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1.
Detailed, chronologically tightly constrained, lake-sediment-based geochemical and pollen records have enabled local changes in soil erosion, woodland cover and composition, and prehistoric farming impact to be reconstructed in considerable detail. The profile opens shortly after 7800 BC when tall canopy trees were well-established and presumably in equilibrium with their environment. A distinct perturbation that involved an increase in pine and birch, a decrease in oak and a minor opening-up of the woodland is regarded as the local expression of the 8.2 ka climate anomaly. Lack of response in the geochemical erosional indicators is interpreted as evidence for drier conditions. A short-lived, over-compensation in climate recovery followed the 8.2 ka event. Neolithic farming impact is clearly expressed in both the pollen and geochemical data. Both datasets indicate that Neolithic impact was concentrated in the early Neolithic (3715–3440 BC). In the interval 3000–2700 BC there appears to have been a break in farming activity. The pollen data suggest substantially increased farming impact (both arable and pastoral) in the Bronze Age, with maximum farming and woodland clearances taking place in the late Bronze Age (1155–935 BC). These developments are poorly expressed in the geochemical record, possibly due to within-lake changes.  相似文献   

2.
High‐resolution pollen and geochemical analyses conducted on a sediment profile from a small lake in County Sligo, Ireland, revealed that human development during the Neolithic was influenced by pronounced climatic oscillations. The primeval woodland around the lake experienced a considerable transformation coinciding with the elm decline at 3810 BC. The subsequent increase in summer temperatures and decrease in precipitation favoured wheat cultivation in the lake's catchment area, which was practised for approximately 140 years. A shift towards pastoral farming took place with the establishment of exceptionally dry conditions between 3650 and 3560 BC, when lake level and influx of allochthonous material were notably low. The onset of cool and wet conditions at the transition from the Early to Middle Neolithic possibly caused the initial decline of human activity in the area. Periods of particularly high precipitation during the Middle and early Late Neolithic contributed to the abandonment of the area by the first farmers. Comparison of the proxy record from the study site with other palynological and archaeological records from Ireland suggests that climatic variability on the decadal to centennial scale represented a primary control on the nature and duration of farming practices during the Neolithic. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

3.
The Holocene sediment of Lago Piccolo di Avigliana (Piedmont, Italy, 356 m a.s.l.) was dated by 14C and analysed for pollen to reconstruct the vegetation history of the area. The early‐ and mid‐Holocene pollen record shows environmental responses to centennial‐scale climatic changes as evidenced by independent palaeoclimatic proxies. When human impact was low or negligible, continental mixed‐oak forests decreased at ca. 9300 BC in response to the early‐Holocene Preboreal climatic oscillation. Abies alba expanded in two phases, probably in response to higher moisture availability at ca. 6000 and ca. 4000 BC , while Fagus expanded later, possibly in response to a climatic change at 3300 BC . During and after the Bronze Age five distinct phases of intensified land use were detected. The near synchroneity with the land‐use phases detected in wetter regions in northern and southern Switzerland points to a common forcing factor in spite of cultural differences. Increasing minerogenic input to the lake since 1000 BC coincided with Late Bronze—Iron Age technical innovations and probably indicate soil erosion as a consequence of deforestation in the lake catchment. The highest values for cultural indicators occurred at 700–450 and at 300–50 BC , coinciding with periods of high solar activity (inferred from Δ14C). This suggests that Iron Age land use was enhanced by high solar activity, while re‐occupation of partly abandoned areas after crises in earlier periods match better with the GRIP stable isotope record. On the basis of our data and comparison with independent palaeoclimatic proxies we suggest that precipitation variation was much more important than temperature oscillations in driving vegetation and societal changes throughout the Holocene. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

4.
The adoption of cereal cultivation is a key benchmark in the transition from Mesolithic hunter–gatherer foraging to Neolithic farming economies, but the nature, timing and ecological–cultural context of the earliest cereal use in the British Isles and northwest Europe is still uncertain. We present AMS radiocarbon dating and fine‐resolution pollen evidence from the Isle of Man for cereal growing in the latter stages of a distinct episode of forest disturbance at almost 6000 yr BP (uncalibrated). The coherent ecological structure of this phase at the fine resolution level suggests that it records cereal cultivation well before the Ulmus decline, rather than wild grass pollen grains. This example is one of a cluster of early dates for cereal‐type pollen near the start of the sixth millenium BP, including several around the Irish Sea, which indicate that the introduction of cereal agriculture probably occurred as early in the central British Isles as in the northern European plain. This early cereal phase is followed later by a probable phase of pre‐Ulmus decline pastoral activity. We also report Mesolithic age woodland disturbance around 7000 yr BP (uncalibrated) and the first radiocarbon dates for mid‐Holocene forest history of the Isle of Man. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

5.
Results of palaeoecological studies involving pollen analytical, chemical and palaeomagnetic investigations on a 3 m core from Lough Doo, NE County Mayo, are presented. The record, which commences shortly after 7000 BP, shows a sharp Alnus expansion coinciding with a decline in Pius at 6400 BP, an elm decline taking place in the context of severe soil erosion and the final decline of Pinus occurring as the chemical record indicates onset of severe reducing conditions in the catchment. Pine becomes extinct at or shortly before 3200 BP in the context of increased farming activity and the expansion of blanket bog in the adjacent upland areas. A later feature (c. 1880 BP) is the expansion of Taxus to 7.1% of total pollen. On the basis of the palynological evidence, it is concluded that there were no major Neolithic Landnam phases, which contrasts sharply with the evidence for widespread woodland clearance and the laying out of extensive and regular field systems in the northern coastal part of County Mayo. In the upper part of the core a severe inversion of 14C dates is recorded. On the basis of the palaeomagnetic and pollen evidence this began at c. 1500 BP and is considered to have been initiated in the context of woodland clearance and a renewal in farming activity.  相似文献   

6.
The peatlands of northern Scotland (one of the largest and most intact areas of blanket bog in the world) contain a rare widespread horizon of subfossil pine in stratigraphic context. Eighteen bog pine from three new sites are incorporated into a mean Neolithic pine chronology now composed of subfossil pine from 12 sites, which is tree‐ring‐dated against Irish bog pine chronologies to span 3198–2757 BC. Germination and peaks of radial growth infer drier conditions between 3199 and 3130 BC. Dying‐off phases and depression of growth reflect a change to wetter conditions between 3023 and 3002 BC and a terminal decline of pine between 2809 and 2782 BC. The close synchronization of germination/die‐off phases and major ring‐width variations between sites across this region indicates that the environmental changes are probably triggered by climate change. Twenty‐four bog pine samples remain unmatched. Future multi‐discipline research into this important example of climatic change at the Neolithic/Bronze Age transition is recommended. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

7.
The alluvial deposits near Gibala-Tell Tweini provide a unique record of environmental history and food availability estimates covering the Late Bronze Age and the Early Iron Age. The refined pollen-derived climatic proxy suggests that drier climatic conditions occurred in the Mediterranean belt of Syria from the late 13th/early 12th centuries BC to the 9th century BC. This period corresponds with the time frame of the Late Bronze Age collapse and the subsequent Dark Age. The abrupt climate change at the end of the Late Bronze Age caused region-wide crop failures, leading towards socio-economic crises and unsustainability, forcing regional habitat-tracking. Archaeological data show that the first conflagration of Gibala occurred simultaneously with the destruction of the capital city Ugarit currently dated between 1194 and 1175 BC. Gibala redeveloped shortly after this destruction, with large-scale urbanization visible in two main architectural phases during the Early Iron Age I. The later Iron Age I city was destroyed during a second conflagration, which is radiocarbon-dated at circa 2950 cal yr BP. The data from Gibala-Tell Tweini provide evidence in support of the drought hypothesis as a triggering factor behind the Late Bronze Age collapse in the Eastern Mediterranean.  相似文献   

8.
The Late Paleolithic sites existed in cold and dry climat (Ustinovka I, 10–25 ky ago; Ust-Ulma, 19, 360 ± 65 BP) with warmer stages (Suvorovo IV, 15,300 ± 140 BP) and on the Pleistocene/Holocene transition, near 10,000 BP (Suvorovo III). The Final Paleolithic sites existed in Late Glacial time, 10,000–12,000 BP (Gorbatka III, lower level) and in Boreal period, 8,000–9,000 BP (Ilistaya I, 7, 840 ± 60 BP; Timofeevka I). The Developed Neolithic sites existed during the warm and humid Middle-Late Atlantic period, 6,000–8,000 BP; the Late Neolithic sites — 3,000–5,000 BP. The human impact in the Paleolithic-Neolithic was restricted to burning and trampling the vegetation near the sites; the bases of paleoeconomy were hunting, fishing, gathering. The presence of pastoral anthropogenic indicators in pollen spectra of the Neolithic sites may reflect the beginning of cattle breeding.The Bronze Age (end of the 4th-2nd millenia BC) provides the first reliable evidence of cultivated plants (foxtail and Japanese millet) and domestic animals (pig, dog). In the paleoeconomy agriculture and cattle breeding appeared; the first stage of human impact increased (4,000–4,500 BP, ie 2550–3230 cal. BC) is reflected in pollen spectra from cultural layers. From the Early Iron Age to the Middle Ages (end of 2nd millenium BC-13th century AD) agriculture and cattle breeding were the base of paleoeconomy. From the 8th to the 10th centures AD, due to the development of ploughing (arable), the human impact intensified.Paper was presented on the 27th International Geographical Congress, Washington, DC, USA, August 9–14, 1992 (section Human Induced Environmental Change, the Ancient Past)  相似文献   

9.
New and existing pollen data from Wales, UK, are used to assess the level of landscape openness at the regional and local scale. At the regional scale, the existing pollen data support the high‐forest model of vegetation structure by 6000 cal. yr. BC prior to any palynological signal for anthropogenic impact in the region. New data from two sites in southwest Wales follow the general regional pattern of early to middle Holocene vegetation succession, but are striking owing to maintenance of high non‐arboreal pollen percentages (NAPs) throughout the mid‐Holocene. It is argued that these NAPs indicate that a significant degree of openness can be found at the local level (and beyond the confines of the peat‐forming site) within regions characterised by closed woodland. It is possible that woodland development in these areas may have been suppressed by reduced drainage, although the role of grazing animals in maintenance of clearings cannot be assessed. Implications for this local degree of openness are discussed, in particular the significance of vegetation heterogeneity at the local scale for the construction of place or locale for prehistoric communities. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

10.
This paper presents the first systematic study of the vegetation history of a range of low hills in SW England, UK, lying between more researched fenlands and uplands. After the palaeoecological sites were located bespoke archaeological, historical and documentary studies of the surrounding landscape were undertaken specifically to inform palynological interpretation at each site. The region has a distinctive archaeology with late Mesolithic tool scatters, some evidence of early Neolithic agriculture, many Bronze Age funerary monuments and Romano‐British iron‐working. Historical studies have suggested that the present landscape pattern is largely early Medieval. However, the pollen evidence suggests a significantly different Holocene vegetation history in comparison with other areas in lowland England, with evidence of incomplete forest clearance in later‐Prehistory (Bronze?Iron Age). Woodland persistence on steep, but poorly drained, slopes, was probably due to the unsuitability of these areas for mixed farming. Instead they may have been under woodland management (e.g. coppicing) associated with the iron‐working industry. Data from two of the sites also suggest that later Iron Age and Romano‐British impact may have been geographically restricted. The documented Medieval land management that maintained the patchwork of small fields, woods and heathlands had its origins in later Prehistory, but there is also evidence of landscape change in the 6th–9th centuries AD. We conclude that the Blackdown Hills area was one of many ‘distinctive subregions’, which due to a combination of edaphic, topographic and cultural factors could qualify as an eco‐cultural region or ‘pays’. It is argued that the use of such eco‐culturally distinctive regions or pays can provide a spatial and archaeological framework for palaeoecology, which has implications for landscape research, designation and heritage management.  相似文献   

11.
The soils surrounding three Iron Age settlements on South Mainland, Shetland, were sampled and compared for indicators of soil amendment. Two of the sites (Old Scatness and Jarlshof) were on lower‐lying, better‐drained, sheltered land; the third (Clevigarth) was in an acid, exposed environment at a higher elevation. The hypothesis, based on previous regional assessments, soil thicknesses, and excavations at Old Scatness, was that the lowland sites would have heavily fertilized soils and that the thin upland soil would show little if any amendment. Our findings indicate that the Middle Iron Age soils at Old Scatness had extremely high phosphorus levels, while the soil at Jarlshof had lower levels of enhancement. At Clevigarth, where charcoal from the buried soil was 14C dated to the Neolithic and Bronze Age, there was no evidence of arable activity or soil amendment associated with the Iron Age phases of settlement. These observations indicate that not all sites put the same amount of effort into creating rich arable soils. The three sites had very different agricultural capacities, which suggests the emergence of local trade in agricultural commodities in Iron Age Shetland. © 2008 Wiley Periodicals, Inc.  相似文献   

12.
Despite the high potential of pollen records for climate reconstruction, pollen–climate relationships may be biased due to past and present human activities on the landscape. We use (i) transfer functions based on modern pollen–climate relationships to infer seasonal temperature and summer precipitation for the period 11 500–4500 cal. a BP and (ii) lake‐level change records based on different sedimentary proxies in multiple cores that are mainly indicative for summer hydrology at Lago dell'Accesa (central Italy). Quantitative reconstructions indicate lowest summer precipitation during two phases (8500–7700 cal. a BP and after 6000 cal. a BP) and a gradual winter temperature increase from 11 500 to ca. 8000 cal. a BP. Lowest summer precipitation was reconstructed during these phases characterised by vegetation shifts from open forests dominated by summergreen oaks (Quercus) to forests dominated by evergreen oaks (Quercus ilex), which are at present most abundant where summer drought is stronger. Similarly, the lake‐level record indicates two long‐lasting low summer precipitation phases (8800–7700 and 6400–4400 cal. a BP) that were interrupted by short‐term high summer precipitation events. Based on the broad agreement between the pollen‐inferred summer precipitation and the low‐frequency lake‐level changes, we suggest that the duration of the high summer precipitation events may have been too short to maintain drought‐sensitive trees, which may have been affected by high mortality rates when summer dry conditions returned. Although past and modern pollen–climate relationships may very likely have been affected by human activities since the Neolithic (i.e. when exploitation of the landscape started), we reject the hypothesis of a significant anthropogenic bias in the pollen‐based climate reconstruction. In addition, we suggest that pollen‐based and lake‐level reconstructions may have different inherent abilities of capturing high‐ and low‐frequency precipitation signals. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

13.
Palaeolimnological reconstruction of the aquatic environment in Lake Komo?any, based on sedimentology, geochemistry, and diatom and macrofossil analyses in the littoral part of the basin, reflects the mid‐Holocene history of the profile from its origin c. 9100 cal. a BP to its final transformation into an alder carr c. 4100 cal. a BP. The existence of the littoral zone can be best explained by increased precipitation during the studied interval. A stable diatom community, diatom‐inferred total phosphorus (50–80 μg L?1) and pH (~7.6), along with stable concentrations of elements associated with changes in its watershed indicate a long‐lasting, balanced aquatic environment with no major shifts attributable to external factors, including climate change. From c. 4700 cal. BP, there started a transition to terrestrial conditions, caused by either natural infilling processes or decreased precipitation. Alternation of remarkable dry/wet phases was not detected, in contrast to numerous analogous central European and supraregional records. Potential human impact was revealed through increases of Corylus and Populus pollen in the Neolithic. These anthropogenic changes in the lake surroundings had no detectable influence on the lacustrine environment. The gathered data suggest undramatic, balanced mid‐Holocene environmental and climatic settings for this central European locality, in direct contrast to numerous analogous studies from the region emphasizing fluctuations and shifts found in the sediment record.  相似文献   

14.
The arable soils from two multiperiod settlements were analyzed to identify changes in agricultural methods over time. The settlement middens were also analyzed to determine whether potential fertilizers were discarded unused. Results suggest that in the Neolithic period (˜4000–2000 B.C. in the UK) the arable soils at Tofts Ness, Orkney, and Old Scatness, Shetland, were created by flattening and cultivating the settlements' midden heaps in situ. The arable area at Tofts Ness was expanded in the Bronze Age (˜2000–700 B.C. in the UK), and the new land was improved by the addition of ash, nightsoil, and domestic waste. Cultivation continued briefly after the fields were buried in windblown sand in the Late Bronze Age or Early Iron Age, but by the Early Iron Age cultivation ceased and organic‐rich material was allowed to accumulate within the settlement. By contrast, at Old Scatness, arable production was increased in the Iron Age (˜700 B.C.–A.D. 550 in Scotland) by the intensive use of animal manures. The results indicate that during the lifespan of the two settlements the arable soils were fertilized to increase production, which was intensified over time. © 2006 Wiley Periodicals, Inc.  相似文献   

15.
This paper describes a multi‐proxy palaeoecological investigation undertaken in conjunction with an archaeological survey of the Upper Sangro Valley in the Abruzzo National Park, Central Italy. Despite being a biodiversity hotspot and regarded as a near‐pristine area, the pollen, spore and diatom data all show major changes in the vegetation extending to over 2000 m a.s.l. during the mid to late Holocene. Although there are changes in ecological composition earlier in the Holocene they are different in type and magnitude from the changes which began about 800 cal a BC. The pollen and diatom evidence do not correlate well with regional palaeoclimate data, or on‐site isotopic evidence, but do appear to be related to Samnite (later Iron Age) clearance and upland grazing associated with transhumance and later annexation (and centuriation) of the lower slopes by Roman surveyors. The greatest change in vegetation was during the period c. AD 500–600 and corresponds with the Byzantine–Gothic Wars, and Lombard–Carolingian settlement reorganization into nucleated hilltop settlements which managed upland grazing. This pattern of intensive land use at all altitudes persisted until the early 20th century and only changed following rural depopulation after World War II. These data illustrate how cultural factors had a profound effect on this mountainous region which, in this case, far outweighed the effects of climatic fluctuations which are known to have occurred from both this study area and the region. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

16.
Annually resolved June–July–August (JJA) temperatures from ca. 570 BC to AD 120 (±100 a; approximately 690 varve years) were quantified from biogenic silica and chironomids (Type II regression; Standard Major Axis calibration‐in‐time) preserved in the varved sediments of Lake Silvaplana, Switzerland. Using 30 a (climatology) moving averages and detrended standard deviations (mean–variability change, MVC), moving linear trends, change points and wavelets, reconstructed temperatures were partitioned into a warmer (+0.3°C; ca. 570–351 BC), cooler (?0.2°C; ca. 350–16 BC) and moderate period (+0.1°C; ca. 15 BC to AD 120) relative to the reconstruction average (10.9°C; reference AD 1950–2000 = 9.8°C). Warm and variable JJA temperatures at the Late Iron Age–Roman Period transition (approximately 50 BC to AD 100 in this region) and a cold anomaly around 470 BC (Early–Late Iron Age) were inferred. Inter‐annual and decadal temperature variability was greater from ca. 570 BC to AD 120 than the last millennium, whereas multi‐decadal and lower‐frequency temperature variability were comparable, as evident in wavelet plots. Using MVC plots of reconstructed JJA temperatures from ca. 570 BC to AD 120, we verified current trends and European climate model outputs for the 21st century, which suggest increased inter‐annual summer temperature variability and extremes in a generally warmer climate (heteroscedasticity; hotspot of variability). We compared these results to MVC plots of instrumental and reconstructed temperatures (from the same sediment core and proxies but a different study) from AD 1177 to AD 2000. Our reconstructed JJA temperatures from ca. 570 BC to AD 120 showed that inter‐annual JJA temperature variability increased rapidly above a threshold of ~10°C mean JJA temperature. This increase accelerated with continued warming up to >11.5°C. We suggest that the Roman Period serves with respect to inter‐annual variability as an analogue for warmer 21st‐century JJA temperatures in the Alps. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

17.
In the area of archaeological excavations that were performed prior to the construction of Main Road No. 86 in Vas County (West Hungary) in the Alpine foreland new geoarchaeological analyses have been conducted. We used anthracology and pollen analyses to reconstruct the former vegetation cover at the study site. Charcoal data provide site-related information about the local woodland composition, management and human impact, while pollen data provide information on the arboreal and non-arboreal vegetation on a regional or local scale. Adequate samples for anthracological analyses derive from the Bronze Age, Iron Age, Imperial and Migration Periods and Middle-Ages archaeological objects. The core for pollen analyses originates from alluvial sediments of the Borzó Creek and covers the late Pleistocene and the Holocene until the Medieval Period. Charcoal analyses show the dominance of Quercus trees in the vicinity of the human settlements that might indicate a strong human selection, or the fragmentation of samples. Pollen analyses indicate thermophilous vegetation from the beginning of the Holocene, with increasing values of Fagus and Carpinus. Pollens of cereals indicate human activity, which is also demonstrated by the presence of pollen from Juglans and Vitis in the Iron Age sequence. Extensive forest clearance occurred in the Late Iron Age and the Imperial Period.  相似文献   

18.
《Quaternary Science Reviews》2007,26(11-12):1476-1498
Palynological and sedimentological studies were performed at two Holocene profiles in erosion gullies (Ze’elim and Ein Feshkha) which dissect the retreating western shore of the Dead Sea. The aim of the project was to analyse possible links between climate, lithology, and vegetation development. The section in Ze’elim shows both lacustrine and fluvial sediments, whereas sedimentation at Ein Feshkha is predominantly lacustrine. The Ze’elim profile, previously used for paleo-lake reconstruction provides an opportunity to compare climate triggered lake levels as paleo-hydrological indicators and vegetation history by use of palynology. The vegetation development in Ze’elim and Ein Feshkha is influenced by both climate and human impact. The pollen record of Ze’elim begins in the Pottery Neolithic, the section of Ein Feshkha in the Late Bronze Age, both records end in the Middle Ages. The Ze’elim section is characterized by sedimentary hiati between the beginning of the Chalcolithic Period until the Middle Bronze Age and within the Late Bronze Age. Settlement periods during the Middle Bronze Age, Iron Age and Hellenistic–Roman–Byzantine Period are indicated by high values of anthropogenic indicators and/or Mediterranean trees. Collapses of agriculture, which can be related to climate effects, are evident during the Late Bronze Age, during the Iron Age and at the end of the Byzantine Period when the lake level curve indicates arid conditions. A comparison of the two pollen records, from different environments, illustrates a more prominent influence of Mediterranean vegetation and cultivated plants in the pollen diagram of Ein Feshkha. The southern Dead Sea region (at the desert fringe) is more vulnerable to regional climate change.  相似文献   

19.
This paper provides a summary of the palaeoenvironmental evidence from a spread of late Mesolithic burnt material and two late Neolithic to early Bronze Age burnt mounds. The burnt mounds were up to 10 m diameter, had an amorphous shape, and were consistently less than 0.8 m thick. Monoliths were collected from two sites, Ballygawley and Roughan, in Co. Tyrone, Northern Ireland. This provided an opportunity to use a detailed palaeoecological approach for the first time to investigate the use and function of burnt mounds. Pollen, non‐pollen palynomorphs, micro‐ and macroscopic charcoal were used to place these features within their environmental context, and to establish if such an approach could provide further insights into their function. The palynological results shared similar characteristics: high microscopic charcoal values, repetitive fluctuations in tree and shrub taxa, increased Sphagnum, and the presence of non‐pollen palynomorphs (NPPs) HdV‐114 and HdV‐146, all of which could be diagnostic indicators of burnt mounds in palynological records. While the data do not allow us to ascribe a specific function for the burnt mounds, their environmental setting is discussed. A “see‐saw” pattern of arboreal pollen, combined with the macroscopic charcoal data, indicate possible species selection and management of local woodland for fuelwood.  相似文献   

20.
Heikkilä, M. & Seppä, H. 2010: Holocene climate dynamics in Latvia, eastern Baltic region: a pollen‐based summer temperature reconstruction and regional comparison. Boreas, Vol. 39, pp. 705–719. 10.1111/j.1502‐3885.2010.00164.x. ISSN 0300‐9483. A pollen‐based summer temperature (Tsummer) reconstruction reveals the Holocene climate history in southeastern Latvia and contributes to the limited understanding of past climate behaviour in the eastern sector of northern Europe. Notably, steady climate warming of the early Holocene was interrupted c. 8350–8150 cal. yr BP by the well‐known 8.2 ka cold event, recorded as a decrease of 0.9 to 1.8 °C in Tsummer. During the Holocene Thermal Maximum, c. 8000–4000 cal. yr BP, the reconstructed summer temperature was ~2.5–3.5 °C higher than the modern reconstructed value, and subsequently declined towards present‐day values. Comparison of the current reconstruction with other pollen‐based reconstructions in northern Europe shows that the 8.2 ka event is particularly clearly reflected in the Baltic region, possibly as a result of distinct climatic and ecological gradients and the sensitivity of the vegetation growth pattern to seasonal temperature change. The new reconstruction also reveals that the Holocene Thermal Maximum was warmer in Latvia than in central Europe and Fennoscandia. In fact, a gradient of increasing positive temperature anomalies is detected from northernmost Fennoscandia towards the south and from the Atlantic coast in Norway towards the continental East European Plain. The dynamics of the temperate broadleaved tree species Tilia and Quercus in Latvia and adjacent northern Europe during the mid‐Holocene give complementary information on the multifaceted climatic and environmental changes in the region.  相似文献   

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