistence Approach (CA), the climate of the Lanzhou Basin is likely to have been similar to that of present-day sites in Southeast China, i.e., characterized by relatively high precipitation and a warm climate. Both qualitative analysis of the sporomorph assemblages and quantitative calculations indicate that monsoons similar to those of the present daywere formed in East Asia and reached the Lanzhou region in inner Asia. High percentages of Picea, generally associated with the relatively high topography of the NE Tibetan Plateau, correlate well with the high paleoaltimetry of the main Tibetan Plateau during the Oligocene. Thus, the East Asian monsoon during this time can be closely linked to an uplifted Tibetan Plateau, following modeled relationships between the Tibetan Plateau and monsoon patterns. However, we believe such high precipitation may have mainly resulted from the orographic barrier, rather than being driven by zonal climate factors. Further investigation into the extent of, and controls on, the region of high precipitation should help clarify the role of these processes.  相似文献   

4.
伍婧  刘强 《地球科学》2012,37(5):947-954
地处季风/非季风影响过渡地带的月亮湖是大兴安岭中段阿尔山-柴河火山区中的一个火山口湖.其长8.86 m的沉积岩心孢粉记录, 揭示了末次冰期晚期以来的古植被演化和古气候变化历史: 20.9~18.0 cal. ka B.P.期间研究区的植被为典型草原, 气候寒冷干旱; 18.0~15.3 cal. ka B.P.期间研究区的植被为草甸草原, 气候寒冷湿润; 15.3~14.0 cal. ka B.P.期间乔木开始在当地发育, 植被开始由草甸草原向森林草原转变, 气候向较为温暖湿润的方向转变; 14.0~12.8 cal. ka B.P.期间森林草原在温暖湿润的气候影响下, 森林扩张, 草原退缩, 与B?lling-Aller?d暖期相对应; 12.8~11.8 cal. ka B.P.期间草原在寒冷气候下扩张, 可与新仙女木期相对应; 11.8~0.8 cal. ka B.P. 期间在较为温暖的气候条件下, 草原在气候快速变冷事件的影响下发生了多次扩张, 其中, 较为明显的6次气温突降事件分别发生在9.0~8.9, 8.2~7.8, 7.0~6.8, 6.1~5.6, 5.4~5.2, 2.3~1.8 cal. ka B.P..这些快速气候变化事件与全球和区域中其他高分辨率古气候记录具有可比性, 揭示出月亮湖敏感地记录了全球和区域气候的变化, 同时也表明研究区的高分辨率孢粉分析是研究东亚季风强度变化的良好指标.   相似文献   

5.
We present a late glacial pollen record (17,700 to 8500 cal yr BP) from a Lake Naleng sediment core. Lake Naleng is located on the southeastern Tibetan Plateau (31.10°N 99.75°E, 4200 m) along the upper tree-line. Variations in the summer monsoon are evident from shifts in vegetation that correspond to late glacial climate trends from other monsoon-sensitive regions. Alpine steppe was recorded between 17,700 and 14,800 cal yr BP, indicating low effective moisture at the study site. Expansion of alpine meadows followed by advances in the position of tree-line around Lake Naleng suggest that climate became warmer and wetter between ∼ 14,800 and 12,500 cal yr BP, probably representing an enhancement of the Asian monsoon. Climatic cooling and reduced effective moisture are inferred from multivariate analysis and the upward retreat of tree-line between ∼ 12,500 and 11,700 cal yr BP. The timing and nature of these shifts to warm, wet and then cold, dry climatic conditions suggest that they correspond to the Bølling/Allerød and Younger Dryas intervals. Abies-Betula forests, representing warm and moist conditions, spread during the early Holocene.  相似文献   

6.
Quantitative information on vegetation and climate history from the late glacial-Holocene on the Tibetan Plateau is extremely rare. Here, we present palynological results of a 4.30-m-long sediment record collected from Koucha Lake in the Bayan Har Mountains, northeastern Tibetan Plateau. Vegetation change has been traced by biomisation, ordination of pollen data, and calculation of pollen ratios. The application of a pollen-climate calibration set from the eastern Tibetan Plateau to Koucha Lake pollen spectra yielded quantitative climate information. The area was covered by alpine desert/steppe, characteristic of a cold and dry climate (with 50% less precipitation than today) between 16,700 and 14,600 cal yr BP. Steppe vegetation, warm (∼ 1°C higher than today) and wet conditions prevailed between 14,600 and 6600 cal yr BP. These findings contradict evidence from other monsoon-influenced areas of Asia, where the early Holocene is thought to have been moist. Low effective moisture on the northeastern Tibetan Plateau was likely due to high temperature and evaporation, even though precipitation levels may have been similar to present-day values. The vegetation changed to tundra around 6600 cal yr BP, indicating that wet and cool climate conditions occurred on the northeastern Tibetan Plateau during the second half of the Holocene.  相似文献   

7.
This article examines Holocene environmental change in Zhuye Lake in the marginal area of the Asian monsoon, NW China. Holocene environment records were obtained for the QTH01 and QTH02 sections in Zhuye Lake. The fluctuations in grain size, pollen, total organic carbon content and C/N ratios record notable environmental variation. The early Holocene (11.0 to 7.4 cal. kyr BP) was relatively arid, while vegetation coverage was sparse and primary productivity low. The optimal environment prevailed during the mid-Holocene (7.4 to 4.7 cal. kyr BP). Vegetation coverage was the densest and primary productivity the highest during the mid-Holocene. During the late Holocene (4.7 to 0 cal. kyr BP), the environment became arid, as shown by low lake level and sparse vegetation coverage. After 1.6 cal. kyr BP another strong aridification occurred. In this area, the environment was likely to have been influenced by both the Westerlies and the East Asian monsoon during the Holocene. During the early Holocene, the relatively arid environment lay in the background of the increasing East Asian monsoon and dry westerly wind. During the mid-Holocene, central Asia was controlled by the humid Westerlies, while a strong East Asian monsoon prevailed in Central China. The mid-Holocene optimum in this area benefited from an expanded East Asian monsoon and the humid Westerlies. Weakening of the East Asian monsoon caused aridification of the environment during the late Holocene. Intensification of this aridification after 1.6 cal. kyr BP might be correlated with appearance of the arid environments in the Westerly domain after ∼1.5 cal. kyr BP. These arid conditions might be affected by the decreased moisture content of the Westerlies.  相似文献   

8.
In the East Asian monsoon region,eolian deposits widely distributed in the middle-lower reaches of the Yantgze River are among the best materials available for studies on Quaternary climate change in the subtropical zone of Southern China.Typical eolian deposits in this region include upper Xiashu Loess(XL) and underlying Vermiculated Red Soil(VRS) layers.In this paper,chronological and paleoclimatic studies are conducted on an eolian deposit sequence near Jiujiang(JJ) city in northern Jiangxi province.A magnetostratigraphic study,combined with optically stimulated luminescence(OSL) dating,is conducted on the JJ section and provides further evidence that eolian deposits in the middle-lower reaches of the Yangtze River have been formed since the late Early Pleistocene,and that the boundary age between the XL and VRS layers is about 300-400 kaBP.In grain-size records of the JJ section,the median grain-size and content of the 30 μm size fraction increase sharply after 300-400 kaBP,representing an East Asian winter monsoon intensification event.Further pollen analysis reveals differing pollen assemblages before and after 300-400 kaBP:there is an evident increase in plants adapted to grow in a warm humid environment after 300-400 kaBP,implying an increase in precipitation caused by intensification of the East Asian summer monsoon.Global ice volume and uplift of the Tibet Plateau(TP) are regarded as crucial factors influencing variations of the East Asian monsoon on a long-term scale.The deep-sea δ~(18)O record,which reflects variations in global ice volume,shows no obvious change after 300-400 kaBP.Moreover,the influence of global ice volume changes on the East Asian summer and winter monsoons is inverse;the global ice volume increase(decrease) implies a strengthened(weakened) winter monsoon and weakened(strengthened) summer monsoon.We therefore interpret the coupled intensifications of the East Asian summer and winter monsoons at about 300-400 kaBP to the uplift of the TP in the Middle Pleistocene.This climate event is also documented in eolian deposits from the southern margin of the Chinese Loess Plateau(CLP) and from the desert-loess transitional belt.However,it is not recorded in the loess-paleosol sequences from the central part of the CLP,thereby indicating differing climate responses to TP uplift in different regions,which requires further study.  相似文献   

9.
河北坝上地区位于东亚季风边缘区和农牧交错带,季风强弱的变化深刻影响着该地区人类文明的发展.为了重建河北坝上地区中-晚全新世以来的气候演化过程,剖析气候变化与人类文明发展的关系,以坝上地区安固里淖湖为研究对象,通过对该湖沉积剖面植硅体的分析,并结合孢粉组合特征,恢复了安固里淖地区5 000 cal.a BP以来的气候演变历史.结果显示,在千年尺度上该区域气候总体呈冷干趋势,但在5 030~3 070 cal.a BP时期气候相对湿润,千年尺度上气候的变化主要受控于北半球太阳辐射量的变化.在百年尺度上安固里淖地区经历了7次冷干事件,分别发生于4 500 cal.a BP、4 100~3 800 cal.a BP、3 500 cal.a BP、3 000 cal.a BP、2 100 cal.a BP、1 100 cal.a BP和800~270 cal.a BP左右,这7次冷干事件对应于东亚季风减弱阶段,主要受到了北半球高纬气候和太阳活动的共同影响.该区人类文明的演化敏感响应于气候变化,气候温湿期以农业文明为主,气候冷干期以草原文明为主.   相似文献   

10.
A pollen record from Huguangyan Maar Lake documents regional palaeovegetation and palaeoclimate changes in southern China over the last 30 000 years. Huguangyan Maar Lake is located close to the South China Sea (SCS) coastline and is influenced by the East Asian Monsoon (EAM). The pollen assemblages show a succession of vegetation and climate changes. During the Last Glaciation, 30–15.8 cal. ka BP, the Huguangyan area was dominated by subtropical evergreen‐deciduous forest with grassland surrounding the lake, indicating a colder and drier climate than today. During 15.8–11 cal. ka BP, the study area experienced several climatic fluctuations. From 11 to 2 cal. ka BP, the climate shifted to warmer and wetter conditions. After the Holocene Optimum in the early Holocene, the temperature and precipitation decreased. The sediment record of the last 2000 years cannot be used to interpret natural palaeoclimate changes due to the intense anthropogenic influences. Overall, however, the Huguangyan pollen archive highlights the rapid responses of subtropical vegetation to insolation changes in southern China.  相似文献   

11.
头社盆地位于中国台湾省中部,东亚季风区的最前沿,对东亚季风的响应十分敏感,研究其中晚全新世以来古植被、重建古气候序列,探讨其气候与东亚夏季风的关系具有重要的科学意义。文章对头社盆地泥炭—湖泊沉积的AMS14C测年、体积磁化率测试的基础上,基于孢粉记录,重建晚全新世来植被变化,恢复古气候。结果表明全新世中晚期以来分六个阶段：6.2~6.0 cal ka BP,气候凉干,植被类型是亚热带常绿阔叶林;6.0~4.0 cal ka BP,气候转暖湿,植被类型为含较多热带成分的亚热带常绿阔叶林;4.0~2.2 cal ka BP,气候相对凉干,植被类型转为亚热带常绿阔叶林;2.2~1.9 cal ka BP,气候又变暖湿;1.9~1.7 cal ka BP,气候快速冷干事件,森林退化;1.7~1.3 cal ka BP,气候重转温暖湿润,植被类型为接近现代的沼泽草原。整体上6.2~2.2 cal ka BP的气候变化是由温暖湿润向温凉干燥转变的趋势,这是全新世中晚期以来的太阳辐射量减少所导致的,太阳辐射量的减少导致热带辐合南移,进而导致东亚夏季风减弱,而2.2 cal ka BP之后气候波动较大,可能是在东亚夏季风减弱的背景下,ENSO活动加强与人类活动的干扰下耦合的结果。  相似文献   

12.
Fluctuations in climatic proxies of the Milanggouwan section in the Salawusu River valley of the Ordos Plateau (Inner Mongolia, China) during Marine Isotope stage 3 (MIS 3) coincide well with sedimentary cycles for palaeo‐mobile dune sands alternating with fluvial–lacustrine facies and palaeosols. We compared the palaeo‐mobile dune sands with modern mobile dune sands (products of a cold and dry climate dominated by the East Asian winter monsoon), whereas the fluvial–lacustrine facies and palaeosols were controlled by a wet–warm climate similar to that of the East Asian summer monsoon. The MIS 3 climate of the Salawusu River valley appears to have experienced at least nine wet–warm and ten cold–dry fluctuations, divided into five stages: MIS 3e (58 900–49500 yr BP), MIS 3d (49 500–40 700 yr BP), MIS 3c (40 700–36 900 yr BP), MIS 3b (36 900–27 000 yr BP) and MIS 3a (27 000–22 300 yr BP). The 19 cold–warm climatic fluctuations corresponded roughly to the GRIP and Guliyan records, and with fluctuations in the North Atlantic climate. Notable peaks in the spectral analysis occurred at 19 500 yr, 1020 yr, 640 yr and 500 yr. Our results show that the millennial–centennial climate was closely related to the relative strengths of East Asian monsoons, which are controlled by the North Atlantic thermohaline circulation, and which is also closely linked to the Sun's precession period. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

13.
Heinrich 1事件是发生于末次冰消期的极端气候突变事件之一,对全球大气环流和陆地生态格局产生了深刻影响.基于对东亚夏季风边缘区最北端呼伦湖 HL08 孔5. 75 m 以上沉积岩芯的 AMS 14C定年技术和 415~275 cm段140个样品的孢粉分析,重建了东亚中高纬地区呼伦湖21500~13000 cal. a B. P.高分辨率植被变化历史,在此基础上揭示了Heinrich 1事件期间呼伦湖区植被响应过程,明确了Heinrich 1事件在东亚中高纬地区的表现特征.结果显示:呼伦湖区Heinrich 1事件发生于16500~15400 cal. a B. P.,以剧烈降温和显著干旱化为表现特征;事件发生期间湖区周围山地发育亚高山草甸,森林植被稀疏;湖盆区域以藜科为主的荒漠草原显著扩张,区域植被盖度降低、生态环境明显恶化;同时,不同植被类型对Heinrich 1事件的响应存在明显差别,亚高山草甸和蒿属为主的典型草原较藜科为主的荒漠草原和桦属为主的落叶阔叶林响应更为快速、敏感.  相似文献   

14.
The Dajiuhu mire deposit is a sensitive archive of palaeoenvironmental evolution in the East Asian monsoon region. The aim of this study of the elemental geochemistry of a sediment core from Dajiuhu was to improve our understanding of the geochemical behaviour of elements in peat deposits, as well as the environmental and climatic history of the East Asian monsoon region since the Late Pleistocene. We conducted a principal components analysis (PCA) on inorganic geochemical data obtained by ICP‐MS and XRFS from a sediment core spanning the last 16 ka. In addition, spectral analysis was applied to the PC1 score profile to test periodicities. The PCA results suggest that variations in elemental concentrations in the Dajiuhu core are controlled by three main factors: input of inorganic mineral matter, effect of biological processes and a combination of changes in redox conditions and biological processes. Interpretation of the data suggests that monsoon precipitation increased, albeit with significant volatility, during the last deglaciation (16.0–11.3 cal. ka BP). The early Holocene (11.3–9.4 cal. ka BP) was a humid period, and was followed by monsoon deterioration in the early stages of the middle Holocene. A warm and wet climate dominated between 7.0 and 4.2 cal. ka BP, correlating with the Holocene Climatic Optimum. After a two‐step decrease in monsoon precipitation, beginning at 4.2 cal. ka BP, the climate became more arid until 0.9 cal. ka BP, after which humidity once again increased. The spectral analysis revealed statistically significant periodicities of approximately 1480, 360, 316, 204 and 188 years, indicating solar forcing for the East Asian monsoon evolution over millennial to centennial time scales and a link between the East Asian monsoon and North Atlantic climate.  相似文献   

15.
Records of past vegetation and fire history can be complicated by changes in the depositional environment of a sampling location. However, these changes can alternatively be used as a measure of climate variability. Our study site, ca. 18.0 cal. ka BP record from Little Brooklyn Lake, Wyoming, located near the crest of the Snowy Range, records three moisture states. Initially, the lake was likely a glacier‐fed pond indicated by the presence of Pediastrum algae colonies. Around 13.0 cal. ka BP this pond transitioned to a meadow environment, suggested by the loss of Pediastrum algae colonies and slow sedimentation rates. Meadow conditions were maintained until ca. 5.0 cal. ka BP when Pediastrum algae colony abundance increased,indicating the formation of a shallow lake. From 18.0 to ca. 5.0 cal. ka BP, the pollen record is suggestive of alpine vegetation conditions with relatively high spruce and herbaceous taxa. Low charcoal influx also characterizes the period between 18.0 and 5.0 cal. ka BP. After 5.0 cal. ka BP, the coincidence of the formation of shallow lake and pollen data, indicating a shift to a spruce and fir forest, suggests an increase in effective moisture. Fire remained rare in this basin over the entire record, however, once the lake established sedimentation rates and charcoal influx increased. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

16.
《Quaternary Research》2014,81(3):500-507
We analyzed climate proxies from loessic-soil sections of the southern Chinese Loess Plateau. The early Holocene paleosol, S0, is 3.2 m thick and contains six sub-soil units. Co-eval soils from the central Loess Plateau are thinner (~ 1 m). Consequently higher-resolution stratigraphic analyses can be made on our new sections and provide more insight into Holocene temporal variation of the East Asian monsoon. Both summer and winter monsoon evolution signals are recorded in the same sections, enabling the study of phase relationships between the signals. Our analyses consist of (i) measurements of magnetic properties sensitive to the production of fine-grained magnetic minerals which reflect precipitation intensity and summer monsoon strength; and (ii) grain-size analyses which reflect winter monsoon strength. Our results indicate that the Holocene precipitation maximum occurred in the mid-Holocene, ~ 7.8–3.5 cal ka BP, with an arid interval at 6.3–5.3 cal ka BP. The winter monsoon intensity declined to a minimum during 5.0–3.4 cal ka BP. These results suggest that the East Asian summer and winter monsoons were out of phase during the Holocene, possibly due to their different sensitivities to ice and snow coverage at high latitudes and to sea-surface temperature at low latitudes.  相似文献   

17.
The siliciclastic sediments of the uppermost section of 185 mcd(meters composite depth) from ODP Site 1146 on the northern continental slope of the South China Sea(SCS) were partitioned according to their sources using end-member modeling on grain-size data. The goal was to evaluate the evolution of the East Asian monsoon over the past 2 million years. The siliciclastic sediments were described as hybrids of four end-members, EM1, EM2, EM3, and EM4, with modal grain sizes of 8–22 μm, 2–8 μm, 31–125 μm, and 4–11 μm, respectively. EM1 and EM3 are interpreted as eolian dust and EM2 and EM4 as fluvial mud. The ratio of eolian dust to fluvial mud((EM1+EM3)/(EM2+EM4)) is regarded as an indicator of the East Asian monsoon. The variation in this ratio not only shows periodical oscillations consistent with oxygen isotope stages, but also exhibits a phased increasing trend corresponding with the phased uplifts of the Tibetan Plateau, indicating that the evolution of the East Asian Monsoon was controlled not only by glacial-interglacial cycles, but also by the phased uplifts of the Tibetan Plateau during the Quaternary.  相似文献   

18.
Zhuyeze palaeolake is a terminal lake situated in the arid northern China in the East Asian monsoon margin. In order to examine the Holocene palaeoclimatic change in the East Asian monsoon margin, Qingtu Lake section (QTL) from Zhuyeze palaeolake is sampled in high resolution. Palaeoclimatic proxies such as grain size, carbonate, TOC, C/N and δ13C of organic matter, were analyzed; eleven 14C samples and six optically stimulated luminescence (OSL) samples were dated to provide chronological control. We also investigated the geomorphic features of lake shorelines in this area. The results show that the climate was warm and dry in early-Holocene (9.5-7.0 cal ka BP), cool and humid in mid-Holocene (7.0-4.8 cal ka BP), and increasingly drier in late-Holocene (since 4.8 cal ka BP). Comparisons of our records with other records in adjacent areas, as well as with the records in the Asian monsoon areas, suggested that changes in effective moisture was synchronous in East Asian monsoon marginal zone (i.e. the pattern of dry early-Holocene, humid mid-Holocene, and aridity-increasing late-Holocene), and that the moisture optimum during the Holocene was out-of-phase between Asian monsoon margin and Asian monsoonal dominated region, possibly due to the high temperature at that time.  相似文献   

19.
青藏高原现代表土中冷杉和云杉花粉的空间分布   总被引：25，自引：9，他引：16  
文章通过对青藏高原北纬25°～45°,东经75°～106°范围内海拔1000～5700m的地区所采集的598个表土样品的孢粉分析,研究了现代表土中冷杉和云杉花粉的分布与植被、气候和海拔之间的关系。表土样品中冷杉和云杉花粉高含量范围对应着青藏高原南部和东部山地暗针叶林分布区,花粉等值线图较准确地反映了冷杉和云杉的丰富程度及其与植被、环境的关系;冷杉和云杉花粉百分含量随海拔和气候梯度变化表现出单峰分布模式,冷杉和云杉花粉百分含量大于20%的最适宜海拔高度是2500～4000m,最高含量中心限制在海拔3200m左右、年均温2～3℃范围内;较高的花粉百分含量带出现在年均温0～8℃、年均降水量400～850mm的区域。结果显示了青藏高原现代冷杉和云杉花粉的空间分布与植被、气候、海拔的空间变化之间很好的相关性,为利用花粉资料进行青藏高原地区的古气候重建提供了有益的资料  相似文献   

20.
REORGANIZATION OF THE ASIAN MONSOON SYSTEM AT ABOUT 2.6 Ma AGO AND ITS IMPLICATIONS FOR THE RISING OF THE TIBETAN PLATEAUheChineseResearchFoundation(KZ 951 A1 2 0 4 )  相似文献   

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