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1.
In addition to being of interest to ancient Greek and Roman historians, the site of Philippi, NE Greece, has long been noted in Quaternary circles for providing the longest continuous European pollen record, spanning the last one million years. Here the original age model is re-evaluated and a new marine-terrestrial correlation is proposed. An astronomical calibration procedure, based on a correspondence between changes in certain vegetation elements and March and June perihelion configurations, suggests that the base of the sequence extends back to 1.35 million years ago. The revised chronological framework for the Tenaghi Philippon sequence provides an opportunity to examine the long-term behaviour of individual taxa and vegetation trends within the context of global climate changes. Comparisons reveal a close correspondence between the terrestrial and marine records, in terms of orbital and suborbital variability. However, joint time-frequency analysis of the arboreal pollen record shows that the obliquity and eccentricity/precession signals persist into the ‘100-kyr’ and ‘41-kyr’ worlds, respectively, suggesting the operation of additional climate mechanisms that are independent of high-latitude glacial–interglacial effects. Unlike ice core and marine sequences, no change in the magnitude of interglacial tree population expansions is observed after the Mid-Brunhes Event. Instead, the Tenaghi Philippon record suggests a major shift in the vegetational composition of interglacials after MIS 16, with the establishment of forests of reduced diversity and a ‘modern’ appearance.  相似文献   

2.
Pollen analysis of a radiocarbon-dated core from a shallow basin in volcanic hills in eastern Scotland revealed the existence of Late Devensian and Flandrian deposits. Much of the vegetation history of the Flandrian proved to be missing due to a hiatus in the profile. The Late Devensian pollen record included anomalous arboreal taxa of three possible origins: contamination, long-distance wind transport and reworking of interstadial material. Because of lacking information on Late Devensian climates and the location of thermophilous arboreal refugia in Europe a re-examination of supposedly contaminated British Late Devensian pollen records might well be rewarding.  相似文献   

3.
The Meikirch drilling site in the Swiss Midlands north of Bern is re‐interpreted using a combination of sedimentological logging, pollen analyses and luminescence dating. The sedimentary sequence comprises about 70 m of lacustrine deposits, overlain by about 39 m of coarse glacial outwash interpreted to represent at least two independent ice advances. Pollen analyses of the apparently complete limnic sequence reveal a basal late glacial period followed by three warm phases that are interrupted by two stadial periods (Meikirch complex). The warm periods were previously correlated with the Holsteinian and Eemian Interglacials. According to luminescence dating, and with consideration of evidence for Middle Pleistocene climate patterns at other central European sites, a correlation of the Meikirch complex with marine isotope stage (MIS) 7 is now proposed. If this correlation is correct, it implies the presence of three intervals with interglacial character during MIS 7. However, the late Middle Pleistocene vegetational features of the Meikirch complex show significant differences when compared with the pollen record from the Velay region, central France. Possible explanations for this discrepancy are distinct Middle Pleistocene patterns of atmospheric circulation over central Europe and a different distribution of vegetation refugia compared to the Eemian Interglacial and the Holocene. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

4.
The cold intensity of the last glacial stadials corresponding to marine isotope stage (MIS) 5d (or 5b), MIS 4 and MIS 2 in terrestrial East Asia monsoon area is not discussed much due to the paucity of long continuous pollen records. A palynological study of drilling cores from three closely-linked intramontane basins (Toushe, Sun-moon Lake and Yuchi) in central Taiwan provides a history of shifting altitudinal vegetation zones in surrounding mountains during late Quaternary climate changes. By integrating these records, we found that the alpine conifer forest approached its lowest altitude, about 614 m, during the earliest stadial (≒MIS 5d or 5b), and 745 m during the early stadial (≒MIS 4) based on records of Yuchi Basin and Sun-moon Lake. In addition, the pollen records of Toushe Basin and Sun-moon Lake show more temperate conditions for the late stadial (≒MIS 2) than the early stadial (≒MIS 4). This leads to an interpretation of a decreasing intensity of stadials during the last glaciation, which might follow the regional insolation amplitude. Such a decreasing trend in coldness during the last glacial stadials does not exist in the record for the South China Sea which reflects a different sensitivity and response to climatic forcings between terrestrial and marine.  相似文献   

5.
The Middle–Late Pleistocene alluvial and lacustrine succession of Valeriano Creek (southeastern Alpine foothills, 190 m a.s.l.) documents the environmental evolution of the piedmont plain before the onset of the Last Glacial Maximum (LGM). The sedimentary record was investigated by multidisciplinary stratigraphical and sedimentological studies coupled with petrographic and palaeobotanical analysis. A chronology has been provided by luminescence, radiocarbon dating and pollen biochronology. The succession developed at the valley mouth of a small catchment and is confined in the piedmont plain by the alluvial fans of major rivers. The oldest deposits were formed during a cold phase during the late Middle Pleistocene. This part of the piedmont plain was generally stable until Termination II, when it was trenched more than 15 m deep by watercourses. The infilling succession of the trench, mostly by low‐energy alluvial sediments interbedded with mire and peat deposits, documents, for the first time on the southern side of the Alps, the relationships between fluvial activity, vegetation and climate change at the foothills piedmont plain during late Marine Isotope Stage (MIS) 5. The stadial–interstadial climate forcing implies a local reorganisation of fluvial dynamics and of forest composition, although substantial plant cover persisted even during cooler stadials. In accordance with coeval alluvial and speleothem records from the northern side of the Alps, this environmental evolution supports a very restricted Alpine glaciation of the main fluvial catchments of the southeastern Alps during MIS 5a–d. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

6.
黔西高原的长时间序列孢粉记录比较少,限制了对该地区末次冰期晚期古植被及西南季风演化过程和机制的认识。本研究通过对黔西高原一个连续的古湖泊沉积物孢粉记录的分析,并结合AMS14C测年,重建黔西高原末次冰期晚期古植被及西南季风演化。结果表明: 轨道尺度上,MIS3(氧同位素3阶段)中晚期,黔西高原主要为木本、草本植物,喜湿的针叶树种较多,西南季风较强。MIS2(氧同位素2阶段)期间,喜湿的针叶树种减少,而草本、蕨类植物增多,指示气候冷干,西南季风减弱。千年尺度上,黔西高原西南季风响应于北大西洋冰漂碎屑事件及H3(Heninrich 3)、H2(Heninrich 2)和LGM(Last Glacial Maximum)事件,导致西南季风减弱,喜湿的针叶树种减少。通过对比发现,东亚夏季风和西南季风在轨道及千年尺度上协同演化,二者均响应于北半球高纬度太阳辐射变化及北大西洋冰漂碎屑事件。在19~18 cal ka BP,黔西高原经历最冷干气候,西南季风减弱,木本、草本植物近乎消失,而同期东亚夏季风增强,说明西南季风和东亚夏季风在冰后期上存在反相位关系。  相似文献   

7.
It has been hypothesized that refugia of thermophilous tree species were located in Northern Italy very close to the Alps, though, this hypothesis has yet to be tested thoroughly. In contrast to Central and Southern Italy with its relative wealth of data, only a few fragmentary records are currently available from Northern Italy for the last Glacial (Würm, Weichselian). Our new study site Lago della Costa lies adjacent to the catchment of the megafans of the Alpine forelands and the braided rivers of the Northeastern Po Plain that have so far inhibited the recovery of continuous Glacial and Late-Glacial records. We analyze pollen, plant macrofossils, charcoal and ostracods to reconstruct the vegetation, fire and lake history for the period 33,000–16,000 cal. BP. We compare our data with Glacial records from Southern Europe to discuss similarities and dissimilarities between these potential refugial areas. A comparison with independent paleoclimatic proxies allows to assess potential linkages between environmental and climatic variability. New macrofossil and pollen data at Lago della Costa unambiguously document the local persistence of boreal tree taxa such as Larix decidua and Betula tree species around the study site during the last Glacial. The regular occurrence of pollen of temperate trees in the organic lake sediments (fine-detritus calcareous gyttja) suggests that temperate taxa such as Corylus avellana, Quercus deciduous, Tilia, Ulmus, Fraxinus excelsior, Carpinus, Abies alba and Fagus sylvatica, most likely survived the Last Glacial Maximum (LGM) at favorable sites in the Euganean Hills. The percentage values of temperate trees are comparable with those from Southern Europe (e.g. Monticchio in Southern Italy). We conclude that the Euganean Hills were one of the northernmost refugial areas of temperate taxa in Europe. However, the relative and absolute abundances of pollen of temperate trees are highly variable. Pollen-inferred declines of temperate tree communities (e.g. Quercetum mixtum) and low ostracod-inferred water levels at Lago della Costa correspond to the cold Heinrich events H-2 (LGM; 23,000–19,000 cal. BP) and H-3 (around 28,000 cal. BP), as recorded in the marine sediments of the North Atlantic. Similar patterns of significant temperate tree population collapses during cold Heinrich events are recorded at southern Mediterranean sites (e.g. Monticchio and the Alboran Sea). These findings suggest close linkages between Northern Atlantic and South-Central European climates during the past Glacial.  相似文献   

8.
The glacial history of the Tagliamento morainic amphitheater (southeastern Alpine foreland, Italy) during the last glacial maximum (LGM) has been reconstructed by means of a geological survey and drillings, radiocarbon dating and pollen analysis in the amphitheater and in the sandur. Two phases of glacial culmination, separated by a distinct recession, are responsible for glacial landforms and related sediments in the outer part of the amphitheater. The age of the younger advance fits the chronology of the culmination of the last glaciation in the Alps, well established between 24 and 21 cal ka BP (20 to 17.5 14C ka BP), whereas the first pulse between 26.5 and 23 cal ka BP (22 to 21 14C ka BP), previously undated, was usually related to older (pre-LGM) glaciations by previous authors. Here, the first pulse is the most extensive LGM culmination, but is often buried by the subsequent pulse. The onset and final recession of the late Würm Alpine glaciation in the Tagliamento amphitheater are synchronous with the established global glacial maximum between 30 and 19 cal ka BP. The two-fold LGM glacial oscillation is interpreted as a millennial-scale modulation within the late Würm glaciation, caused by oscillations in inputs of southerly atmospheric airflows related to Dansgaard-Oeschger cycles. Phases of enhanced southerly circulation promoted increased rainfall and ice accumulation in the southern Alps.  相似文献   

9.
Marine Isotope Stage 11 (MIS 11) is considered one of the best analogues for the Holocene. In the UK the long lacustrine sequence at Marks Tey, Essex, spans the entirety of the Hoxnian interglacial, the British correlative of MIS 11c. We present multiproxy evidence from a new 18.5‐m core from this sequence. Lithostratigraphy, pollen stratigraphy and biomarker evidence indicate that these sediments span the pre‐, early and late temperate intervals of this interglacial as well as cold climate sediments that post‐date the Hoxnian. The δ18O signal of endogenic carbonate from this sequence produces several clear patterns that are interpreted as reflecting the climatic structure of the interglacial. As well as providing evidence for long‐term climate stability during the interglacial and a major post‐Hoxnian stadial/interstadial oscillation the δ18O signal provides strong evidence for abrupt cooling events during the interglacial itself. One of these isotopic events occurs in association with a short‐lived increase in non‐arboreal pollen (the NAP phase). The results presented here are discussed in the context of other MIS 11 records from Europe and the North Atlantic, particularly with respect to our understanding of the occurrence of abrupt climatic events in pre‐Holocene interglacials. Copyright © 2016 The Authors. Journal of Quaternary Science Published by John Wiley & Sons Ltd.  相似文献   

10.
Phytoliths extracted from loess resting conformably on lacustrine sediments in southeastern North Island, New Zealand, provide a nearly continuous vegetation–climate record spanning the time period from the last interglacial (Marine Oxygen Isotope Stage 5) to the present. Phytoliths reveal changes in vegetation patterns following changes in climate. Correlation between tree–shrub phytolith fluctuations and the SPECMAP oxygen isotope curve, between Marine Oxygen Isotope Stages 1 and 5, suggest that changes in the ratio of arboreal to non‐arboreal phytoliths directly result from changes in climate. These data generally support the existing pollen and diatom record. This study confirms the usefulness of phytolith fossils for providing environmental and climate information from the Quaternary sedimentary record, especially in cases where the deposits contain no fossil pollen or diatoms. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献   

11.
This paper presents a quantitative reconstruction of the European late Pleistocene paleoclimate based on 72 rodent assemblages of five sequences from France, Germany and Bulgaria, covering the last interglacial-glacial cycle. They show a pattern of severe changes in temperature, with reduced precipitation during the coldest periods. A tentative correlation between the isotopic and palynological records and the paleotemperature changes is shown. These changes are consistent with variations in atmospheric circulation patterns in response to an expanding-retracting Fennoscandian ice-sheet. They can be attributed to the enhancement-weakening of the Scandinavian-Polar anticyclone and its associated dry winds, the south-north shifting of the North Atlantic Polar Front, and the varying supply of moist air from the Atlantic. Qualitative paleoenvironmental analysis shows broadleaved-deciduous forests in France and Bulgaria during most of the studied period. Taiga and tundra appeared in eastern France during the lower Würm. The German sequence indicates the presence of coniferous forests. These results are broadly consistent with other paleobiological records (mammalian, avian and insect faunas, isotopic record in dental tissue, palynology). The main discrepancies with the paleoclimate inferred from the palynological record are found during the coldest periods and are probably due to the interaction between vegetation, climate, and atmospheric CO2 levels.  相似文献   

12.
This paper describes and discusses the palaeobotanical data obtained from organic levels of two exposed deposits on the Atlantic shore of the northwestern Iberian Peninsula. Radiocarbon dating assigns these levels to a period of marine regression at the end of MIS 3 and the beginning of the Last Glacial Maximum. The pollen record shows an initial predominance of tree taxa (mainly deciduous, including the presence of Fagus far from its current limit), followed by an episode of partial forest retraction related to the end of MIS 3 and the beginning of the Last Glacial Maximum. However, the presence of numerous tree taxa in the record, even during the cold intervals associated with Heinrich events, points to the existence of sheltered refugia for these species during this period, in keeping with the conclusions of recent reviews of the vegetation dynamics of this region for the Lateglacial and the Holocene.  相似文献   

13.
The pollen record at Area Longa is the westernmost sequence available for investigation of the last glaciation in continental Europe. It is located in a region, NW Iberia, for which data from times earlier than the late glacial period are scarce. It comprises a series of exposed limnetic levels that lie above an Eemian (Oxygen Isotope Stage [OIS] 5e) beach and are separated by inorganic layers. The oldest limnetic level (Level I), attributed to the early glacial period (OIS 5a to OIS 5d), shows a dominance of woodland with high proportions of Fagus pollen and is tentatively identified with St. Germain I. The lower pleniglacial (OIS 4) Level II records a stadial landscape of grassland and shrub. Level III, from the pleniglacial interstade (OIS 3), reflects a complex period in which three warmer woodland phases alternated with periods of more open vegetation. This cyclical behavior correlates with the ice core isotope record and with the general tendencies observed in other Würmian pollen records, but the composition of our pollen profiles differs from those observed in these other records. In NW Iberia, the dominant trees were deciduous taxa, not conifers. Of particular note is the presence of lowland Fagus woodlands during the pre-Würm, and the occurrence of Carpinus considerably farther west than the boundary of its current distribution in the Iberian Peninsula.  相似文献   

14.
At Airedale Reef, western North Island, New Zealand, a ca. 4 m thick volcanogenic debris avalanche deposit has facilitated the preservation of an enveloping sequence of peats with interbedded andesitic tephras spanning marine isotope (MIS) 5. The sequence closely overlies a wave‐cut terrace correlated to MIS 5e and, in turn, is overlain by andic beds with tephra interbeds including the Rotoehu and Kawakawa tephras deposited during early MIS 3 and mid‐MIS 2, respectively. Pollen analysis of the organic sequence shows a coherent pattern of fluctuating climate for the Last Interglacial–Last Glacial transition that corresponds with marine isotope stratigraphy and supports the contention that orbital variations were a primary factor in late Quaternary southern mid‐latitude climate change. A five‐stage subdivision of MIS 5 is clearly recognised, with marine isotope substage (MISS) 5b drier than MISS 5d, and the cooling transition from 5a to MIS 4 also may have been comparatively dry and characterised by natural fire, perhaps associated with volcanism. Several other examples of volcanic impact on vegetation and the landscape are evident. The Airedale Reef sequence exhibits strong similarities with fragmentary MIS 5 pollen records preserved elsewhere in New Zealand and enables the proxy record of southern mid‐latitude climatic variability during the Last Interglacial–Glacial cycle to be extended. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

15.
The pollen stratigraphy of Bucyrus Bog records the major shifts in the spruce ecotone of the mid-western North American late-glacial. The site has been studied three times: in 1930 by Paul Sears, in 1958 by Johannes Iversen, and in 1986–88 by my self. This paper examines these data sets from a historical perspective. The pollen record is basically consistent; all investigators interpret it to show the classic late-glacial warming plus a subsequent, more controversial climate reversal. Sears saw a progressive shift from cold/moist to warm/ dry climate, with a moisture reversal near the top of the record. Iversen and I both correlate the record with the European Late-Glacial climatic sequence, including an AUerød/Younger Dryas reversal. Iversen's interpretation depends on exclusion of thermophilous deciduous pollen taxa, placing the cold reversal during the spruce decline. I include the deciduous taxa, placing the cold reversal at the time of a spruce recurrence above the expansion of deciduous types. All interpretations are strongly influenced by current technology and prevailing thinking at the time of the investigation.  相似文献   

16.
Two radiocarbon-dated Lateglacial pollen diagrams from the Vale of Mowbray (northern Vale of York) are presented from sites in the lowlands between the washlands courses of the rivers Swale and Ure in North Yorkshire, an area with little previous palynological research despite its proximity to the Devensian glacial advance limits in eastern England. The profiles, from Snape Mires and Nosterfield, include the Loch Lomond Stadial (Younger Dryas) and the Holocene transition, while that from Snape Mires also includes the period from the early part of the Lateglacial Interstadial. This profile differs from most published Interstadial diagrams from the Yorkshire region in having a long-delayed expansion of tree and shrub taxa. Juniperus (juniper) remains important after vegetation development takes place and the pollen record includes evidence of two cold climate oscillations before the maximum development of Betula (birch) woodland near the end of the Lateglacial Interstadial. At both profiles Artemisia (mugwort) frequencies are lower during the Loch Lomond Stadial than at many regional sites, probably due to edaphic factors in these lowland locations. The two sites provide valuable environmental data that enable comparison between the more wooded Lateglacial vegetation to the south in the Vale of York and Humberside and the more open contemporaneous vegetation to the north in the Durham and Northumberland lowlands.  相似文献   

17.
The vegetation on the northeastern margin of the Tibetan Plateau is highly sensitive to climatic changes and thus represents a potentially interesting environmental archive. Pollen samples from the Fanjiaping Loess section in Lanzhou on the western Chinese Loess Plateau (CLP) were analyzed in conjunction with OSL dating. The results indicate that pollen zone B (60.6–46.0 ka, correlative to the early MIS 3) had the greatest abundances of Cupressaceae, Tsuga, Gramineae and Cyperaceae of the entire section, suggesting a warm phase during the last glacial period. These pollen taxa decreased significantly in abundance in the zones C (46.0–39.0 ka) and D (39.0–27.0 ka), reflecting a substantial climate cooling from the middle MIS 3 to MIS 2. These results correlate with climate records from the South China Sea, the CLP, Baikal Lake, North America, North Atlantic Ocean and other regions, and probably correspond with the decline of northern high-latitude insolation and the increase of global ice volume from 50 to 20 ka. In particular, arboreal pollen, fern spore and algae abundances declined sharply since ～40 ka, while shrub and herb pollen reached the highest abundances. Conifer pollen Picea and Abies abundance also rose markedly and increased up the section. This implies significant climate deterioration and likely corresponded with substantial growth of the polar ice sheets since ～40 ka. The decreasing temperature caused by an insolation decline during the last glacial period probably reinforced the cooling effect in a ‘snow/ice/albedo’ feedback, which would result in less climate sensitivity to radiative forcing. Meanwhile, vegetation decline in the Northern Hemisphere during the last glacial period and tundra development at high latitudes possibly caused additional cooling, enhancing the growth of polar ice sheets since 40 ka. The development of polar ice sheets increased the polar-to-equator temperature and pressure gradients, strengthening the westerlies and supplying plenty of moisture to Northwest China during 40–30 ka. Lake sediments developed widely on the Tibetan Plateau during 40–30 ka, probably related to an increase in the seasonality of middle-to-low latitude insolation which caused an enhancement of glacier melting on the Plateau.  相似文献   

18.
东亚地区MIS 5时期孢粉记录的植被与气候研究进展   总被引：1，自引：0，他引：1  
末次间冰期(深海氧同位素5阶段,MIS 5,71~128 ka BP)离现代间冰期最近,对其认识有助于预测未来环境,而化石孢粉是恢复古植被与古气候的重要指标。通过对选择出的东亚地区孢粉记录的具有年代数据和孢粉图谱的古植被和气候研究的综合分析,初步认为:①MIS 5的植被格局可与现代间冰期即全新世的植被格局对比。②各区孢粉记录了MIS 5气候波动,部分地区可划分出5a,5b,5c,5d和5e,存在轨道尺度变化,千年尺度事件较少发现。③东亚季风是影响现代东亚季风区环境的主要因素,但日本可能还受到西风环流和洋流的影响;西风、印度季风和地形是影响青藏高原环境的主要因素。④东亚地区,特别是干旱半干旱区,分辨率较高的孢粉记录的环境变化仍需更深入的研究。  相似文献   

19.
Pollen diagrams of 10 peat sections taken in sedge tundra span as much as 10.730 radiocarbon years and show a varied sequence of pollen assemblages dominated by herbs and shrubs. Taxa, for the most part. belong to the Gramineae. Cyperaceae. Salix, Abuts, Beiula and Empelrum. The assemblages indicate scral changes in the vegetation, resulting from interaction of climate and of successive ashfalls from regional volcanoes, and suggest a patchwork of late Quaternary plant communities. This record from southernmost Beringia enlarges upon previous pollen records from the Aleutian Islands and from the southern part of the Bering land bridge region in western Alaska.  相似文献   

20.
何耀堂 《福建地质》2011,30(3):224-232
福建泉州晚第四纪沉积物中孢粉,晚更新世以气候适应范围较宽的木本植物花粉占优势,适应温暖湿润气候的蕨类植物孢子较少;早全新世二者含量相当;中全新世蕨类植物孢子增多,木本植物花粉退居第二;晚全新世蕨类植物孢子占绝对优势,木本植物花粉相对减少。草本植物花粉浓度始终不高,但随着时代更新,种类增多。区内微体古生物在晚更新世和早全...  相似文献   

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