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1.
Detailed botanical (microfossil and macroremain), zoological and geochemical analyses (major and trace elements including C, Al, S, Ca, Fe, P, As, Zn, U, Ba and Rare Earth Elements) of organic deposits provide new insights into Early Holocene environmental change in the Kreekrak area (southwestern Netherlands). The age assessment of the record is based on high resolution AMS 14C wiggle-match dating (WMD). For the first time an AMS 14C WMD based chronology covering the Late Glacial/Holocene transition and early Preboreal is introduced for a site in The Netherlands.The Kreekrak botanical record reflects the end of the Younger Dryas to early Boreal and can be well correlated with pollen records from other sites in The Netherlands and Belgium. The palaeo-topography showed that the Kreekrak deposits formed in an abandoned channel of the River Schelde. Around ca. 11,490 cal BP, at the end of the Late Glacial/Holocene transition, infilling of the lake started with predominantly organic deposits in slowly running water. As a result of the warmer climate the area became forested with birch and poplar during the Friesland Phase (ca. 11,490-11,365 cal BP). Biological productivity of the lake and its surroundings increased. Aquatic vegetation developed in the lake, while shrubs of willow, reed swamps and grasslands fringed the shores. Precipitation increased, which caused a rise in the lake water table and an increase in the supply of oxic surface (= river) water into the Kreekrak lake. During this period, the Kreekrak lake was fed by inflowing river water, run-off, precipitation and seepage of Fe-rich groundwater. Around ca. 11,435 cal BP the water became stagnant probably as result of a total cut-off of the river channel. Inflow of river water ceased, while the supply of reduced Fe-rich groundwater became dominant. During the Rammelbeek Phase (ca. 11,365-11,250 cal BP), the climate was more continental and the abundance of grasslands and open herbaceous vegetation increased. Biological productivity remained high. In the lake, the supply of Fe-rich groundwater continued, the water level slightly decreased but aquatic vegetation remained present. At the end of the Rammelbeek Phase a sudden reduction in the supply of Fe-rich reduced groundwater caused a lowering of the groundwater level in the area, resulting in the development of a hiatus. Due to this hiatus, the Late Preboreal (11,250-10,710 cal BP) is absent from the record. During the early Boreal (10,710-10,000 cal BP) the landscape became densely forested and accumulation of peat in the former lake resumed due to a slowly rising groundwater level. The Boreal was a relatively stable period with low sedimentation rates.The combination of palaeobotanical and geochemical analyses in the Kreekrak record shows a close interrelation between landscape development and geochemistry. It appears that the environmental development of this area during the Late Glacial/Holocene transition and Early Holocene was largely influenced (directly or indirectly) by major climatic changes that occurred during this period, which determined local phenomena such as the composition and density of the vegetation, occurrence of seepage and river activity. Further research of this type has the potential to develop the application of major- and trace element geochemistry in palaeoenvironmental reconstructions.  相似文献   

2.
An archaeological excavation in the Tungelroyse Beek valley revealed the remains of two red deer specimens (Cervus elaphus) of Early Mesolithic age that possibly were the victims of hunter-gatherers. The find of animal remains of this age is unique in the Netherlands. In this respect, a sediment core taken close to the remains was investigated, i.e. to reconstruct the vegetation and landscape development of the site and to find more evidence for human activity at this site during the Early Mesolithic. The sediment core shows a typical Early Holocene palynological sequence from the Younger Dryas into the Middle Atlantic, which is supported by AMS dating. The microscopic charcoal record shows peaks in fire activity during the Younger Dryas and Friesland phase, probably wildfire related. Records of spores of coprophilous fungi indicate that the Tungeroyse Beek valley was a favourable place for large herbivores (game) to visit during the investigated period. However, around the age of the oldest red deer remains, no significant peak in fire activity or spores of coprophilous fungi is visible in the investigated record. The pollen diagram does not show disturbed or open vegetation around this age either. This study therefore suggests the impact of Early Mesolithic people on their environment was very low.  相似文献   

3.
In the geological research of the Holocene coastal deposits of The Netherlands, diatoms are used to reconstruct the sedimentary facies, palaeo-tide levels and salinity gradients during the deposition of the sediments. In this paper, the results of diatom research from 4 borings, taken from the early and middle Holocene deposits of central North Holland are presented. The oldest marine influenced sediments in the area are the deposits of the ‘Velsen layer’, a clay layer rich in organic matter and deposited about 8000–700014C years before present (BP) at a depth of 20–12 m below present mean sea-level. This clay layer was formed in a shallow, permanently submerged environment with a limited tidal influence (lagoonal or pond-like conditions). The salinity changed from brackish/freshwater to marine/brackish. The younger sandy and clayey sediments, formed about 7000–4500 BP at a depth of 16–3 m below present mean sea-level, are classified as ‘tidal channel’ and ‘interchannel’ deposits. It is argued, on the base of both diatom and non-diatom criteria, that the lower and middle parts of the interchannel deposits in the central area of the palaeo-tidal basin of North Holland were formed in a subtidal environment. The upper part of the interchannel deposits and the deposits at the fringe of the North Holland tidal basin were formed in the intertidal zone or, at the fringe of the basin, even in the supratidal zone. The salinity in the North Holland tidal basin during the sedimentation of the tidal channel and interchannel deposits was marine/brackish to marine. This study indicates that diatoms, besides their palaeoecological applications, have chronostratigraphical significance (on a regional scale). The diatomsCymatosira belgica andActinoptychus splendens appear to be a useful (eco)stratigraphical marker in the Holocene coastal deposits of The Netherlands and Belgium.  相似文献   

4.
The Weichselian Late-glacial marks the transition from the Weichselian Late Pleniglacial to the warmer Holocene. During this period climate changed rapidly, as did vegetation and the abiotic landscape. For analysis of the relationship between these changes, accurate chronologies are essential. In the Netherlands, a compilation has been made of over 250 palynologically investigated sites relating to this period. A regional zonation has been constructed based on common trends in vegetation development. On palynological grounds, not only the classical Late-glacial sub-division but also minor changes can be recognized within the Allerod, Late Dryas and Early Preboreal. After a critical evaluation of the available radiocarbon dates this zonation has been attached to the14C timescale. Palynological changes which can be attributed to episodes of climatic cooling are recorded at 12 100, 11 500, 10 950 and 9950 B.P. The chronological framework made it possible to compare vegetation development with other proxy records. Climatic events recorded in oxygen-isotope records from Swiss lake sediments and the Greenland ice cores are also reflected in the regional vegetation development in the Netherlands. The regional trends in vegetation development expressed by the pollen zones are considered to be related to changes in climate, while anomalies reflect other, local environmental changes.  相似文献   

5.
Successive generations of hunter–gatherers of the Late Glacial and Early Holocene in Iberia had to contend with rapidly changing environments and climatic conditions. This constrained their economic resources and capacity for demographic growth. The Atlantic façade of Iberia was occupied throughout these times and witnessed very significant environmental transformations. Archaeology offers a perspective on how past human population ecologies changed in response to this scenario. Archaeological radiocarbon data are used here to reconstruct demographics of the region over the long term. We introduce various quantitative methods that allow us to develop palaeodemographic and spatio-temporal models of population growth and density, and compare our results to independent records of palaeoenvironmental and palaeodietary change, and growth rates derived from skeletal data. Our results demonstrate that late glacial population growth was stifled by the Younger Dryas stadial, but populations grew in size and density during the Early to Middle Holocene transition. This growth was fuelled in part by an increased dependence on marine and estuarine food sources, demonstrating how the environment was linked to demographic change via the resource base, and ultimately the carrying capacity of the environment.This article is part of the theme issue ‘Cross-disciplinary approaches to prehistoric demography’.  相似文献   

6.
Nine sites along the downstream and middle section of the Loire river at Cordemais (Loire Atlantique, France) situated in the estuary to Saint-Nicolas-de-Bourgueil (Indre et Loire, France) were investigated. Interdisciplinary studies combined palynology, geography, archaeology, sedimentology and history, thus enabling us to reconstruct the evolution and the long-term response of the Loire valley ecosystem to natural variations and anthropogenic pressure from the Preboreal to the present in an integrated manner. The Atlantic marine transgression (between 7000 and 5000 B.P.) caused the level of brackish water to increase at Oudon between 6740+205/–200 and 5010+115/–100 B.P. This phenomenon, which was the first of its kind to be detected near the central Loire region (approximately 80 km from the current mouth of the Loire river), was accompanied by the development of subhalophile vegetation (Chenopodiaceae) and the appearance of dinoflagellate cysts. A regressive phase occurred during the Subboreal, about 4500 B.P., and led to the erosion of most of the estuarian sediments and to the disappearance of plant species linked to salinity at Oudon: peat deposits built up at most other sites. Human activities had an early effect; moderate deforestation took place at Champtocé about 6600 B.P. as farming was already orientated towards rearing animals. However, possibly cultivated plants were present towards the middle and the end of the Neolithic period (wheat, rye, buckwheat, flax) at about 5600 B.P. and chestnut and walnut were probably exploited in the Loire valley region at about 4600 B.P. The Bronze Age seemed to mark a phase when societies settled down (planting of vineyards) and deforestation peaked from the Gallo-Roman period onwards. The textile industry (flax, hemp), in the context of crop rotation set up during the Iron Age, developed rapidly during the Middle Ages, whereas nowadays the rearing of animals is the dominant activity in the Loire Valley, following the introduction of maize into the region in 1950.  相似文献   

7.
《Palaeoworld》2019,28(3):346-360
The palynological and macrofloral assemblages from the Lower Member of the Ukurey Formation have been studied based on the materials from a section exposed along the Kulinda Ravine (Olov Depression, Transbaikalia). This section is of special interest due to the occurrence of ornithischian dinosaurs. Based on palynological and palaeobotanical data, the studied deposits are dated as Middle Jurassic (Bathonian). Specific features of the palynological assemblages allow the correlation of the studied interval with Western Siberian palynozones calibrated by ammonite and foraminiferal successions. The resulting biostratigraphy suggests that the lower extent of the Ukurev Formation is not restricted to the Upper Jurassic as previously assumed. Lacustrine origin of the Lower Member of the Ukurev Formation is confirmed based on palaeoenvironmental analysis, showing changes of the terrestrial vegetation, associated with climatic conditions and fluctuations of the lake-level. Palaeobotanical and palynological data suggest that Middle Jurassic floras of eastern regions of Central Asia, southern regions of Siberia and Far East, as well as northern regions of China exhibit similar features.  相似文献   

8.
Changes are reported of Crataegus-Betula dune woodlands between 1950–1980 from Meijendel, a calcareous coastal dune system near the city of The Hague, The Netherlands, which is used as a water catchment area. It concerns both woodlands in degradation stage and, more common, woodlands on the increase. Changes were recorded with help of successive vegetation maps, air photos and permanent plot observations. Woodland increase usually occurs on places with groundwater at or near the surface, either because of natural circumstances or as a result of artificial groundwater recharge through infiltration as part of the water catchment activities. The management of both types of woodland is discussed.Nomenclature follows Heukels-van der Meijden (1983), Flora van Nederland, 20th ed. Wolters-Noordhoff, Groningen. Nomenclature of mosses follows Margadant & During (1982), Beknopte Flora van Nederlandse Blad- en Levermossen, Thieme, Zutphen.The authors have pleasure in thanking their colleagues from the Dune Water Works who supplied data on hydrology.  相似文献   

9.
Tybrind Vig is a late Mesolithic (Ertebølle) coastal settlement, dated to the period 5600–4000 BC. The site has yielded some very important finds associated with fishing activity, probably the best preserved example from the Mesolithic in Europe. Recently analysed botanical samples from submerged cultural deposits have provided evidence for the contribution of plants to the subsistence diet of the inhabitants of Tybrind Vig. The food plant remains are represented by the charred fragments of parenchymatous tissue from roots ofBeta vulgaris ssp.maritima (sea beet), fragments ofQuercus sp. parenchyma (acorn), and shell fragments ofCorylus avellana (hazelnut). The possibility that the grains ofGlyceria fluitans (floating sweet grass) and stems ofPhragmites australis (reed) were collected for food should not be excluded. In addition to the species identified in the charred remains, an abundance of edible plant seeds and fruits were represented in the waterlogged remains, suggesting that a much broader range of food plants was available in the area. These additional foods could have included a large variety of wild berries and other fruits, such asRubus idaeus, R. caesius, Fragaria vesca, Malus sylvestris, Cornus sanguinea, Crataegus monogyna/laevigata, Sorbus aucuparia, Viburnum opulus andRosa spp. Several other plants could have been gathered as green vegetables (Rumex crispus, Urtica dioica andCakile maritima), or could have been utilized for both their greens and seeds (Chenopodium album, Atriplex andScirpus maritimus).  相似文献   

10.
Despite being rich in later prehistoric and historic archaeology that includes megalithic monuments, Bronze age copper mines and medieval castles, the Mizen Peninsula, south-west Ireland, has revealed little about its stone age past. Evidence for a Mesolithic presence in SW Ireland is rare and, to date, all archaeological finds of this age in Co. Cork are further north and east of the Mizen Peninsula. However a recent palaeoecological study of pollen, non-pollen palynomorph, plant macrofossil and microscopic charcoal data from a peat bog located near Mount Gabriel has provided evidence for disturbances, characterised by fire disturbance of woodland and exploitation of wetlands, since ca. 8400 years b.p. Two working hypotheses are considered to explain these disturbances: human activity or natural agencies. If the human activity hypothesis is accepted, they represent the first possible evidence of a Mesolithic presence on the Mizen Peninsula.  相似文献   

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14.
This paper reports laboratory experiments on dinitrogen fixation and denitrification for two small quaking fens (discharge fen and recharge fen) using the acetylene reduction assay and the acetylene inhibition technique, respectively.Nitrogenase activity was detected in peat muck and associated with Alnus glutinosa saplings throughout the study period (May–October 1987), whereas no activity was observed with Sphagnum species. The annual amount of dinitrogen fixed was estimated at 2.1 and 12.7 kg N/ha/y for the recharge fen and the discharge fen, respectively.Denitrification at ambient nitrate levels (0.1 ppm NO3) was absent in the discharge fen and very low in the recharge fen (0.1 g N/g/d, or 0.3 kg N/ha/y). In nitrate-amended soil samples denitrification rates were 2 to 3 orders of magnitude higher. It is argued that in situ denitrification rates in the fens studied will depend almost entirely on the nitrate supply by precipitation. Denitrification rates associated with precipitation are estimated at 1.1 kg N/ha/y for both fens.  相似文献   

15.
A palynostratigraphic and palynofacies study of a geological section at Cuojiangding in Zhongba County has provided a basis for discussing the palaeoenvironmental evolution of the southern continental margin of Laurasia in Xizang (Tibet) towards the end of the Cretaceous Period and during the Paleogene. It is the only record of fossil spores and pollen grains from collision- and convergence-related sediments close to the major Yarlung Zangbo Suture. Deposits of the Padana Formation at the base of the section through the Qubeiya, Quxia, and Jialazi formations to the Rujiao Zangbo Conglomerate at the top are considered to range in age from Santonian to Eocene or possibly Oligocene. During this period the India plate collided with, and continued to push against, Laurasia plate. Two spore and pollen zones and three palynofacies types are recognized. These are correlated with two transgressive–regressive cycles associated with the collision, periods of geologically rapid uplift being reflected by the molasse-like sediments of the upper Quxia Formation and the Rujiao Zangbo Conglomerate, which accumulated during the Late Paleocene and Eocene–Oligocene respectively. The first regression led to intermittent subaerial exposure and erosion of the Cuojiangding area. The second ended the marine history of the area and led first to the development of swamps in a subtropical climate, now preserved in the coal-bearing Qiuwu Formation, and later to the development of mountainous terrain, with a cooler climate at higher elevations.  相似文献   

16.
Ferrissia wautieri, a freshwater limpet, is a widely distributed species in The Netherlands. In a pond near Nijmegen samples were taken twice a month over the year to study the population size and structure of this species in relation to the water temperature. Only ancyloids were found. Production of juveniles is temperature-dependent; peak numbers occurred in July and August. Just-hatched juveniles (shell length 0.6–1.0 mm) occurred over a lengthy period in the year, but were absent in March and April. During these months the collected numbers of specimens were very low. The largest specimens were collected during March, April and May.  相似文献   

17.
Stephen Donovan  John Jagt 《Ichnos》2013,20(1-2):67-74
Three ichnospecies of Oichnus Bromley occur in tests of the large holasteroid echinoid Hemipneustes striatoradiatus (Leske) in the type area of the Maastrichtian (Upper Cretaceous) in The Netherlands and Belgium; Oichnus simplex Bromley (penetrative), Oichnus paraboloides Bromley (nonpenetrative and showing two distinct morphologies), and Oichnus excavatus isp. nov. (nonpenetrative). The two distinct morphologies of O. paraboloides (both shallow, one with a central boss) are gregarious, but do not occur together on the same specimens, suggesting they were generated by different taxa. Oichnus paraboloides with a central boss occurs on H. striatoradiatus from the upper Nekum Member, Maastricht Formation (Maastrichtian, Upper Cretaceous). Tests of the host echinoid are smaller in the overlying Meerssen Member, Maastricht Formation, where they are infested by O. excavatus, the largest borings considered herein, which have concave walls and a large central boss. Blisters inside tests from the Meerssen Member show that this infestation occurred when the echinoid was alive. It is postulated that producers of these borings in H. striatoradiatus may have been genetically related and increased in size during the Maastrichtian even as the host echinoids showed a size decrease. This size increase in H. striatoradiatus was genetic and cannot be related to increase in size of borings.  相似文献   

18.
In this paper we present and discuss palynological results based on a composite profile from Birkat Ram crater lake (Northern Golan, Near East) in order to reconstruct the environmental history, including human impact, of the last 6500 years. Furthermore we apply a newly-developed botanical climatological transfer function to reconstruct climate variations in the northern Golan Heights based on this pollen data-set. The Birkat Ram record is strongly influenced by anthropogenic indicators in the pollen diagram with high quantities during the Chalcolithic period/Early Bronze Age, during the Hellenistic-Roman-Byzantine periods, during the Crusader period and finally during modern times. The palaeoclimate reconstruction method used is based on a Bayesian approach and is robust in avoiding the influence of these strong anthropogenic signals on the reconstruction results. The area has always had Mediterranean climate conditions and no distinctive climate changes can be identified during the past 6500 years. Because of the orography of the Mt. Hermon region the particular geographical position of the northern Golan Heights is obviously capable of buffering large-scale fluctuations in precipitation, which have otherwise been documented for several regions in the Near East. Electronic Supplementary Material Supplementary material is available for this article at An erratum to this article can be found at  相似文献   

19.
《Palaeoworld》2020,29(2):439-452
Reconstructing the terrestrial palaeoenvironment during the end-Permian is made challenging by widespread erosion and ecosystem destruction. High-resolution sampling for palynofacies and palynology in sections that preserve the boundary interval allows for detailed examination of the drastic environmental changes that characterize the Permian–Triassic mass extinction. In the Bowen and Galilee basins in eastern Australia, this environmental perturbation is recorded within a Marker Mudstone that occurs above the uppermost Permian coal seams. The Marker Mudstone is used as a stratigraphic reference level at many localities, but has previously only been studied at a single locality in the Bowen Basin. In the present study, borehole Tambo 1-1A drilled in the Galilee Basin was selected to clarify whether this black, organic-rich mudstone marks a marine transgression, and to examine potential indicators of the end-Permian mass extinction. A total of 22 samples were taken from the mudstone unit, and from the over- and underlying strata and processed for palynology, palynofacies, and carbon isotope analysis.Biostratigraphic data indicate that the Marker Mudstone itself covers the uppermost part of unit APP5, with the first index taxa of unit APP6 floras occurring in samples less than 80 cm above this interval. This can be correlated with several other localities in the Bowen and Sydney basins where this shift occurs just above the uppermost Permian coal seam. Palynofacies data agree with previous interpretations of a southwards prograding delta that subsides as base level rises to form an extensive waterbody in which the Marker Mudstone was deposited. A change from translucent phytoclast-dominated to opaque phytoclast-dominated palynofacies within the Marker Mudstone suggests a shift to more oxic conditions in the water column, while base level begins to fluctuate, or increased terrestrial input from fluvial systems as the hinterland rises. Algal bodies resembling Botryococcus are found in the strata above the Marker Mudstone, but differ in morphology from the algal bodies found in the deltaic facies below. The presence of acanthomorph acritarchs in the Marker Mudstone and in the overlying Rewan Formation may indicate marine influence. Forms resembling fungal spores are present, but they do not show a “spike” as seen in other P–T boundary localities.The relative position of unit APP6 to the P–T boundary itself remains unclear. APP6 assemblages are dominated by simple acavate trilete and cavate trilete spores, which suggests stressed environment dominated by ferns and lycopods. The presence of degraded phytoclasts towards the top of the Marker Mudstone may also be used to suggest a mass-extinction interval. They may also be indicative of shifting local palaeoenvironmental changes, an interpretation that is supported by the low magnitude negative excursion of the δ13C isotope values within the Marker Mudstone. More datasets from the Bowen and Galilee basins will be essential to decoupling these signals.  相似文献   

20.
The construction of a new motorway necessitated the excavation of an Early Neolithic site in the Dutch Flevopolder near the Hoge Vaart canal. In 1994-1996, an area of ca. 1700 m2 was excavated in 0.5x0.5-m squares. The excavation revealed 150 surface hearths and more than a hundred deep hearth pits. The finds, mainly flint and pottery, as well as14C dates from charcoal demonstrated that the area had been used mainly during the Early Neolithic (ca. 4900–4500 cal. B.C.). The investigation of the Early Neolithic remains included detailed botanical analyses of 182 samples and hand-sorting by the excavation team, which included archaeobotanists, of tens of thousands of samples sieved over 2-mm-mesh sieves. No remains of cultivated plants were recognised among the 87 taxa (40 identified to species level) that were preserved, mainly in carbonised form. These results are compared with other Early Neolithic sites studied in the Netherlands, such as Swifterbant S3 and Schokland P14. The possible significance of site function and sample location as important factors influencing presence/absence of cultivated plant remains at a particular site is discussed.  相似文献   

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