References of "Palaeogeography, Palaeoclimatology, Palaeoecology"
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See detailMiddle Miocene climate and vegetation models and their validation with proxy data
Henrot, Alexandra-Jane ULg; Utescher, T.; Erdei, B. et al

in Palaeogeography, Palaeoclimatology, Palaeoecology (2016)

The Miocene is a relatively recent epoch of the Earth's history with warmer climate than today, particularly during the middle Miocene Climatic Optimum (MMCO, approximately 17-15Ma). Although the cause of ... [more ▼]

The Miocene is a relatively recent epoch of the Earth's history with warmer climate than today, particularly during the middle Miocene Climatic Optimum (MMCO, approximately 17-15Ma). Although the cause of the warming is probably not only attributable to CO2, but also to changes in orography and configuration of ocean gateways, this time interval represents an ideal case study to test the ability of climate models to simulate warm climates comparable to those that the Earth may experience in the near future. However, even with higher than present-day CO2 concentrations, the MMCO warming inferred from terrestrial proxy data has been difficult to reproduce in climate models.Since fossil flora do not provide direct information on climate, but on flora and vegetation, climate model results are generally compared to climate reconstructions obtained from the fossil flora. In this study, we apply an alternative method by simulating palaeovegetation from the outputs of the climate model, using a dynamic vegetation model. Model vegetation reconstruction can then be compared to the vegetation cover indicated by the fossil flora record at the various localities, provided that a common classification of plant functional types (PFTs) is used for the data and the model. Here, we reconstruct the vegetation of the middle Miocene with the global dynamic vegetation model CARAIB, using the climatologies derived from five atmospheric general circulation models. The reliability of the simulations is examined on a presence/absence basis of PFTs by comparison of vegetation reconstructions to palaeoflora data recorded in the Northern Hemisphere and the Tropics.This comparison provides an overall agreement around 60% between model and data, when all sites and tree types are considered. Three model simulations out of five show to be better at predicting the absence than the presence. The presence of warm-temperate mixed forests in the middle latitudes, dominated by broadleaved deciduous warm temperate and subtropical trees is generally well reproduced in CARAIB simulations. However, poor agreement is obtained for the presence of tropical PFTs out of the Tropics and for warm PFTs at latitudes northward of 50°N, where climate models remain too cold to produce assemblages of trees consistent with the data. Nevertheless, the model-data comparison performed here highlights several mismatches that could result not only from missing feedbacks in the climate simulations, but also from the data. The results of the likelihood analysis on presence/absence of PFTs illustrate the uncertainties in the PFT classification of the Neogene floral records. The coexistence of some PFTs in the palaeovegetation data is impossible to reproduce in the vegetation model simulations because of the climatic definition of the modern PFTs. This result indicates either a bias in the identification of modern analogues for fossil plant taxa, or a possible evolution of environmental requirements of certain plants. © 2016 Elsevier B.V. [less ▲]

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See detailEarly seed plants from Western Gondwana: Paleobiogeographical and ecological implications based on Tournaisian (Lower Carboniferous) records from Argentina
Prestianni, C.; Rustan, J.J.; Balseiro, D. et al

in Palaeogeography, Palaeoclimatology, Palaeoecology (2015), 417

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See detailEnvironmental and Climatic Changes during the Pleistocene-Holocene in the Bor Plain, Central Anatolia, Turkey
Altin, T.; El Ouahabi, Meriam ULg; Fagel, Nathalie ULg

in Palaeogeography, Palaeoclimatology, Palaeoecology (2015)

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See detailDiversity patterns of the vascular plant group Zosterophyllopsida in relation to Devonian palaeogeography
Cascales - Miñana, Borja ULg; Meyer-Berthaud, Brigitte

in Palaeogeography, Palaeoclimatology, Palaeoecology (2015), 423

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See detailSedimentary records of past earthquakes in Boraboy Lake during the last ca 600 years (North Anatolian Fault, Turkey).
Avsar, Ulas; Hubert, Aurélia ULg; De Batist, Marc et al

in Palaeogeography, Palaeoclimatology, Palaeoecology (2015), (433), 1-9

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See detailPalaeogeographical and palaeoecological constraints on palaeozoic vertebrates (chondrichthyans and placoderms) in the Ardenne Massif - Shark radiations in the Famennian on both sides of the Paleotethys
Derycke, Claire; Olive, Sébastien ULg; Groessens, Eric et al

in Palaeogeography, Palaeoclimatology, Palaeoecology (2014), 414

Three chondrichthyan radiations are registered in the Famennian of the ArdenneMassif (Belgium). These radiations are already observed in Morocco and in the Carnic Alps, their acme being related with the ... [more ▼]

Three chondrichthyan radiations are registered in the Famennian of the ArdenneMassif (Belgium). These radiations are already observed in Morocco and in the Carnic Alps, their acme being related with the early expansa transgression. Comparisons of univariate statistical descriptors like Margalef richness and Shannon–Wiener diversity index show variations between both margins of the Paleotethys, variations interpreted in terms of trophic relationships. The Ardenne area, a northern shallow carbonate platform is characterized during the Famennian by endemic shark taxa with durophagous dentition. The southern open deep-sea area, the Variscan Sea, contains large placoderms probably disclosing a negative feedback on “cladodont” chondrichthyans. This supports the hypothesis that the Armorica platelet behaved like a barrier between the central southern Laurussia and northern Gondwana. [less ▲]

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See detailIntegrated bio-chemostratigraphical correlations and climatic evolution across the Danian-Selandian boundary at low latitudes
Storme, Jean-Yves ULg; Steurbaut, Etienne; Devleeschouwer, Xavier et al

in Palaeogeography, Palaeoclimatology, Palaeoecology (2014), 414

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See detailThe Coexistence Approach--theoretical background and practical considerations of using plant fossils for climate quantification
Utescher, T.; Bruch, A. A.; Erdei, B. et al

in Palaeogeography, Palaeoclimatology, Palaeoecology (2014), 410

The Coexistence Approach was established by Mosbrugger and Utescher (1997) as a plant-based method to re- construct palaeoclimate by considering recent climatic distribution ranges of the nearest living ... [more ▼]

The Coexistence Approach was established by Mosbrugger and Utescher (1997) as a plant-based method to re- construct palaeoclimate by considering recent climatic distribution ranges of the nearest living relatives of each fossil taxon. During its existence for over more than 15 years, its basics have been tested and reviewed in comparison with other terrestrial and marine climate reconstruction techniques and climate modelling data. However, some controversies remain about its underlying data or its applicability in general. In view of these controversies this paper discusses the power and limitations of the Coexistence Approach by summarising past results and new developments. We give insights into the details and problems of each step of the application from the assignment of the fossil plant to the most suitable nearest living relative, the crucial consideration of the usefulness of specific taxa towards their climatic values and the correct interpretation of the software-based suggested palaeoclimatic intervals. Furthermore, we reflect on the fundamental data inte- grated in the Coexistence Approach by explaining different concepts and usages of plant distribution information and the advantages and disadvantages of modern climatic maps. Additionally, we elaborate on the importance of continually updating the information incorporated in the database due to new findings in e.g., (palaeo-)botany, meteorology and computer technology. Finally, for a transparent and appropriate use, we give certain guidelines for future applications and emphasize to users how to carefully consider and discuss their results. We show the Coexistence Approach to be an adaptive method capable of yielding palaeoclimatic and palaeoenvironmental information through time and space. [less ▲]

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See detailPaleohydrological and paleoenvironmental changes recorded in terrestrial sediments of the Paleocene-Eocene boundary (Normandy, France)
Garel, S.; Schnyder, J.; Jacob, J. et al

in Palaeogeography, Palaeoclimatology, Palaeoecology (2013), 376

The Paleocene-Eocene boundary (55.8. Ma) is associated with the Paleocene-Eocene Thermal Maximum (PETM), which is characterized by a negative Carbon Isotope Excursion (CIE), reflecting a major ... [more ▼]

The Paleocene-Eocene boundary (55.8. Ma) is associated with the Paleocene-Eocene Thermal Maximum (PETM), which is characterized by a negative Carbon Isotope Excursion (CIE), reflecting a major perturbation of the carbon cycle, and by an extreme and rapid global warming. The Cap d'Ailly area (Upper Normandy, France), in which previous studies have revealed the Paleocene-Eocene transition, is a reference locality for organic-rich terrestrial and lagoonal deposits of the "Sparnacian" stage, widespread in Northwestern Europe. In this study, we focus on the organic matter content of the Vasterival section. Organic data (Rock-Eval, palynofacies, biomarker analyses and compound specific isotope analyses) were acquired in order to constrain the paleoenvironmental and paleohydrological changes that occurred at the Paleocene-Eocene boundary. Stable carbon isotope compositions of higher plant leaf wax n-alkanes reveal a CIE of - 4.5‰, extending throughout the second half of the studied section. Palynofacies observations reveal: (i) an abrupt shift from a closed, quiescent marsh pond to an open eutrophic swamp subjected to algal blooms, concomitant with the onset of the CIE; and (ii) the evolution from a swamp to a tidal flat due to the marine transgression that occurred during the PETM. Higher plant biomarkers and their hydrogen isotopic composition compared to nitrogen analyses suggest: (i) dry episodes just before the PETM that may help to understand the triggering of this hyperthermal event; and (ii) a moister climate associated with a stronger seasonality during the early PETM.© 2013 ElsevierB.V. [less ▲]

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See detailBiochemostratigraphy of the upper Frasnian in the Namur–Dinant Basin, Belgium: Implications for a global Frasnian–Famennian pre-event
Azmy, Karem; Poty, Edouard; Mottequin, Bernard ULg

in Palaeogeography, Palaeoclimatology, Palaeoecology (2012), 313-314

The Upper Frasnian sequence of the Namur–Dinant Basin in southern Belgium consists of mixed siliclastic–carbonate succession of a ramp setting, where the sequence spans the rhenana–linguiformis conodont ... [more ▼]

The Upper Frasnian sequence of the Namur–Dinant Basin in southern Belgium consists of mixed siliclastic–carbonate succession of a ramp setting, where the sequence spans the rhenana–linguiformis conodont zones. Earlier studies investigated the chemostratigraphic variations during the Frasnian-Famennian event, but little has been yet known about the nature of the counterpart variations that immediately preceded that time interval. Despite the scarcity of well-preserved brachiopods, sixty–one calcitic shells were collected mainly from beds of the Neuville and Les Valisettes formations (Lower and Upper rhenana zones), to investigate biochemostratigraphic profiles of oxygen-, carbon-isotope and rare earth element (REE) variations of the time interval immediately before the Frasnian-Famennian boundary. The δ18O and δ13 C values of the well-preserved shells range from − 9.5 to − 5.6 ‰ VPDB (− 7.7 ± 1.1, n = 33) and from − 1.8 to 3.8 ‰ VPDB (1.1 ± 1.7, n = 33), respectively, which are within the documented global values. The C- and O-isotope profiles exhibit parallel shifts, particularly at the top of the Neuville Formation (top of the Lower rhenana Zone), which are associated with a sea-level rise and shrinkage in the brachiopod community. Also, the Th/U (0.9 ± 0.6, n = 16) and Ce/Ce* (2.2 ± 0.5, n = 16) ratios suggest deposition under reducing conditions consistent with sea transgression. [less ▲]

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See detailDid a Katian Large Igneous Province trigger the Late Ordovician glaciation ? A hypothesis tested with a carbon cycle model
Lefebvre, Vincent; Servais, Thomas; François, Louis ULg et al

in Palaeogeography, Palaeoclimatology, Palaeoecology (2010), 296

The Ordovician is known as a period with high temperatures and high sea levels and a cooling event at the end of the period, leading to the Hirnantian glaciation and the !rst of the ‘big !ve’ mass ... [more ▼]

The Ordovician is known as a period with high temperatures and high sea levels and a cooling event at the end of the period, leading to the Hirnantian glaciation and the !rst of the ‘big !ve’ mass extinctions of marine life. The cause of this cooling event remains unclear. Several authors correlate it with a drop in atmospheric pCO2 to a threshold permitting the ice accumulation on the Gondwana supercontinent. However, what are the reasons of the atmospheric pCO2 decrease? Here, we follow the hypothesis initiated by Barnes (2004) that an Ordovician superplume event occurred during the Middle to Late Ordovician. Such an event would not only have a large impact on the Ordovician biodiversi!cation (Barnes, 2004) but it would also be responsible for the climatic upheaval during the Late Ordovician by the emplacement of a low latitudinal continental basaltic province that had an impact on the atmospheric pCO2. There is no direct evidence of a superplume event or of basaltic traps and the present study is therefore a hypothetical modelling approach where we demonstrate with a numerical box model, including carbon, alkalinity and phosphorus cycles coupled with a 1D climate model (energy balance model-EBM) (François and Walker,1992), that such a scenario allows to explain both the mid-Ashgill (Katian) global warming event, known as the Boda Event (Fortey and Cocks, 2005), and the subsequent Late Ordovician (Hirnantian) glaciation. Because silicate weathering is enhanced upon warm and wet climate, we try to constrain the size and the latitudinal emplacement of the basaltic province leading to a suf!cient consumption of atmospheric pCO2 to the threshold proposed by Herrmann et al. (2004 a, b) to initiate a glaciation on Gondwana. [less ▲]

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See detailBulk organic geochemistry of sediments from Puyehue Lake and its watershed (Chile, 40°S): Implications for paleoenvironmental reconstructions
Bertrand, Sébastien; Sterken, Mieke; Vargas-Ramirez, Lourdes et al

in Palaeogeography, Palaeoclimatology, Palaeoecology (2010), 294

Since the last deglaciation, the mid-latitudes of the southern Hemisphere have undergone considerable environmental changes. In order to better understand the response of continental ecosystems to ... [more ▼]

Since the last deglaciation, the mid-latitudes of the southern Hemisphere have undergone considerable environmental changes. In order to better understand the response of continental ecosystems to paleoclimate changes in southern South America, we investigated the sedimentary record of Puyehue Lake, located in the western piedmont of the Andes in South-Central Chile (40°S). We analyzed the elemental (C, N) and stable isotopic ([delta]13C, [delta]15N) composition of the sedimentary organic matter preserved in the lake and its watershed to estimate the relative changes in the sources of sedimentary organic carbon through space and time. The geochemical signature of the aquatic and terrestrial end-members was determined on samples of lake particulate organic matter (N/C: 0.130) and Holocene paleosols (N/C: 0.069), respectively. A simple mixing equation based on the N/C ratio of these end-members was then used to estimate the fraction of terrestrial carbon ([latin small letter f with hook]T) preserved in the lake sediments. Our approach was validated using surface sediment samples, which show a strong relation between [latin small letter f with hook]T and distance to the main rivers and to the shore. We further applied this equation to an 11.22 m long sediment core to reconstruct paleoenvironmental changes in Puyehue Lake and its watershed during the last 17.9 kyr. Our data provide evidence for a first warming pulse at 17.3 cal kyr BP, which triggered a rapid increase in lake diatom productivity, lagging the start of a similar increase in sea surface temperature (SST) off Chile by 1500 years. This delay is best explained by the presence of a large glacier in the lake watershed, which delayed the response time of the terrestrial proxies and limited the concomitant expansion of the vegetation in the lake watershed (low [latin small letter f with hook]T). A second warming pulse at 12.8 cal kyr BP is inferred from an increase in lake productivity and a major expansion of the vegetation in the lake watershed, demonstrating that the Puyehue glacier had considerably retreated from the watershed. This second warming pulse is synchronous with a 2 °C increase in SST off the coast of Chile, and its timing corresponds to the beginning of the Younger Dryas Chronozone. These results contribute to the mounting evidence that the climate in the mid-latitudes of the southern Hemisphere was warming during the Younger Dryas Chronozone, in agreement with the bipolar see-saw hypothesis. [less ▲]

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See detailFamennian charcoal of Belgium.
Prestianni, Cyrille ULg; Decombeix, Anne-laure; Thorez, Jacques ULg et al

in Palaeogeography, Palaeoclimatology, Palaeoecology (2010)

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See detailCarbon-isotope analysis of fossil wood and dispersed organic matter from the terrestrial Wealden facies of Hautrage (Mons Basin, Belgium).
Yans, Johan; Gerards, Thomas ULg; Gerrienne, Philippe ULg et al

in Palaeogeography, Palaeoclimatology, Palaeoecology (2010), 291

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See detailWeathering in the Lake Baikal watershed during the Kazantsevo (Eemian) interglacial: Evidence from the lacustrine clay record
Fagel, Nathalie ULg; Mackay, Anson W

in Palaeogeography, Palaeoclimatology, Palaeoecology (2008), 259(2-3), 244-257

The clay-mineralogical record of a piston core recovered on an elevated plateau in the northern basin of Lake Baikal has been investigated for the Kazantsevo interglacial period (i.e., Eemian s.s ... [more ▼]

The clay-mineralogical record of a piston core recovered on an elevated plateau in the northern basin of Lake Baikal has been investigated for the Kazantsevo interglacial period (i.e., Eemian s.s. equivalent in northern Europe). The age model (as inferred from palaeomagnetic intensity) suggests that this stage spans ca. 128 to 117 kyr BP. Relative clay mineral abundances and clay-mineral ratios are used to reconstruct the weathering conditions within the Baikal watershed at a sub-millennial resolution, and suggest that the clay record is highly variable. A bimodal clay-data distribution is in agreement with different clay sources and/or formation between the studied glacial and interglacial periods. High amounts of smectites in the Taz glacial samples (128.7-136.4 kyr BP) may be explained by an additional source of neoformed smectites during the glacial stage. In addition to the classically used smectite/illite ratio, the mineralogical results are integrated by the calculation of a hydrolysis index that takes into account the abundance of all clay species and their sensitivity to chemical weathering. A principal components analysis (PCA) of the Baikal clay minerals allows the comparison of the clay parameters with regard to weathering conditions. Clay data are further compared (i) with diatom and pollen profiles, (ii) with pollen-based quantitative reconstructions for the same core material, and (iii) with other climate reconstructions for the Lake Baikal region and Siberia. Several features of our record are highlighted here. During the early period of the Kazantsevo interglacial (128.4-125.2 kyr BP), weathering processes remain controlled by physical reworking for more than 2 kyr after the initial transition from cold to warm conditions. Inception of chemical weathering starts only after ca. 125 kyr BP, a period coincident with the warmest conditions according to both the pollen record and by the strongest chernozem development in Siberian soils. Within the interglacial interval, the hydrolysis index displays a two-step increase, punctuated by a minimum value ca. 122 kyr BP. The increasing but irregular trend persists after the transition from the Kazantsevo interglacial to the Zyryanka glacial (similar to 117 kyr BP). Peak chemical weathering, as inferred by clay changes, lags the interglacial/ glacial transition by at least 2 kyr. This suggests that pedogenesis remains active after the interval of surface stabilization. Lake Baikal clay minerals trace the nature of the main weathering conditions within the watershed. We note any increase in physical weathering is rapidly recorded in sedimentary clay assemblages but the mineral imprint to chemical weathering changes is more gradual, lagging reconstructed climate conditions over the lake by ca. 2 kyr. 0 2007 Elsevier B.V.. All rights reserved. [less ▲]

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See detailClay-mineral record in Lake Baikal sediments: The Holocene and Late Glacial transition
Fagel, Nathalie ULg; Boes, Xavier

in Palaeogeography, Palaeoclimatology, Palaeoecology (2008), 259(2-3), 230-243

We analyse the clay-mineralogical composition of two 1-m long cores from elevated plateaus in the southern and northern basins of Lake Baikal. Our aim is to test the limits of classically used clay ... [more ▼]

We analyse the clay-mineralogical composition of two 1-m long cores from elevated plateaus in the southern and northern basins of Lake Baikal. Our aim is to test the limits of classically used clay proxies for climate reconstructions. Mineralogical signature is determined by X-ray diffraction on oriented aggregates from Holocene and Late Glacial sediments. Mineralogical results are presented on a palaeomagnetic-derived time scale. Sampling at a centimeter resolution allows for a sub-millenial order reconstruction. The evolution of clay-derived climate proxies (smectite/illite peak intensity ratio, S/I) is compared between the two locations, with respect to other climate reconstructions for the Lake Baikal area and Siberia. During the Late Glacial punctual increases of S/I are related to changes of particle source rather than any climate change. At both sites the most intense chemical weathering conditions occured during the Subboreal, lagging the Eurasian middle Atlantic climate optimum. S/I follows a gradual but irregular increase through the Holocene, probably related to slow warming favourable to the development of the Siberian soils. The different sensitivity to hydrolysing conditions in northern and southern sites can be explained by a combination of local lithological and topographical parameters. (c) 2007 Elsevier B.V. All rights reserved. [less ▲]

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See detailCarbon isotope lateral variability in a Middle Frasnian carbonate platform (Belgium): significance of facies, diagenesis and sea-level history
Da Silva, Anne-Christine ULg; Boulvain, Frédéric ULg

in Palaeogeography, Palaeoclimatology, Palaeoecology (2008), 269

Carbon isotopic variations of Frasnian shallow-water carbonates from Belgium are related to facies and major sea-level trends. The influence of the diagenetic overprint was assessed in order to determine ... [more ▼]

Carbon isotopic variations of Frasnian shallow-water carbonates from Belgium are related to facies and major sea-level trends. The influence of the diagenetic overprint was assessed in order to determine the primary signal of the Frasnian carbonates. Shallow-water microfacies are characterized by biostromes with stromatoporoids and lagoonal deposits dominated by carbonate mud and calcareous algae with subaerial exposure surfaces. The diagenetic history was controlled by three main events: early meteoric diagenesis (short-term subaerial exposure during deposition), late meteoric diagenesis (major Famennian regression) and burial diagenesis. The oxygen isotopic values are almost constant with respect to facies, original material (carbonate mud and cement) and sedimentological units (no differences before or after the main regression). This homogeneity is related to resetting during late meteoric diagenesis. The carbon isotopic values are related to facies (with the more negative values for the shallowest facies) and to major sea-level variations (most negative values after the main regression). This pattern is interpreted as being related to primary signals. This trend was enhanced by early meteoric diagenesis and the influence of more negative values from paleosols. The carbon isotope patterns reflect the influence of sea-level and water circulation on shallow water deposits and this influence implies that shallow-water carbonates are not necessarily good material for assessing the primary isotopic values of the ocean because of the influence of long residence time (“aging”) of the platform-top water and because of early diagenesis. [less ▲]

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See detailPalaeophytogeographical and palaeoecological implications of a miospore assemblage of earliest Devonian (Lochkovian) age from Saudi Arabia
Steemans, Philippe ULg; Wellman, C. H.; Filatoff, J.

in Palaeogeography, Palaeoclimatology, Palaeoecology (2007), 250(1-4), 237-254

Palynological samples from two boreholes drilled in the eastern part of Saudi Arabia contain a rich assemblage of cryptospores and trilete spores. They are dated as most probably Lochkovian in age ... [more ▼]

Palynological samples from two boreholes drilled in the eastern part of Saudi Arabia contain a rich assemblage of cryptospores and trilete spores. They are dated as most probably Lochkovian in age. Intriguingly, the cryptospores are very similar to those from a coeval continental palynomorph assemblage from the Old Red Sandstone Continent, whereas the trilete spores show a strong affinity with miospore assemblages from Western Gondwana. It is suggested that cryptospore-producing plants inhabited confined, damp biotopes and had a wide range of climatic tolerance. On the otherhand, trilete spore-producing plants inhabited a wider variety of biotopes but were more sensitive to climatic variations. The high degree of similarity between Old Red Sandstone and Saudi Arabian cryptospore assemblages favours palaeogeographic reconstructions where there is close proximity between Western Gondwana and Euramerica and/or a land connection between these palaeoplates. Climatic differences between the Old Red Sandstone Continent and the northern part of Western Gondwana can be invoked to explain the variations in the trilete spore assemblages. (c) 2007 Elsevier B.V. All rights reserved. [less ▲]

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See detailTree diversity in the Miocene forests of western Eurasia
Utescher, T.; Erdei, B.; François, Louis ULg et al

in Palaeogeography, Palaeoclimatology, Palaeoecology (2007), 253(1-2), 226-250

In the present study, published Miocene mega- and microfloral records compiled from a total of 92 localities in Western Eurasia are analysed with respect to diversity of different plant functional types ... [more ▼]

In the present study, published Miocene mega- and microfloral records compiled from a total of 92 localities in Western Eurasia are analysed with respect to diversity of different plant functional types (PFTs). To study spatial diversity patterns and their evolution three time-intervals are selected corresponding to the Langhian (16.3-13.6 Ma), the Serravallian (13.6-11.6), and the earlier part of the Tortonian (11.6-8.5 Ma). First all arboreal species occurring in the floras are classified using a total of 13 different PFTs (functional types of trees and climatically defined subtypes). In a next step, diversity spectra with respect to these PFTs are generated for each site. Cluster analysis is then performed in order to obtain groups of floras with similar spectra that are interpreted in terms of vegetation type. Their spatial distribution in each time-interval is shown in maps. According to these results, zonally arranged patterns are obtained. Broadleaved Deciduous Forests are most important in the higher latitudes while Mixed Mesophytic Forests dominate the mid-latitudes in Western Eurasia. Broadleaved Evergreen Forests are of minor importance in the area of interest. The observed diversity patterns and their changes in time are correlated with spatial climate patterns and the continental palaeoclimate evolution. During the late Miocene cooling, Broadleaved Evergreen Forests completely disappear from the mid-latitudes of Western Eurasia, and Mixed Mesophytic Forests of the mid-latitudes are mostly replaced by broadleaved deciduous vegetation types. In the context of this cooling, a drier season became established in Western Europe during the Tortonian, as is evident from reconstructed arboreal diversity data and precipitation data. In Central Europe, vegetation types indicating permanently humid conditions persisted throughout all the three time-intervals analysed. (C) 2007 Elsevier B.V. All rights reserved. [less ▲]

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See detailUpper Devonian carbonate platform correlations and sea level variations recorded in magnetic susceptibility
Da Silva, Anne-Christine ULg; Boulvain, Frédéric ULg

in Palaeogeography, Palaeoclimatology, Palaeoecology (2006), 240(3-4), 373-388

This paper: concerns the analysis of four outcrops in the Frasnian (Upper Devonian) of Belgium. We compare the results of a precise sedimentological analysis with magnetic susceptibility (MS) data. This ... [more ▼]

This paper: concerns the analysis of four outcrops in the Frasnian (Upper Devonian) of Belgium. We compare the results of a precise sedimentological analysis with magnetic susceptibility (MS) data. This comparison allows us to improve stratigraphic correlations and to test the relationship between magnetic susceptibility and sea level changes. Considering the sedimentological study, different microfacies have been identified, from the external belt dominated by relatively argillaceous open marine facies with crinoids, to the biostromal and the lagoonal belt dominated by algae-rich muddy facies. Fourth- and third-order sequences have also been identified and are probably related to sea level variations. Magnetic susceptibility data provides us very good fourth-order correlations and the link between magnetic susceptibility and different sedimentological parameters is obvious. More precisely, MS appears to be related to fourth- and third-order sequences and to microfacies. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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